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Journal articles on the topic 'Based QDs'

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Published: 4 June 2021
Last updated: 7 February 2022

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1

Miropoltsev, Maksim, Vera Kuznetsova, Anton Tkach, Sergei Cherevkov, Anastasiia Sokolova, Viktoria Osipova, Yulia Gromova, et al. "FRET-Based Analysis of AgInS2/ZnAgInS/ZnS Quantum Dot Recombination Dynamics." Nanomaterials 10, no. 12 (December 8, 2020): 2455. http://dx.doi.org/10.3390/nano10122455.

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Ternary quantum dots (QDs) are very promising nanomaterials with a range of potential applications in photovoltaics, light-emitting devices, and biomedicine. Despite quite intensive studies of ternary QDs over the last years, the specific relaxation channels involved in their emission mechanisms are still poorly understood, particularly in the corresponding core-shell nanostructures. In the present work, we have studied the recombination pathways of AgInS2 QDs stabilized with the ZnAgInS alloy layer and the ZnS shell (AIS/ZAIS/ZnS QDs) using time-resolved fluorescence spectroscopy. We have also investigated FRET in complexes of AIS/ZAIS/ZnS QDs and cyanine dyes with the absorption bands overlapping in the different regions of the QD emission spectrum, which allowed us to selectively quench the radiative transitions of the QDs. Our studies have demonstrated that FRET from QDs to dyes results in decreasing of all QD PL decay components with the shortest lifetime decreasing the most and the longest one decreasing the least. This research presents important approaches for the investigation of ternary QD luminescence mechanisms by the selective quenching of recombination pathways. These studies are also essential for potential applications of ternary QDs in photodynamic therapy, multiplex analysis, and time-resolved FRET sensing.
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2

Nowozin, Tobias, Michael Narodovitch, Leo Bonato, Dieter Bimberg, Mohammed N. Ajour, Khaled Daqrouq, and Abdullah Balamash. "Room-Temperature Hysteresis in a Hole-Based Quantum Dot Memory Structure." Journal of Nanotechnology 2013 (2013): 1–4. http://dx.doi.org/10.1155/2013/797964.

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We demonstrate a memory effect in self-assembled InAs/Al0.9Ga0.1As quantum dots (QDs) near room temperature. The QD layer is embedded into a modulation-doped field-effect transistor (MODFET) which allows to charge and discharge the QDs and read out the logic state of the QDs. The hole storage times in the QDs decrease from seconds at 200 K down to milliseconds at room temperature.
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3

Drbohlavová, Jana, Jana Chomoucka, Radim Hrdý, Vojtech Svatos, and Jaromir Hubalek. "Biosensing Surfaces Based on Quantum Dots Array." Applied Mechanics and Materials 490-491 (January 2014): 1602–6. http://dx.doi.org/10.4028/www.scientific.net/amm.490-491.1602.

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The fabrication of self-ordered semiconductor (TiO2) and noble metal (Au) QDs arrays was successfully achieved by advanced nonlithographic template based method, namely using nanoporous alumina template. The emphasis was placed on the successful preparation of QDs arrays with the desired size, homogeneous distribution and optical (especially fluorescence) properties. Titania and gold QDs characterization by SEM, EDX and fluorescence spectroscopy was performed in order to verify their surface topography, chemical composition and emission properties in UV/VIS range of spectra, respectively. The surface biofunctionalization of QDs was realized via simple physical adsorption of glutathione tripeptide, which makes these arrays suitable for potential biosensing application, mainly in optical and electrochemical detection of biomoleculesin vitro.
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4

Zhang, Tao, and Tim Liedl. "DNA-Based Assembly of Quantum Dots into Dimers and Helices." Nanomaterials 9, no. 3 (March 2, 2019): 339. http://dx.doi.org/10.3390/nano9030339.

