Journal articles: 'Pai-Conjugated Molecular Materials Electronic Structure'

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Men, Xiaoju, and Zhen Yuan. "Multifunctional conjugated polymer nanoparticles for photoacoustic-based multimodal imaging and cancer photothermal therapy." Journal of Innovative Optical Health Sciences 12, no. 03 (May 2019): 1930001. http://dx.doi.org/10.1142/s1793545819300015.

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Photoacoustic imaging (PAI) is a hybrid imaging method based on photoacoustic (PA) effects, which is able to capture the structure, function, and molecular information of biological tissues with high resolution. To date, therapeutic techniques under the guidance of PAI have provided new strategies for accurate diagnosis and precise treatment of tumors. In particular, conjugated polymer nanoparticles have been extensively inspected for PA-based cancer theranostics largely due to their superior optical properties such as tunable spectrum and large absorption coefficient and their good biocompatibility, and abundant functional groups. This mini-review mainly focuses on the recent advances toward the development of novel conjugated polymer nanoparticles for PA-based multimodal imaging and cancer photothermal therapy.

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Caciuc, V., M. C. Lennartz, N. Atodiresei, S. Karthäuser, and S. Blügel. "Fine tuning of the electronic structure of π-conjugated molecules for molecular electronics." Nanotechnology 22, no. 14 (February 24, 2011): 145701. http://dx.doi.org/10.1088/0957-4484/22/14/145701.

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Dong, Xiaodi, Mingsheng Zheng, Baoquan Wan, Xuejie Liu, Haiping Xu, and Junwei Zha. "Low—Permittivity Copolymerized Polyimides with Fluorene Rigid Conjugated Structure." Materials 14, no. 21 (October 21, 2021): 6266. http://dx.doi.org/10.3390/ma14216266.

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As the miniaturization of electronic appliances and microprocessors progresses, low-permittivity interlayer materials are becoming increasingly important for their suppression of electronic crosstalk, signal propagation delay and loss, and so forth. Herein, a kind of copolyimide (CPI) film with a “fluorene” rigid conjugated structure was prepared successfully. By introducing 9,9-Bis(3-fluoro-4-aminophenyl) fluorene as the rigid conjugated structure monomer, a series of CPI films with different molecular weights were fabricated by in situ polymerization, which not only achieved the reduction of permittivity but also maintained excellent thermodynamic stability. Moreover, the hydrophobicity of the CPI film was also improved with the increasing conjugated structure fraction. The lowest permittivity reached 2.53 at 106 Hz, while the thermal decomposition temperature (Td5%) was up to 530 °C, and the tensile strength was ≥ 96 MPa. Thus, the CPI films are potential dielectric materials for microelectronic and insulation applications.

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Lin, Chia-Yang, and Tsuyoshi Michinobu. "Conjugated photothermal materials and structure design for solar steam generation." Beilstein Journal of Nanotechnology 14 (April 4, 2023): 454–66. http://dx.doi.org/10.3762/bjnano.14.36.

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With the development of solar steam generation (SSG) for clean water production, conjugated photothermal materials (PTMs) have attracted significant interest because of their advantages over metallic and inorganic PTMs in terms of high light absorption, designable molecular structures, flexible morphology, and solution processability. We review here the recent progress in solar steam generation devices based on conjugated organic materials. Conjugated organic materials are processed into fibers, membranes, and porous structures. Therefore, nanostructure design based on the concept of nanoarchitectonics is crucial to achieve high SSG efficiency. We discuss the considerations for designing SSG absorbers and describe commonly used conjugated organic materials and structural designs.

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Kim, Jinsang. "Assemblies of conjugated polymers: Intermolecular and intramolecular effects on the photophysical properties of conjugated polymers." Pure and Applied Chemistry 74, no. 11 (January 1, 2002): 2031–44. http://dx.doi.org/10.1351/pac200274112031.

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Conjugated polymers are emerging materials for electronic applications due to the tunability of their properties through variation of their chemical structure. Their applications, which currently include light-emitting diodes (LEDs), field effect transistors (FETs), plastic lasers, batteries, and sensors, are expanding to many new areas. The two critical parameters that determine the function of conjugated polymer-based devices are chemical structure and nanostructure of a conjugated polymer in the solid state. While the physical properties of isolated polymers are primarily controlled by their chemical structure, these properties are drastically altered in the solid state due to electronic coupling between polymer chains as determined by their interpolymer packing and conformation. However, the development of effective and precise methods for controlling the nanostructure of polymers in the solid state has been limited because polymers often fail to assemble into organized structures due to their amorphous character and large molecular weight.In this review, recent developments of organizing methods of conjugated polymers and the conformation and interpolymer interaction effects on the photophysical properties of conjugated polymers are summarized.

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Salaneck, W. R., and J. L. Brédas. "Conjugated Polymer Surfaces and Interfaces for Light-Emitting Devices." MRS Bulletin 22, no. 6 (June 1997): 46–51. http://dx.doi.org/10.1557/s0883769400033625.

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Since the discovery of high electrical conductivity in doped polyacetylene in 1977, π-conjugated polymers have emerged as viable semiconducting electronic materials for numerous applications. In the context of polymer electronic devices, one must understand the nature of the polymer surface's electronic structure and the interface with metals. For conjugated polymers, photoelectron spectroscopy—especially in connection with quantum-chemical modeling—provides a maximum amount of both chemical and electronic structural information in one (type of) measurement. Some details of the early stages of interface formation with metals on the surfaces of conjugated polymers and model molecular solids in connection with polymer-based light-emitting devices (LEDs) are outlined. Then a chosen set of issues is summarized in a band structure diagram for a polymer LED, based upon a “clean calcium electrode” on the clean surface of a thin film of poly(p-phenylene vinylene) (PPV). This diagram helps to point out the complexity of the systems involved in polymer LEDs. No such thing as “an ideal metal-on-polymer contact” exists. There is always some chemistry occurring at the interface.

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Miao, Zongcheng, Yaqin Chu, Lei Wang, Wenqing Zhu, and Dong Wang. "Nonlinear Optical and Ion Sensor Properties of Novel Molecules Conjugated by Click Chemistry." Polymers 14, no. 8 (April 8, 2022): 1516. http://dx.doi.org/10.3390/polym14081516.

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The molecular structure, luminescence behavior, and electronic energy level of an organic optoelectronic materials are important parameters for its synthesis. The electro-optical properties can be changed by modifying the structure of the molecule to make the electronic energy level adjustable. In this article, a series of organic conjugated micro-molecules are successfully synthesized by linking small compound units. This metal-free [2 + 2] click chemistry process generates donor–acceptor chromophore substances with high yield, high solubility, and adjustable energy levels, which can be widely used for sensors and nonlinear optics in different fields. A-TCNE, A-TCNQ, and A-F4-TCNQ molecules are characterized comprehensively via UV-Vis-NIR spectra, 1H NMR spectra, infrared spectroscopy, and mass spectrometry. The unique nonlinear optical phenomena and powerful intra-molecular charge–transfer interactions of these new materials give them fascinating potential for application as optoelectronic materials.

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Kahn, Antoine, Norbert Koch, and Weiying Gao. "Electronic structure and electrical properties of interfaces between metals and ?-conjugated molecular films." Journal of Polymer Science Part B: Polymer Physics 41, no. 21 (October 8, 2003): 2529–48. http://dx.doi.org/10.1002/polb.10642.

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Matt, Clemens, Florian Lombeck, Michael Sommer, and Till Biskup. "Impact of Side Chains of Conjugated Polymers on Electronic Structure: A Case Study." Polymers 11, no. 5 (May 13, 2019): 870. http://dx.doi.org/10.3390/polym11050870.