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Owing to their unique optical properties, colloidal quantum dots (QDs) have attracted much attention as versatile fluorescent markers with broad biological and physical applications. On the other hand, DNA-based assembly has proven to be a powerful bottom-up approach to create designer nanoscale objects and to use these objects for the site-directed arrangement of guest components. To achieve good colloidal stability and accurate positioning of QDs on DNA templates, robust QD surface functionalization is crucial. Here, we present a simple and reliable conjugation method for the direct attachment of DNA molecules to QDs. Phosphorothiolated regions of chimera oligonucleotides are attached and incorporated into a ZnS layer freshly growing in situ on QDs that were rendered water soluble with hydrophilic ligands in a prior step. The reaction can be completed in a 2 mL plastic tube without any special equipment. The utility of these DNA-labeled QDs is demonstrated via prototypical assemblies such as QDs dimers with various spacings and chiral helical architectures.
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5

Zhao, Zhili, Xinzhong Wang, Kaidong Yang, Fang Fan, Dan Wu, Sheng Liu, and Kai Wang. "Analysis of Factors Affecting Optical Performance of GaN-Based Micro-LEDs with Quantum Dots Films." Crystals 10, no. 3 (March 14, 2020): 203. http://dx.doi.org/10.3390/cryst10030203.

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Optical performance in terms of light efficiency, color crosstalk and ambient contrast ratio were analyzed for blue GaN-based micro-light emitting diodes (micro-LEDs) combined with red/green quantum dots (QDs)-polymethyl methacrylate (PMMA) films. The thickness and mass ratio of QDs films are two critical factors in affecting the performance of micro-LEDs. Firstly, the precise optical modeling of QDs-PMMA films is established based on the double integrating sphere (DIS) testing system and inverse adding doubling algorithm (IADA) theory. Red and green QDs-PMMA films are composed of ZnCdSe/ZnS QDs and green ZnCdSeS/ZnS QDs, respectively. The fundamental optical parameters of QDs-PMMA films, including scattering, absorption and anisotropy coefficients, are obtained successfully. Secondly, based on these optical parameters, the Monte Carlo ray tracing method is applied to analyze the effect of a QDs-PMMA film’s thickness and mass ratio on the optical performance of micro-LEDs. Results reveal that the light efficiency first increases and then decreases with the increase of a QDs film’s thickness or mass ratio, owing to the scattering characteristics of QDs. Different from the variation tendencies of light efficiency, the crosstalk between adjacent pixels increases as the QDs-PMMA film’s thickness or mass ratio increases, and the ambient contrast ratio is kept stable when the thickness increases. The mass ratio variation of QDs film can change the optical performance of micro-LEDs more effectively than thickness, which demonstrates that mass ratio is a more important factor affecting the optical performance of micro-LEDs.
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6

Peng, Chun-Wei, and Yan Li. "Application of Quantum Dots-Based Biotechnology in Cancer Diagnosis: Current Status and Future Perspectives." Journal of Nanomaterials 2010 (2010): 1–11. http://dx.doi.org/10.1155/2010/676839.

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The semiconductor nanocrystal quantum dots (QDs) have excellent photo-physical properties, and the QDs-based probes have achieved encouraging developments in cellular and in vivo molecular imaging. More and more researches showed that QDs-based technology may become a promising approach in cancer research. In this review, we focus on recent application of QDs in cancer diagnosis and treatment, including early detection of primary tumor such as ovarian cancer, breast cancer, prostate cancer and pancreatic cancer, as well as regional lymph nodes and distant metastases. With the development of QDs synthesis and modification, the effect of QDs on tumor metastasis investigation will become more and more important in the future.
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7

Cao, Yunqing, Ping Zhu, Dongke Li, Xianghua Zeng, and Dan Shan. "Size-Dependent and Enhanced Photovoltaic Performance of Solar Cells Based on Si Quantum Dots." Energies 13, no. 18 (September 16, 2020): 4845. http://dx.doi.org/10.3390/en13184845.

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Recently, extensive studies have focused on exploring a variety of silicon (Si) nanostructures among which Si quantum dots (Si QDs) may be applied in all Si tandem solar cells (TSCs) for the time to come. By virtue of its size tunability, the optical bandgap of Si QDs is capable of matching solar spectra in a broad range and thus improving spectral response. In the present work, size-controllable Si QDs are successfully obtained through the formation of Si QDs/SiC multilayers (MLs). According to the optical absorption measurement, the bandgap of Si QDs/SiC MLs shows a red shift to the region of long wavelength when the size of dots increases, well conforming to quantum confinement effect (QCE). Additionally, heterojunction solar cells (HSCs) based on Si QDs/SiC MLs of various sizes are presented and studied, which demonstrates the strong dependence of photovoltaic performance on the size of Si QDs. The measurement of external quantum efficiency (EQE) reveals the contribution of Si QDs to the response and absorption in the ultraviolet–visible (UV-Vis) light range. Furthermore, Si QDs/SiC MLs-based solar cell shows the best power conversion efficiency (PCE) of 10.15% by using nano-patterned Si light trapping substrates.
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8

Istomina, M. S., N. A. Pechnikova, D. V. Korolev, E. I. Pochkayeva, D. S. Mazing, M. M. Galagudza, V. A. Moshnikov, and E. V. Shlyakhto. "ZAIS-based colloidal QDs as fluorescent labels for theranostics: physical properties, biodistribution and biocompatibility." NANOMEDICINE, no. 6 (December 24, 2018): 94–101. http://dx.doi.org/10.24075/brsmu.2018.073.

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In recent years there has been an increase in interest in the use of colloidal quantum dots (QDs) in biology and medicine. In particular, QDs can be a perspective nanoscale object for theranostics, in which due to the specific accumulation of drug-loaded QDs in the pathological focus, its simultaneous visualization and targeted therapeutic influence occur. One of the serious limitations of the use of QDs in medicine is their potential toxicity, especially when the nanocrystal material contains elements such as cadmium or plumbum. Therefore, it is promising to develop labels based on QDs of relatively less toxic semiconductors of group I-III-VI, such as CuInS2 and AgInS2. In this study, biodistribution and biocompatibility of QDs based on the AgInS2 compound with a ZnS shell (ZAIS) are considered. In the study of biodistribution, the accumulation of QDs in organs such as liver, lungs, heart and kidneys was revealed. It was shown that QDs in the dose range from 2 • 10–7 to 4 • 10–6 M/L at intravenous administration in rats does not have a significant effect on body mass dynamics and basic hematological parameters for 30 days. Thus, ZAIS QDs can be used to visualize tissues and organs in various pathological processes, and immobilization of the drugs on their surface will allow to approach their application for theranostics.
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9

Jung, Eun-Young, Jun-Hee Ye, Sung-Hee Jung, and Seong-Ho Choi. "Electrochemiluminescence Biosensor Based on Thioglycolic Acid-Capped CdSe QDs for Sensing Glucose." Journal of Nanomaterials 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/5760327.

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In order to detect low level glucose concentration, an electrochemiluminescence (ECL) biosensor based on TGA-capped CdSe quantum dots (QDs) was fabricated by the immobilization of CdSe QDs after modifying the surface of a glassy carbon electrode (GCE) with 4-aminothiophenol diazonium salts by the electrochemical method. For the detection of glucose concentration, glucose oxidase (GOD) was immobilized onto the fabricated CdSe QDs-modified electrode. The fabricated ECL biosensor based on TGA-capped CdSe QDs was characterized using a scanning electron microscope (SEM), UV-vis spectrophotometry, transmission electron microscopy (TEM), a fluorescence spectrometer (PL), and cyclic voltammetry (CV). The fabricated ECL biosensor based on TGA-capped CdSe QDs is suitable for the detection of glucose concentrations in real human blood samples.
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10

Tu, Li Ping, Xiang Yu, and Guo Wei Xu. "Performance of Photoelectrochemical Sensors Based on Doped QDs under Various Bias Voltage." Materials Science Forum 1001 (July 2020): 175–80. http://dx.doi.org/10.4028/www.scientific.net/msf.1001.175.