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Processing from solution is a crucial aspect of organic semiconductors, as it is at the heart of the promise of easy and inexpensive manufacturing of devices. Introducing alkyl side chains is an approach often used to increase solubility and enhance miscibility in blends. The influence of these side chains on the electronic structure, although highly important for a detailed understanding of the structure-function relationship of these materials, is still barely understood. Here, we use time-resolved electron paramagnetic resonance spectroscopy with its molecular resolution to investigate the role of alkyl side chains on the polymer PCDTBT and a series of its building blocks with increasing length. Comparing our results to the non-hexylated compounds allows us to distinguish four different factors determining exciton delocalization. Detailed quantum-chemical calculations (DFT) allows us to further interpret our spectroscopic data and to relate our findings to the molecular geometry. Alkylation generally leads to more localized excitons, most prominent only for the polymer. Furthermore, singlet excitons are more delocalized than the corresponding triplet excitons, despite the larger dihedral angles within the backbone found for the singlet-state geometries. Our results show TREPR spectroscopy of triplet excitons to be well suited for investigating crucial aspects of the structure-function relationship of conjugated polymers used as organic semiconductors on a molecular basis.

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Gong, Pingping, Lili An, Junfeng Tong, Xinpeng Liu, Zezhou Liang, and Jianfeng Li. "Design of A-D-A-Type Organic Third-Order Nonlinear Optical Materials Based on Benzodithiophene: A DFT Study." Nanomaterials 12, no. 20 (October 21, 2022): 3700. http://dx.doi.org/10.3390/nano12203700.

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The acceptor-donor-acceptor (A-D-A) type conjugated organic molecule has been widely applied in the organic optoelectronics field. A total of Nine compounds (1–9) were designed under the A-D-A framework, with the electron donor benzodithiophene as the core and dicyanomethylene as the acceptor moiety, modifying the benzodithiophene with the phenyl, naphthyl, and difluorinated phenyl groups. The conjugation length can be changed by introducing a thiophene π-conjugated bridge. The geometric structures, electronic structure, excited state properties, aromaticity, and the static- and frequency-dependent second hyperpolarizabilities were investigated by employing high-precision density functional theory (DFT) calculations with an aug-cc-pVDZ basis set. As a result, the three compounds with the longest conjugation length exhibit a smaller energy gap (Egap), larger UV-vis absorption coefficient, and response range, which are the three strongest third-order nonlinear optical (NLO) response properties in this work. This work systematically explored the connection between molecular structure and NLO response, which provides a rational design strategy for high-performance organic NLO materials.

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Shimizu, Soji, and Nagao Kobayashi. "Structurally-modified subphthalocyanines: molecular design towards realization of expected properties from the electronic structure and structural features of subphthalocyanine." Chem. Commun. 50, no. 53 (2014): 6949–66. http://dx.doi.org/10.1039/c4cc01526f.

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This feature article summarizes recent contributions of the authors in the synthesis of structurally-modified subphthalocyanines, which covers (1) modification of the conjugated system, (2) core-modification, and (3) exterior-modification.

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Paulsen, Bryan D., Simone Fabiano, and Jonathan Rivnay. "Mixed Ionic-Electronic Transport in Polymers." Annual Review of Materials Research 51, no. 1 (July 26, 2021): 73–99. http://dx.doi.org/10.1146/annurev-matsci-080619-101319.

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Polymeric mixed ionic-electronic conductors (MIECs) combine aspects of conjugated polymers, polymer electrolytes, and polyelectrolytes to simultaneously transport and couple ionic and electronic charges, opening exciting new applications in energy storage and conversion, bioelectronics, and display technologies. The many applications of polymeric MIECs lead to a wide range of transport conditions. Ionic and electronic transport are directly coupled through electrochemical doping, while the mechanisms of ionic and electronic transport depend on distinctly different chemical functionality, (macro)molecular structure, and morphology. Despite this, ionic and electronic transport are surprisingly tunable, independent of one another. We review the various types of polymeric MIECs, the mechanisms of ionic and electronic charge transport across conditions, and the interrelations between the two, with special emphasis on the unique aspects of polymeric MIEC transport phenomena.

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McCreery, Richard L. "Effects of electronic coupling and electrostatic potential on charge transport in carbon-based molecular electronic junctions." Beilstein Journal of Nanotechnology 7 (January 11, 2016): 32–46. http://dx.doi.org/10.3762/bjnano.7.4.

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Molecular junctions consisting of 2–20 nm thick layers of organic oligomers oriented between a conducting carbon substrate and a carbon/gold top contact have proven to be reproducible and reliable, and will soon enter commercial production in audio processing circuits. The covalent, conjugated bond between one or both sp2-hybridized carbon contacts and an aromatic molecular layer is distinct from the more common metal/molecule or silicon/molecule structures in many reported molecular junctions. Theoretical observations based on density functional theory are presented here, which model carbon-based molecular junctions as single molecules and oligomers between fragments of graphene. Electronic coupling between the molecules and the contacts is demonstrated by the formation of hybrid orbitals in the model structure, which have significant electron density on both the graphene and the molecule. The energies of such hybrid orbitals correlate with tunneling barriers determined experimentally, and electronic coupling between the two graphene fragments in the model correlates with experimentally observed attenuation of transport with molecular layer thickness. Electronic coupling is affected significantly by the dihedral angle between the planes of the graphene and the molecular π-systems, but is absent only when the two planes are orthogonal. Coupling also results in partial charge transfer between the graphene contacts and the molecular layer, which results in a shift in electrostatic potential which affects the observed tunneling barrier. Although the degree of partial charge transfer is difficult to calculate accurately, it does provide a basis for the “vacuum level shift” observed in many experiments, including transport and ultraviolet photoelectron spectroscopy of molecular layers on conductors.

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Xiong, Miao, Jie-Yu Wang, and Jian Pei. "Controlling the Film Microstructure in Organic Thermoelectrics." Organic Materials 03, no. 01 (January 2021): 001–16. http://dx.doi.org/10.1055/s-0040-1722305.

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Doping is a vital method to increase the charge carrier concentration of conjugated polymers, thus improving the performance of organic electronic devices. However, the introduction of dopants may cause phase separation. The miscibility of dopants and polymers as well as the doping-induced microstructure change are always the barriers in the way to further enhance the thermoelectrical performance. Here, recent research studies about the influence of molecular doping on the microstructures of conjugated polymers are summarized, with an emphasis on the n-type doping. Highlighted topics include how to control the distribution and density of dopants within the conjugated polymers by modulating the polymer structure, dopant structure, and solution-processing method. The strong Coulombic interactions between dopants and polymers as well as the heterogeneous doping process of polymers can hinder the polymer film to achieve better miscibility of dopants/polymer and further loading of the charge carriers. Recent developments and breakthroughs provide guidance to control the film microstructures in the doping process and achieve high-performance thermoelectrical materials.

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Ren, Shiwei, and Abderrahim Yassar. "Recent Research Progress in Indophenine-Based-Functional Materials: Design, Synthesis, and Optoelectronic Applications." Materials 16, no. 6 (March 20, 2023): 2474. http://dx.doi.org/10.3390/ma16062474.