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In this paper, a novel photoelectrochemical sensor based on doped quantum dots (QDs) under various bias voltages was designed, first, photoelectrochemical sensors were designed for detection of chemical solution concentration. Second, the fabrication processes of doped QDs based sensors were described, third, doped QDs based sensors were tested under different applied potentials and light sources to show different measurement characteristics. From the experimental results, it can be concluded that the doped QDs based sensors designed under-300mV applied potential and 365nm light source show the best performance.
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11

Chen, Xian Lan, Wei Liu, Ju Cheng Zhang, Qing Shan Pan, Du Shu Huang, and Lin Xiang Dong. "Hydrothermal-Based Synthesis of CdS/ZnO Quantum Dots." Advanced Materials Research 875-877 (February 2014): 362–65. http://dx.doi.org/10.4028/www.scientific.net/amr.875-877.362.

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In this article, the CdS and CdS/ZnO quantum dots (QDs) were prepared by hydrothermal synthesis method. The optimal reaction conditions of CdS/ZnO QDs were obtained through experiment as follows: the pH value of solution is 10.0, the reaction temperature is 140 °C and reaction time is 24 h. While the pH value is up to10.0, Zinc ion exist in solution with Zn (OH)2 and Zn (OH)42-, which is apt to adsorb on the surface of CdS, and form to ZnO shell under the hydrothermal condition, so CdS/ZnO QDs are synthesized successfully. The photographic images and fluorescence emission spectra results showed that the colour and the peak position of fluorescence spectra of CdS/ZnO QDs is consistent with literatures, which confirming the feasibility of this method.
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12

Lesiak, Anna, Kamila Drzozga, Joanna Cabaj, Mateusz Bański, Karol Malecha, and Artur Podhorodecki. "Optical Sensors Based on II-VI Quantum Dots." Nanomaterials 9, no. 2 (February 2, 2019): 192. http://dx.doi.org/10.3390/nano9020192.

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Fundamentals of quantum dots (QDs) sensing phenomena show the predominance of these fluorophores over standard organic dyes, mainly because of their unique optical properties such as sharp and tunable emission spectra, high emission quantum yield and broad absorption. Moreover, they also indicate no photo bleaching and can be also grown as no blinking emitters. Due to these properties, QDs may be used e.g., for multiplex testing of the analyte by simultaneously detecting multiple or very weak signals. Physico-chemical mechanisms used for analyte detection, like analyte stimulated QDs aggregation, nonradiative Förster resonance energy transfer (FRET) exhibit a number of QDs, which can be applied in sensors. Quantum dots-based sensors find use in the detection of ions, organic compounds (e.g., proteins, sugars, volatile substances) as well as bacteria and viruses.
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13

Susumu, Kimihiro, H. Tetsuo Uyeda, Igor L. Medintz, and Hedi Mattoussi. "Design of Biotin-Functionalized Luminescent Quantum Dots." Journal of Biomedicine and Biotechnology 2007 (2007): 1–7. http://dx.doi.org/10.1155/2007/90651.

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We report the design and synthesis of a tetraethylene glycol- (TEG-) based bidentate ligand functionalized with dihydrolipoic acid (DHLA) and biotin (DHLA—TEG—biotin) to promote biocompatibility of luminescent quantum dots (QD's). This new ligand readily binds to CdSe—ZnS core-shell QDs via surface ligand exchange. QDs capped with a mixture of DHLA and DHLA—TEG—biotin or polyethylene glycol- (PEG-) (molecular weight average∼600) modified DHLA (DHLA—PEG600) and DHLA—TEG—biotin are easily dispersed in aqueous buffer solutions. In particular, homogeneous buffer solutions of QDs capped with a mixture of DHLA—PEG600 and DHLA—TEG—biotin that are stable over broad pH range have been prepared. QDs coated with mixtures of DHLA/DHLA—TEG—biotin and with DHLA—PEG600/DHLA—TEG—biotin were tested in surface binding assays and the results indicate that biotin groups on the QD surface interact specifically with NeutrAvidin-functionalized microtiter well plates.
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14

Hong, Wuding, Huijuan Kuang, Xingping He, Lin Yang, Pengfei Yang, Bolu Chen, Zoraida Aguilar, and Hengyi Xu. "CdSe/ZnS Quantum Dots Impaired the First Two Generations of Placenta Growth in an Animal Model, Based on the Shh Signaling Pathway." Nanomaterials 9, no. 2 (February 14, 2019): 257. http://dx.doi.org/10.3390/nano9020257.