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This review highlights selected examples, published in the last three to four years, of recent advance in the design, synthesis, properties, and device performance of quinoidal π-conjugated materials. A particular emphasis is placed on emerging materials, such as indophenine dyes that have the potential to enable high-performance devices. We specifically discuss the recent advances and design guidelines of π-conjugated quinoidal molecules from a chemical standpoint. To the best of the authors’ knowledge, this review is the first compilation of literature on indophenine-based semiconducting materials covering their scope, limitations, and applications. In the first section, we briefly introduce some of the organic electronic devices that are the basic building blocks for certain applications involving organic semiconductors (OSCs). We introduce the definition of key performance parameters of three organic devices: organic field effect transistors (OFET), organic photovoltaics (OPV), and organic thermoelectric generators (TE). In section two, we review recent progress towards the synthesis of quinoidal semiconducting materials. Our focus will be on indophenine family that has never been reviewed. We discuss the relationship between structural properties and energy levels in this family of molecules. The last section reports the effect of structural modifications on the performance of devices: OFET, OPV and TE. In this review, we provide a general insight into the association between the molecular structure and electronic properties in quinoidal materials, encompassing both small molecules and polymers. We also believe that this review offers benefits to the organic electronics and photovoltaic communities, by shedding light on current trends in the synthesis and progression of promising novel building blocks. This can provide guidance for synthesizing new generations of quinoidal or diradical materials with tunable optoelectronic properties and more outstanding charge carrier mobility.

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Arooj, Qudsia, Gregory J. Wilson, and Feng Wang. "Methodologies in Spectral Tuning of DSSC Chromophores through Rational Design and Chemical-Structure Engineering." Materials 12, no. 24 (December 4, 2019): 4024. http://dx.doi.org/10.3390/ma12244024.

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The investigation of new photosensitizers for Grätzel-type organic dye-sensitized solar cells (DSSCs) remains a topic of interest for researchers of alternative solar cell materials. Over the past 20 years, considerable and increasing research efforts have been devoted to the design and synthesis of new materials, based on “donor, π-conjugated bridge, acceptor” (D–π–A) organic dye photosensitizers. In this paper, the computational chemistry methods are outlined and the design of organic sensitizers (compounds, dyes) is discussed. With reference to recent literature reports, rational molecular design is demonstrated as an effective process to study structure–property relationships. Examples from established organic dye sensitizer structures, such as TA-St-CA, Carbz-PAHTDDT (S9), and metalloporphyrin (PZn-EDOT), are used as reference structures for an examination of this concept applied to generate systematically modified structural derivatives and hence new photosensitizers (i.e., dyes). Using computer-aided rational design (CARD), the in silico design of new chromophores targeted an improvement in spectral properties via the tuning of electronic structures by substitution of molecular fragments, as evaluated by the calculation of absorption profiles. This mini review provides important rational design strategies for engineering new organic light-absorbing compounds towards improved spectral absorption and related optoelectronic properties of chromophores for photovoltaic applications, including the dye-sensitized solar cell (DSSC).

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Jones, R., S. J. Rettig, J. R. Scheffer, J. Trotter, and J. Yang. "Structures and photochemistry of 1,5-disubstituted dibenzobarrelenes." Acta Crystallographica Section B Structural Science 52, no. 1 (February 1, 1996): 151–58. http://dx.doi.org/10.1107/s0108768195005854.

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The effect of 1,5-disubstitution on the photochemistry of 9,10-ethenoanthracene-11,12-diesters has been studied and correlated with the crystal structures determined for several derivatives; photoproduct structures have been established from a crystal structure analysis of one of the products and from NMR correlations. The crystals studied are: (1)-Cl, dimethyl 1,5-dichloro-9,10-dihydro-9,10-ethenoanthracene-11,12-dicarboxylate, C20H14Cl2O4, P21/n; (1)-CN, 1,5-dicyano derivative, C22H14N2O4, P21/n; (1)-CN.0.5p-xylene, C22H14N2O4.0.5C8H10, P21/c; (1)-CN.xxylene, C22H14N2O4.xC8H10, P21/n; (1)-OMe, 1,5-dimethoxy derivative, C22H20O6, P{\bar 1}; (2b)-Cl, C20H14C12O4, dimethyl 1,5-dichloro-4b,8b,8c,8d-tetrahydrodibenzo[a, f]cyclopropa[c,d]pentalene-8c,8d-dicarboxylate, Pna21. The dibenzobarrelene molecules all have geometries and dimensions similar to those of related materials. In particular, the orientations of the two ester groups in each molecule differ, one being in general almost fully conjugated with the C(11)=C(12) double bond and the other almost non-conjugated. Relationships are sought between the ratios of the two regioisomeric photoproducts and molecular and crystal structures; both electronic and steric effects are considered, but no one effect seems to dominate.

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Vasil’eva, I. A. "Fine-Structure Fluorescence of Conjugated Chain Molecules." Optics and Spectroscopy 98, no. 5 (2005): 753. http://dx.doi.org/10.1134/1.1929062.

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BAI, PING, CHEE CHING CHONG, ER PING LI, and ZHIKUAN CHEN. "A MOLECULAR DIODE BASED ON CONJUGATED CO-OLIGOMERS." International Journal of Nanoscience 05, no. 04n05 (August 2006): 535–40. http://dx.doi.org/10.1142/s0219581x06004759.

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A molecular diode based on a conjugated co-oligomer composed of p-type and n-type segments is investigated using the first principles method. The co-oligomer is connected to Au electrodes to form an Au –oligomer– Au system. The infinite system is dealt with a finite structure confined in a device region and effects from semi-infinite electrodes. Density functional theory and nonequilibrium Green's function are used to describe the device region self-consistently. The current–voltage (I–V) characteristics of the constructed system are calculated and a rectification behavior is observed. The energy gap and the spatial orientation of molecular orbitals, and the transmission functions are calculated to analyze the I–V characteristics of the molecular diode.

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Wang, Gunuk, Tae-Wook Kim, Yun Hee Jang, and Takhee Lee. "Effects of Metal−Molecule Contact and Molecular Structure on Molecular Electronic Conduction in Nonresonant Tunneling Regime: Alkyl versus Conjugated Molecules." Journal of Physical Chemistry C 112, no. 33 (August 2008): 13010–16. http://dx.doi.org/10.1021/jp8048857.

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Huang, Ji, Huiling Gu, Na Li, Hua Yang, Gang Chen, Lizhu Zhang, Chengjun Dong, and Hongtao Guan. "Polypyrrole/Schiff Base Composite as Electromagnetic Absorbing Material with High and Tunable Absorption Performance." Molecules 27, no. 19 (September 20, 2022): 6160. http://dx.doi.org/10.3390/molecules27196160.

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In recent years, Schiff base-related conjugated systems have received extensive attention, but little research has been done in the field of electromagnetic materials. In this work, an organic conjugated system based on polypyrrole/hydrazone Schiff base (PPy/HSB) composites was constructed via a Schiff base synthetic route and their electromagnetic behavior was investigated. The electromagnetic response of PPy/HSB complexes demonstrates fine electromagnetic absorption performance. When the filler loading is 30 wt% in a paraffin matrix, an absorption peak of −43.1 dB was achieved and its effective absorption bandwidth (EAB) was located in the range of 10.88−18.0 GHz. The electromagnetic response behavior of PPy/HSB complexes is explained by models involving electronic structure, multi-polarization and conductive network. The mechanisms of PPy/HSB complexes formation and HSB crystallization are also discussed through the compatibility of PPy/HSB and the structure of HSB. Moreover, the morphology transformation of HSB in the PPy/HSB systems has been studied. This study opens the exploration of organic–dielectric conjugated systems in the field of electromagnetic materials, and significantly broadens the application range of organic–dielectric–dielectric composites.

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Cachaneski-Lopes, João P., and Augusto Batagin-Neto. "Effects of Mechanical Deformation on the Opto-Electronic Responses, Reactivity, and Performance of Conjugated Polymers: A DFT Study." Polymers 14, no. 7 (March 26, 2022): 1354. http://dx.doi.org/10.3390/polym14071354.

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The development of polymers for optoelectronic applications is an important research area; however, a deeper understanding of the effects induced by mechanical deformations on their intrinsic properties is needed to expand their applicability and improve their durability. Despite the number of recent studies on the mechanochemistry of organic materials, the basic knowledge and applicability of such concepts in these materials are far from those for their inorganic counterparts. To bring light to this, here we employ molecular modeling techniques to evaluate the effects of mechanical deformations on the structural, optoelectronic, and reactivity properties of traditional semiconducting polymers, such as polyaniline (PANI), polythiophene (PT), poly (p-phenylene vinylene) (PPV), and polypyrrole (PPy). For this purpose, density functional theory (DFT)-based calculations were conducted for the distinct systems at varied stretching levels in order to identify the influence of structural deformations on the electronic structure of the systems. In general, it is noticed that the elongation process leads to an increase in electronic gaps, hypsochromic effects in the optical absorption spectrum, and small changes in local reactivities. Such changes can influence the performance of polymer-based devices, allowing us to establish significant structure deformation response relationships.

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Shimoga, Ganesh, Ramasubba Reddy Palem, Dong-Soo Choi, Eun-Jae Shin, Pattan-Siddappa Ganesh, Ganesh Dattatraya Saratale, Rijuta Ganesh Saratale, Soo-Hong Lee, and Sang-Youn Kim. "Polypyrrole-Based Metal Nanocomposite Electrode Materials for High-Performance Supercapacitors." Metals 11, no. 6 (June 1, 2021): 905. http://dx.doi.org/10.3390/met11060905.

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Metallic nanostructures (MNs) and metal-organic frameworks (MOFs) play a pivotal role by articulating their significance in high-performance supercapacitors along with conducting polymers (CPs). The interaction and synergistic pseudocapacitive effect of MNs with CPs have contributed to enhance the specific capacitance and cyclic stability. Among various conjugated heterocyclic CPs, polypyrrole (PPy) (prevalently knows as “synthetic metal”) is exclusively studied because of its excellent physicochemical properties, ease of preparation, flexibility in surface modifications, and unique molecular structure–property relationships. Numerous researchers attempted to improve the low electronic conductivity of MNs and MOFs, by incorporating conducting PPy and/or used decoration strategy. This was succeeded by fine-tuning this objective, which managed to get outstanding supercapacitive performances. This brief technical note epitomizes various PPy-based metallic hybrid materials with different nano-architectures, emphasizing its technical implications in fabricating high-performance electrode material for supercapacitor applications.

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Ignashevich, Anna N., Elena V. Shklyaeva, and Georgy G. Abashev. "Synthesis and ue of ethylendoxythiophene and its substitutes. (Overview)." Вестник Пермского университета. Серия «Химия» = Bulletin of Perm University. CHEMISTRY 10, no. 3 (2020): 300–317. http://dx.doi.org/10.17072/2223-1838-2020-3-300-317.

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This review presents various synthetic approaches to 3,4-ethylenedioxythiophene (EDOT) and its derivatives. EDOT-based polymer (PEDOT) is one of the most widely used electroconducting high molecular weight heterocyclic compounds and it is often referred as the gold standard of electroconducting p-conjugated polymers. It is well known that embedding of substituents of different nature into the structure of any organic compound affects its properties. Thereby it is of undoubted interest to search new synthetic approaches with an aim to obtain EDOT-based monomers for the further preparation of conducting oligomers, polymers, and copolymers as potential materials for creating organic electronic devices.

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Smith, Matthew K., Thomas L. Bougher, Kyriaki Kalaitzidou, and Baratunde A. Cola. "Melt-processed P3HT and PE Polymer Nanofiber Thermal Conductivity." MRS Advances 2, no. 58-59 (2017): 3619–26. http://dx.doi.org/10.1557/adv.2017.499.

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ABSTRACT Thermal management is a growing challenge for electronics packaging because of increased heat fluxes and device miniaturization. Thermal interface materials (TIMs) are used in electronic devices to transfer heat between two adjacent surfaces. TIMs need to exhibit high thermal conductivity and must be soft to minimize thermal contact resistance. Polymers, despite their relative softness, suffer from low thermal conductivity (∼0.2 W/m-K). To overcome this challenge, we infiltrate nanoporous anodic aluminum oxide (AAO) templates with molten polymer to fabricate large area arrays of vertically aligned polymer nanofibers. Nanoscale confinement effects and flow induced chain elongation improve polymer chain alignment (measured using polarized Raman spectroscopy) and thermal conductivity (measured using the photoacoustic method) along the fiber’s long axis. Conjugated poly(3-hexylthiophene-2,5-diyl) (P3HT) and non- conjugated polyethylene (PE) of various molecular weights are explored to establish a relationship between polymer structure, nanofiber diameter, and the resulting thermal conductivity. In general, thermal conductivity improves with decreasing fiber diameter and increasing polymer molecular weight. Thermal conductivity of approximately 7 W/m-K was achieved for both the ∼200 nm diameter HDPE fibers and the 100 nm diameter P3HT fibers. These results pave the way for optimization of the processing conditions to produce high thermal conductivity fiber arrays using different polymers, which could potentially be used in thermal interface applications.

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Ohsato, Haruka, Shigeyuki Yamada, Motohiro Yasui, and Tsutomu Konno. "Effects of Tetrafluorocyclohexa-1,3-Diene Ring Position on Photoluminescence and Liquid-Crystalline Properties of Tricyclic π-Conjugated Molecules." Crystals 13, no. 8 (August 3, 2023): 1208. http://dx.doi.org/10.3390/cryst13081208.

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Tetrafluorocyclohexa-1,3-diene ring-containing tricyclic π-conjugated molecules are promising negative-dielectric-anisotropy guest species for vertical-alignment-type liquid-crystalline (LC) displays. Building on our previous work reporting the excellent photoluminescence (PL) properties of tricyclic π-conjugated molecules with central tetrafluorocyclohexa-1,3-diene rings, we herein synthesized four analogous molecules with terminal tetrafluorocyclohexa-1,3-diene rings from commercially available precursors and investigated the effects of substituent type and diene ring position on PL and LC properties using microscopic and spectroscopic methods. One of the prepared molecules exhibited a relatively planar molecular structure and formed herringbone-type aggregates via π/F and CH/π interactions instead of forming stacked aggregates via π/π stacking interactions, thus exhibiting relatively strong PL in solution and crystalline states. Moreover, the PL color of this compound depended on the electronic character of its terminal substituents along the long molecular axis. Of the four prepared species, two featured terminal ethyl groups and formed one or more LC phases. The PL properties of these phases indicated that the related phase transition induced changes in the aggregate structure, PL wavelength, and PL color. Our results expand the applicability of CF2CF2 moiety-containing tricyclic compounds as functional molecules for the fabrication of next-generation PL, LC, and PL-LC materials.

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Karabag, Aliekber, Dilek Soyler, Yasemin Arslan Udum, Levent Toppare, Gorkem Gunbas, and Saniye Soylemez. "Building Block Engineering toward Realizing High-Performance Electrochromic Materials and Glucose Biosensing Platform." Biosensors 13, no. 7 (June 25, 2023): 677. http://dx.doi.org/10.3390/bios13070677.

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The molecular engineering of conjugated systems has proven to be an effective method for understanding structure–property relationships toward the advancement of optoelectronic properties and biosensing characteristics. Herein, a series of three thieno[3,4-c]pyrrole-4,6-dione (TPD)-based conjugated monomers, modified with electron-rich selenophene, 3,4-ethylenedioxythiophene (EDOT), or both building blocks (Se-TPD, EDOT-TPD, and EDOT-Se-TPD), were synthesized using Stille cross-coupling and electrochemically polymerized, and their electrochromic properties and applications in a glucose biosensing platform were explored. The influence of structural modification on electrochemical, electronic, optical, and biosensing properties was systematically investigated. The results showed that the cyclic voltammograms of EDOT-containing materials displayed a high charge capacity over a wide range of scan rates representing a quick charge propagation, making them appropriate materials for high-performance supercapacitor devices. UV-Vis studies revealed that EDOT-based materials presented wide-range absorptions, and thus low optical band gaps. These two EDOT-modified materials also exhibited superior optical contrasts and fast switching times, and further displayed multi-color properties in their neutral and fully oxidized states, enabling them to be promising materials for constructing advanced electrochromic devices. In the context of biosensing applications, a selenophene-containing polymer showed markedly lower performance, specifically in signal intensity and stability, which was attributed to the improper localization of biomolecules on the polymer surface. Overall, we demonstrated that relatively small changes in the structure had a significant impact on both optoelectronic and biosensing properties for TPD-based donor–acceptor polymers.

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Sato, Ryoya, and Masaki Matsuda. "Formation of Three-Dimensional Electronic Networks Using Axially Ligated Metal Phthalocyanines as Stable Neutral Radicals." Crystals 10, no. 9 (August 24, 2020): 747. http://dx.doi.org/10.3390/cryst10090747.

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Organic π-radical crystals are potential single-component molecular conductors, as they involve charge carriers. We fabricated new organic π-radical crystals using axially ligated metal phthalocyanine anions ([MIII(Pc)L2]−) as starting materials. Electrochemical oxidation of [MIII(Pc)L2]− afforded single crystals of organic π-radicals of the type MIII(Pc)Cl2·THF (M = Co or Fe, THF = tetrahydrofuran), where the π-conjugated macrocyclic phthalocyanine ligand is one-electron oxidized. The X-ray crystal structure analysis revealed that MIII(Pc)Cl2 formed three-dimensional networks with π-π overlaps. The electrical resistivities of CoIII(Pc)Cl2·THF and FeIII(Pc)Cl2·THF at room temperature along the a-axis were 6 × 102 and 6 × 103 Ω cm, respectively, and were almost isotropic, meaning that MIII(Pc)Cl2·THF had three-dimensional electronic systems.

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29

Huang, Chenjiao, Wenwen Bao, Senhe Huang, Bin Wang, Chenchen Wang, Sheng Han, Chenbao Lu, and Feng Qiu. "Asymmetric Push–Pull Type Co(II) Porphyrin for Enhanced Electrocatalytic CO2 Reduction Activity." Molecules 28, no. 1 (December 24, 2022): 150. http://dx.doi.org/10.3390/molecules28010150.

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Molecular electrocatalysts for electrochemical carbon dioxide (CO2) reduction has received more attention both by scientists and engineers, owing to their well-defined structure and tunable electronic property. Metal complexes via coordination with many π-conjugated ligands exhibit the unique electrocatalytic CO2 reduction performance. The symmetric electronic structure of this metal complex may play an important role in the CO2 reduction. In this work, two novel dimethoxy substituted asymmetric and cross-symmetric Co(II) porphyrin (PorCo) have been prepared as the model electrocatalyst for CO2 reduction. Owing to the electron donor effect of methoxy group, the intramolecular charge transfer of these push–pull type molecules facilitates the electron mobility. As electrocatalysts at −0.7 V vs. reversible hydrogen electrode (RHE), asymmetric methoxy-substituted Co(II) porphyrin shows the higher CO2-to-CO Faradaic efficiency (FECO) of ~95 % and turnover frequency (TOF) of 2880 h−1 than those of control materials, due to its push–pull type electronic structure. The density functional theory (DFT) calculation further confirms that methoxy group could ready to decrease to energy level for formation *COOH, leading to high CO2 reduction performance. This work opens a novel path to the design of molecular catalysts for boosting electrocatalytic CO2 reduction.

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Weldeab, Asmerom O., Cory T. Kornman, Lei Li, Daken J. Starkenburg, Xueying Zhao, Danielle E. Fagnani, Sara J. Sadovy, Scott S. Perry, Jiangeng Xue, and Ronald K. Castellano. "Structure–Assembly–Property Relationships of Simple Ditopic Hydrogen-Bonding-Capable π-Conjugated Oligomers." Organic Materials 03, no. 02 (April 2021): 302–16. http://dx.doi.org/10.1055/a-1534-1508.

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A series of simple ditopic hydrogen-bonding-capable molecules functionalized with 2,4-diamino-1,3,5-triazine (DAT), barbiturate (B), and phthalhydrazide (PH) on both termini of a 2,2′-bithiophene linker were designed and synthesized. The intrinsic electronic structures of the ditopic DAT, PH, and B molecules were investigated with ground-state density functional theory calculations. Their solution absorbance was investigated with UV-vis, where it was found that increasing size of R group substituents on the bithiophene linker resulted in a general blue-shift in solution absorbance maximum. The solid-state optical properties of ditopic DAT and B thin films were evaluated by UV-vis, and it was found that the solid-state absorbance was red-shifted with respect to solution absorbance in all cases. The three DAT molecules were vacuum-thermal-deposited onto Au(111) substrates and the morphologies were examined using scanning tunneling microscopy. (DAT-T)2 was observed to organize into six-membered rosettes on the surface, whereas (DAT-TMe)2 formed linear assemblies before and after thermal annealing. For (DAT-Toct)2 , an irregular arrangement was observed, while (B-TMe)2 showed several co-existent assembly patterns. The work presented here provides fundamental molecular–supramolecular relationships useful for semiconductive materials design based on ditopic hydrogen-bonding-capable building blocks.

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Vacareanu, Loredana, Teofilia Ivan, and Mircea Grigoras. "New symmetrical conjugated thiophene-azomethines containing triphenylamine or carbazole units: Synthesis, thermal and optoelectrochemical properties." High Performance Polymers 24, no. 8 (July 18, 2012): 717–29. http://dx.doi.org/10.1177/0954008312450595.

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New oligo- and poly(azomethine)s containing 3,4-dicyanothiophene and triphenylamine or carbazole units were synthesized under condensation reaction conditions. Although the different amino group reactivity, a one-pot synthesis of symmetric conjugated oligoazomethines was possible by judicious choice of solvent and careful control of reagent stoichiometry. Different polycondensation strategies (in solution and bulk polymerization reactions) were applied in order to obtain soluble oligoazomethines and poly(azomethine)s. Their expected chemical structures were confirmed by 1H-NMR and Fourier transform infrared (FT-IR) characterization techniques. Electronic properties of the synthesized oligoazomethines were investigated in different solvents, using UV-Vis and photoluminescence spectroscopy (PL) and these revealed that there is a slight dependency between the solvent polarity and absorption wavelength, while the emissions peaks are shifted at higher wavelength with increasing the solvent polarity. The thermogravimetric and differential scanning calorimetry analysis showed a high thermal stability up to 350 °C and no glass transition temperature. Having in their structure electroactive sites, i.e., carbazole and triphenylamine units, cyclic voltammetry technique was used to investigate the oxido-reduction behavior and to determine the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels.

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Thurston, Bryce A., Ethan P. Shapera, John D. Tovar, André Schleife, and Andrew L. Ferguson. "Revealing the Sequence-Structure–Electronic Property Relation of Self-Assembling π-Conjugated Oligopeptides by Molecular and Quantum Mechanical Modeling." Langmuir 35, no. 47 (October 28, 2019): 15221–31. http://dx.doi.org/10.1021/acs.langmuir.9b02593.

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Anggraini, Yunita, and Inge Magdalena Sutjahja. "Analysis of Biphenylene and Benzo{3,4}cyclobuta{1,2-c}thiophene Molecular Orbital Structure using the Huckel Method." Revista de Chimie 72, no. 3 (July 29, 2021): 198–209. http://dx.doi.org/10.37358/rc.21.3.8448.

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The Huckel method is an old fashion method to predict the molecular orbital and energies of  electrons in a conjugated molecule. Although Huckel`s theory`s approximations are relatively crude, its general results are still reasonable compared to the advanced computing method and experimental results for many molecules. This paper describes the Huckel calculation of biphenylene and benzo{3,4}cyclobuta{1,2-c}thiophene using the HuLis software. The benzo{3,4}cyclobuta{1,2-c}thiophene is a derivative of biphenylene, in which case one of the benzene rings is replaced by a thiophene ring. This change produces new electronic properties that are interesting to study. This work focused on calculating those molecules on energy levels diagrams, linear combination coefficient of molecular orbitals, molecular orbital shape, energy gap, resonance energy, bond-order, bond length, and charge distribution (π electron population). Besides, we calculate the harmonic oscillator measure of aromaticity (HOMA) parameter to study the Huckel method`s validity.

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Savagatrup, Suchol, Aditya S. Makaram, Daniel J. Burke, and Darren J. Lipomi. "Mechanical Properties of Conjugated Polymers and Polymer-Fullerene Composites as a Function of Molecular Structure." Advanced Functional Materials 24, no. 8 (October 14, 2013): 1169–81. http://dx.doi.org/10.1002/adfm.201302646.

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Savagatrup, Suchol, Aditya S. Makaram, Daniel J. Burke, and Darren J. Lipomi. "Mechanical Properties of Conjugated Polymers and Polymer-Fullerene Composites as a Function of Molecular Structure." Advanced Functional Materials 24, no. 16 (April 2014): 2264. http://dx.doi.org/10.1002/adfm.201400595.

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Sun, Tao, Zong-Jun Li, and Xin-Bo Zhang. "Achieving of High Density/Utilization of Active Groups via Synergic Integration of C=N and C=O Bonds for Ultra-Stable and High-Rate Lithium-Ion Batteries." Research 2018 (December 16, 2018): 1–10. http://dx.doi.org/10.1155/2018/1936735.

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Organic electrode materials are receiving ever-increasing research interest due to their combined advantages, including resource renewability, low cost, and environmental friendliness. However, their practical applications are still terribly plagued by low conductivity, poor rate capability, solubility in electrolyte, and low density/utilization of active groups. In response, herein, as a proof-of-concept experiment, C=N and C=O bonds are synergically integrated into the backbone of pentacene to finely tune the electronic structures of pentacene. Unexpectedly, the firstly obtained unique 5,7,11,14-tetraaza-6,13-pentacenequinone/reduced graphene oxide (TAPQ/RGO) composite exhibits superior electrochemical performances, including an ultra-stable cycling stability (up to 2400 cycles) and good rate capability (174 mAh g−1 even at a high current density of 3.2 A g−1), which might be attributed to the abundant active groups, π-conjugated molecular structure, leaf-like morphology, and the interaction between TAPQ and graphene.

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Liu, Ziyu, Tingting Hu, Muwafag Osman Adam Balila, Jihui Zhang, Yujin Zhang, and Wei Hu. "Investigation of SERS and Electron Transport Properties of Oligomer Phenylacetyne-3 Trapped in Gold Junctions." Nanomaterials 12, no. 3 (February 7, 2022): 571. http://dx.doi.org/10.3390/nano12030571.

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Molecular junctions hold great potential for future microelectronics and attract people’s attention. Here, we used density functional theory calculations (DFT) to investigate the surface-enhanced Raman spectroscopy (SERS) and electron transport properties of fully π-conjugated oligomers (phenylacetylene)-3 (OPE-3) trapped in gold junctions. The effects of charge injection, an applied electric field, and molecular deformation are considered. We found that a new Raman peak located at around 1400 cm−1 appears after the injection of a charge, which agrees well with the experiment. The external electric field and configurational deformation hardly affect the Raman spectra, indicating that the electronic rather than the geometrical structure determines the Raman response. Nonequilibrium Green’s function (NEGF) calculations show that both the rotation of the benzene groups and an increased electrode distance largely reduced the conductivity of the studied molecular junctions. The present investigations provide valuable information on the effect of charging, electric field, and deformation on the SERS and conductivity of molecular junctions, helping the development of molecular devices.

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38

Al-Azzawi, Ahmed G. S., Shujahadeen B. Aziz, Elham M. A. Dannoun, Ahmed Iraqi, Muaffaq M. Nofal, Ary R. Murad, and Ahang M. Hussein. "A Mini Review on the Development of Conjugated Polymers: Steps towards the Commercialization of Organic Solar Cells." Polymers 15, no. 1 (December 29, 2022): 164. http://dx.doi.org/10.3390/polym15010164.

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This review article covers the synthesis and design of conjugated polymers for carefully adjusting energy levels and energy band gap (EBG) to achieve the desired photovoltaic performance. The formation of bonds and the delocalization of electrons over conjugated chains are both explained by the molecular orbital theory (MOT). The intrinsic characteristics that classify conjugated polymers as semiconducting materials come from the EBG of organic molecules. A quinoid mesomeric structure (D-A D+ = A−) forms across the major backbones of the polymer as a result of alternating donor–acceptor segments contributing to the pull–push driving force between neighboring units, resulting in a smaller optical EBG. Furthermore, one of the most crucial factors in achieving excellent performance of the polymer is improving the morphology of the active layer. In order to improve exciton diffusion, dissociation, and charge transport, the nanoscale morphology ensures nanometer phase separation between donor and acceptor components in the active layer. It was demonstrated that because of the exciton’s short lifetime, only small diffusion distances (10–20 nm) are needed for all photo-generated excitons to reach the interfacial region where they can separate into free charge carriers. There is a comprehensive explanation of the architecture of organic solar cells using single layer, bilayer, and bulk heterojunction (BHJ) devices. The short circuit current density (Jsc), open circuit voltage (Voc), and fill factor (FF) all have a significant impact on the performance of organic solar cells (OSCs). Since the BHJ concept was first proposed, significant advancement and quick configuration development of these devices have been accomplished. Due to their ability to combine great optical and electronic properties with strong thermal and chemical stability, conjugated polymers are unique semiconducting materials that are used in a wide range of applications. According to the fundamental operating theories of OSCs, unlike inorganic semiconductors such as silicon solar cells, organic photovoltaic devices are unable to produce free carrier charges (holes and electrons). To overcome the Coulombic attraction and separate the excitons into free charges in the interfacial region, organic semiconductors require an additional thermodynamic driving force. From the molecular engineering of conjugated polymers, it was discovered that the most crucial obstacles to achieving the most desirable properties are the design and synthesis of conjugated polymers toward optimal p-type materials. Along with plastic solar cells (PSCs), these materials have extended to a number of different applications such as light-emitting diodes (LEDs) and field-effect transistors (FETs). Additionally, the topics of fluorene and carbazole as donor units in conjugated polymers are covered. The Stille, Suzuki, and Sonogashira coupling reactions widely used to synthesize alternating D–A copolymers are also presented. Moreover, conjugated polymers based on anthracene that can be used in solar cells are covered.

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39

Yu, Hao, Danielle L. Gray, Toby J. Woods, and Jeffrey S. Moore. "Trioxazolo[2³]metacyclophane: synthesis, structural analysis, and optical properties." Acta Crystallographica Section C Structural Chemistry 78, no. 2 (January 18, 2022): 81–87. http://dx.doi.org/10.1107/s2053229622000298.

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The synthesis and characterization of the conjugated macrocycle trioxazolo[23]metacyclophane, C27H15N3O3 (M), is reported. The macrocycle was synthesized in three steps by the multicomponent van Leusen reaction and consists of meta-linked phenylenes connected through positions 4 and 5 of an oxazole heterocyclic ring. The molecular structure was investigated by NMR spectroscopy, mass spectrometry, gel permeation chromatography (GPC), and single-crystal X-ray crystallography. X-ray diffraction (XRD) analysis shows that M possesses a twisted saddle-like shape and interacts with nearby molecules by various π–π interactions. Absorption and emission spectroscopy and density functional theory (DFT) calculations were further used to study the electronic properties of M.

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40

Mohamed, Mohamed Gamal, Tharwat Hassan Mansoure, Maha Mohamed Samy, Yasuno Takashi, Ahmed A. K. Mohammed, Tansir Ahamad, Saad M. Alshehri, et al. "Ultrastable Conjugated Microporous Polymers Containing Benzobisthiadiazole and Pyrene Building Blocks for Energy Storage Applications." Molecules 27, no. 6 (March 21, 2022): 2025. http://dx.doi.org/10.3390/molecules27062025.

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In recent years, conjugated microporous polymers (CMPs) have become important precursors for environmental and energy applications, compared with inorganic electrode materials, due to their ease of preparation, facile charge storage process, π-conjugated structures, relatively high thermal and chemical stability, abundance in nature, and high surface areas. Therefore, in this study, we designed and prepared new benzobisthiadiazole (BBT)-linked CMPs (BBT–CMPs) using a simple Sonogashira couplings reaction by reaction of 4,8-dibromobenzo(1,2-c;4,5-c′)bis(1,2,5)thiadiazole (BBT–Br2) with ethynyl derivatives of triphenylamine (TPA-T), pyrene (Py-T), and tetraphenylethene (TPE-T), respectively, to afford TPA–BBT–CMP, Py–BBT–CMP, and TPE–BBT–CMP. The chemical structure and properties of BBT–CMPs such as surface areas, pore size, surface morphologies, and thermal stability using different measurements were discussed in detail. Among the studied BBT–CMPs, we revealed that TPE–BBT–CMP displayed high degradation temperature, up to 340 °C, with high char yield and regular, aggregated sphere based on thermogravimetric analysis (TGA) and scanning electron microscopy (SEM), respectively. Furthermore, the Py–BBT–CMP as organic electrode showed an outstanding specific capacitance of 228 F g–1 and superior capacitance stability of 93.2% (over 2000 cycles). Based on theoretical results, an important role of BBT–CMPs, due to their electronic structure, was revealed to be enhancing the charge storage. Furthermore, all three CMP polymers featured a high conjugation system, leading to improved electron conduction and small bandgaps.

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41

Heimel, Georg, Lorenz Romaner, Egbert Zojer, and Jean-Luc Brédas. "Toward Control of the Metal−Organic Interfacial Electronic Structure in Molecular Electronics: A First-Principles Study on Self-Assembled Monolayers of π-Conjugated Molecules on Noble Metals." Nano Letters 7, no. 4 (April 2007): 932–40. http://dx.doi.org/10.1021/nl0629106.

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42

El Maliki, Z., M. Bouachrine, M. Hamidi, L. Bejjit, and M. Haddad. "Theoretical Studies on the Structural, Electronic and Optical Properties of the New π-conjugated Copolymers Based on Carbazole and Thiophene." Journal of Scientific Research 4, no. 1 (December 24, 2011): 119. http://dx.doi.org/10.3329/jsr.v4i1.7450.

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This work reports a theoretical investigation of π-conjugated oligomers constituted by n units (n = 1-4) based on carbazole and ethylenedioxythiophene. The molecular geometry, torsional potential, electronic and optical properties of the oligomers [Cbz-(Edot)n-Cbz] (n = 1-4) are investigated using DFT (B3LYP/3-21G*) calculations. The discussion is focused on the influence of chain length on the properties of these copolymers. The analyses of torsional angles for [Cbz-(Edot)4-Cbz] reveal that the structure has a anti-planar conformation. The electronic properties of the molecules, HOMO, LUMO and Eg (HOMO-LUMO), are studied using B3LYP functional. The results have been compared with those of thiophene and ethylenedioxythiophene. The lowest excitation energies (Eex) and the maximal absorption wavelength (λabs) are studied using the TD/DFT, ZINDO and CIS methods. The electronic transitions of the absorption spectrum derived by TD/DFT method give useful structural and electronic information for designing novel conducting organic polymer materials. The bridging effect by C=C(CN)2 on the optoelectronic properties of the (carbazole-thiophene-carbazole) comonomer is investigated. Keywords: Conducting polymer; Carbazole-(Ethylenedioxythiophene)n-Carbazole comonomers; DFT Optoelectronic properties; absorption coefficient; Bridging effect. © 2012 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. doi: http://dx.doi.org/10.3329/jsr.v4i1.7450J. Sci. Res. 4 (1), 119-133 (2012)

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Pandit, Bill, Nicholas E. Jackson, Tianyue Zheng, Thomas J. Fauvell, Eric F. Manley, Meghan Orr, Samantha Brown-Xu, Luping Yu, and Lin X. Chen. "Molecular Structure Controlled Transitions between Free-Charge Generation and Trap Formation in a Conjugated Copolymer Series." Journal of Physical Chemistry C 120, no. 8 (February 19, 2016): 4189–98. http://dx.doi.org/10.1021/acs.jpcc.5b10291.

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44

Demir, Nuriye, Gul Yakali, Merve Karaman, Yenal Gokpek, Serpil Denizalti, Hakan Bilgili, Bircan Dindar, Seraffetin Demic, and Mustafa Can. "Structure–Property Relationship in π-Conjugated Bipyridine Derivatives: Effect of Acceptor and Donor Moieties on Molecular Behavior." Journal of Physical Chemistry C 123, no. 36 (August 15, 2019): 21998–2008. http://dx.doi.org/10.1021/acs.jpcc.9b05894.

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45

Wei, Shuxian, Xiaoqing Lu, Xiaofan Shi, Zhigang Deng, Yang Shao, Lianming Zhao, Wenyue Guo, and Chi-Man Lawrence Wu. "Theoretical Insight into Organic Dyes Incorporating Triphenylamine-Based Donors and Binaryπ-Conjugated Bridges for Dye-Sensitized Solar Cells." International Journal of Photoenergy 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/280196.

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The design of light-absorbent sensitizers with sustainable and environment-friendly material is one of the key issues for the future development of dye-sensitized solar cells (DSSCs). In this work, a series of organic sensitizers incorporating alkoxy-substituted triphenylamine (tpa) donors and binaryπ-conjugated bridges were investigated using density functional theory (DFT) and time-dependent DFT (TD-DFT). Molecular geometry, electronic structure, and optical absorption spectra are analyzed in the gas phase, chloroform, and dimethylformamide (DMF) solutions. Our results show that properly choosing the heteroaromatic atoms and/or adding one more alkoxy-substituted tpa group can finely adjust the molecular orbital energy. The solvent effect renders the HOMO-LUMO gaps of the tpa-based sensitizers decrease in the sequence of DMF solution < chloroform solution < gas phase. The absorption spectra are assigned to the ligand-to-ligand charge transfer (LLCT) characteristics via transitions mainly from tpa, 3,4-ethylenedioxythiophene (edot), and alkyl-substituted dithienosilole (dts) groups to edot, dts, and cyanoacrylic acid groups. The binaryπ-conjugated bridges play different roles in balancing the electron transfer and recombination for the different tpa-based sensitizers. The protonation/deprotonation effect has great effect on the HOMO-LUMO gaps and thus has great influence on the bands at the long wavelength region, but little influence on the bands at the short wavelength region.

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Jeong, Youngdo, Seungwook Kwon, Yongku Kang, Changjin Lee, Eisuke Ito, Masahiko Hara, and Jaegeun Noh. "Unique domain structure of π-conjugated tolanethioacetate self-assembled monolayers on Au(111)." Ultramicroscopy 107, no. 10-11 (October 2007): 1000–1003. http://dx.doi.org/10.1016/j.ultramic.2007.02.038.

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JEONG, JEON WOO, YOUNGHWAN KWON, JEONG JU BAEK, LEE SOON PARK, EUI-WAN LEE, YOON SOO HAN, and HONG TAK KIM. "SYNTHESIS AND ELECTROLUMINESCENT PROPERTIES OF POLYAZOMETHINE-TYPE CONJUGATED POLYMERS CONTAINING HETEROCYCLIC PHENOTHIAZINE AND CARBAZOLE MOIETY." Journal of Nonlinear Optical Physics & Materials 14, no. 04 (December 2005): 545–53. http://dx.doi.org/10.1142/s0218863505003006.

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Polyazomethine-type conjugated polymers were synthesized by Schiff-base reaction. One was poly(PZ-PBI) with alternating phenothiazine (PZ) and azomethine units (-C = N-) , and the other was poly(CZ-PBI) comprising alternating carbazole (CZ) and azomethine groups. Conjugated polymers exhibited improved solubility in common organic solvents due to alkyl side chains on phenothiazine and carbazole rings as well as polar azomethine groups in main chains. Single- and double-layer PLEDs were fabricated. Their electroluminescent properties were studied from the viewpoint of polymer structure vs. emission color and efficiency.

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SCHNEIDER-POLLACK, SAMANTHA, MONA DOSHI, JEFF GELDMEIER, and ANDRE J. GESQUIERE. "P3HT CHAIN MORPHOLOGY IN COMPOSITE P3HT/PCBM NANOPARTICLES STUDIED BY SINGLE PARTICLE FLUORESCENCE EXCITATION POLARIZATION SPECTROSCOPY." Biophysical Reviews and Letters 08, no. 03n04 (December 2013): 243–53. http://dx.doi.org/10.1142/s1793048013500082.

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The use of conjugated polymers such as poly(3-hexylthiophene) (P3HT) in the active layers of plastic electronic devices could provide a more practical and accessible form of energy production and storage. The efficiency of these devices is intimately connected to the morphology of the polymer chains in the active layer materials, as polymer folding affects mesoscale material morphology. The latter in turn influences electronic structure and thus performance of the active layer. It is, however, highly challenging to determine molecular structure and folding properties in a bulk material. Here, it is shown that through the use of nanoparticles as a model system for the bulk material insight in molecular morphology can be gained through single particle fluorescence excitation spectroscopy. The study of P3HT chain morphologies was accomplished through the investigation of neat (0 wt% PCBM) P3HT nanoparticles and 25, 50 and 75 wt% PCBM blended P3HT nanoparticles. A striking discontinuous trend in P3HT chain morphology as a function of PCBM blending ratio was observed, where P3HT morphologies at 25 wt% and 75 wt% blending ratios appear to be more disordered than those observed for the 50 wt% blending ratio. These data suggest that at least from the morphological perspective, the 1:1 blending ratio appears to yield the better P3HT chain alignment. [Formula: see text]Special Issue Comment: This paper about solving single molecule conformations is related to the papers in this Special Issue on mathematical models for treatment of single molecule trajectories,1 nonblinking inorganic nanocrystals,2 and hybrid quantom dot–fullerence composite nanoparticles.3

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Postnikov, Valery A., Nataliya I. Sorokina, Artem A. Kulishov, Maria S. Lyasnikova, Vadim V. Grebenev, Alexey E. Voloshin, Oleg V. Borshchev, et al. "Highly luminescent crystals of a novel linear π-conjugated thiophene–phenylene co-oligomer with a benzothiadiazole fragment." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 75, no. 6 (November 14, 2019): 1076–85. http://dx.doi.org/10.1107/s2052520619012484.

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The synthesis, growth from solutions and structure of crystals of a new linear thiophene–phenylene co-oligomer with a central benzothiadiazole fragment with a conjugated core, (TMS-2T-Ph)2-BTD, are presented. Single-crystal samples in the form of needles with a length of up to 7 mm were grown and their crystal structure was determined at 85 K and 293 K using single-crystal X-ray diffraction. The conformational differences between the crystal structures are insignificant. The parameters of melting and liquid crystalline phase transitions of (TMS-2T-Ph)2-BTD were established using differential scanning calorimetry and the thermal stability of the crystals was investigated using thermogravimetric analysis. The optical absorption and photoluminescence spectra of the solutions and crystals of (TMS-2T-Ph)2-BTD were obtained, and the kinetics of their photodegradation under the action of UV radiation were studied.

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Vilche, Anna, Roger Bujaldón, Xavier Alcobé, Dolores Velasco, and Cristina Puigjaner. "Powder X-ray diffraction as a powerful tool to exploit in organic electronics: shedding light on the first N,N′,N′′-trialkyldiindolocarbazole." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 78, no. 2 (March 29, 2022): 253–60. http://dx.doi.org/10.1107/s2052520622001858.

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Abstract:

The first crystal structure of a fully N-alkylated diindolocarbazole derivative, namely, 5,8,14-tributyldiindolo[3,2-b;2′,3′-h]carbazole (1, C36H39N3), has been determined from laboratory powder X-ray diffraction (PXRD) data. A complex trigonal structure with a high-volume unit cell of 12987 Å3 was found, with a very long a(=b) [52.8790 (14) Å] and a very short c [5.36308 (13) Å] unit-cell parameter (hexagonal setting). The detailed analysis of the intermolecular interactions observed in the crystal structure of 1 highlights its potential towards the implementation of this core as a semiconductor in organic thin-film transistor (OTFT) devices. Since the molecule has a flat configuration reflecting its π-conjugated system, neighbouring molecules are found to stack atop each other in a slipped parallel fashion via π–π stacking interactions between planes of ca 3.30 Å, with a centroid–centroid distance between the aromatic rings corresponding to the shortest axis of the unit cell (i.e. c). The alkylation of the three N atoms proves to be a decisive feature since it favours the presence of C—H...π interactions in all directions, which strengthens the crystal packing. As a whole, PXRD proves to be a valuable option for the resolution of otherwise inaccessible organic crystal structures of interest in different areas.

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Journal articles on the topic 'Pai-Conjugated Molecular Materials Electronic Structure'

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