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The toxicity, especially the transgenerational toxicity of quantum dots (QDs) in vivo, is still scarcely understood in spite of great promising applications of QDs in biomedicine. In this study, the maternal status, pregnancy outcome, and fetus development of parental generation (P0) to offspring in three generations (F3) were investigated after Kunming mice perinatal (GD 13-PND 5) exposure to Cd containing QDs (CdSe/ZnS QDs) and CdCl2. The results show CdSe/ZnS QDs induced placenta injuries in P0 and diminished placenta diameters in F1 and F2. Bodyweight growth decreased in the CdSe/ZnS QDs treatment group in the F1 and F2 generation. Additionally, CdSe/ZnS QDs significantly altered the expression of key genes in the Shh signal pathway. Overall, this study exhibited that the CdSe/ZnS QDs exposure during perinatal period impaired placenta growth in the first two generations, but not on the third generation. The toxicological actions of the CdSe/ZnS QDs might be through the effects on the Shh signal pathway.
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15

Lee, Jehoon, Hailiang Liu, and Jungwon Kang. "A Study on an Organic Semiconductor-Based Indirect X-ray Detector with Cd-Free QDs for Sensitivity Improvement." Sensors 20, no. 22 (November 17, 2020): 6562. http://dx.doi.org/10.3390/s20226562.

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In this paper, we studied the optimized conditions for adding inorganic quantum dots (QD) to the P3HT:PC70BM organic active layer to increase the sensitivity of the indirect X-ray detector. Commonly used QDs are composed of hazardous substances with environmental problems, so indium phosphide (InP) QDs were selected as the electron acceptor in this experiment. Among the three different sizes of InP QDs (4, 8, and 12 nm in diameter), the detector with 4 nm InP QDs showed the highest sensitivity, of 2.01 mA/Gy·cm2. To further improve the sensitivity, the QDs were fixed to 4 nm in diameter and then the amount of QDs added to the organic active layer was changed from 0 to 5 mg. The highest sensitivity, of 2.26 mA/Gy·cm2, was obtained from the detector with a P3HT:PC70BM:InP QDs (1 mg) active layer. In addition, the highest mobility, of 1.69 × 10−5 cm2/V·s, was obtained from the same detector. Compared to the detector with the pristine P3HT:PC70BM active layer, the detector with a P3HT:PC70BM:InP QDs (1 mg) active layer had sensitivity that was 61.87% higher. The cut-off frequency of the P3HT:PC70BM detector was 21.54 kHz, and that of the P3HT:PC70BM:InP QDs (1 mg) detector was 26.33 kHz, which was improved by 22.24%.
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16

Zhao, Fei, and Jongsung Kim. "Fabrication of a Dopamine Sensor Based on Carboxyl Quantum Dots." Journal of Nanoscience and Nanotechnology 15, no. 10 (October 1, 2015): 7871–75. http://dx.doi.org/10.1166/jnn.2015.11220.

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A quantum dot (QD)-based optical biosensor was developed to detect the activity of dopamine (DA) via the quenching of QD fluorescence intensity. In this study, we examined the fluorescence quenching of DA-conjugated quantum dots (DA@QDs) at various solution pH values. The fluorescence intensity of the QDs is quenched by electronic energy transfer from the QDs to the o-quinone group of dopamine oxide. The degree of fluorescence quenching was dependent on DA concentration. The influence of the external environment pH factor on fluorescence quenching was investigated. The results showed that the degree of fluorescence quenching of DA@QDs was highest in a slightly alkaline solution-pH of approximately 9. Fluorescence enhancement with increased pH appears to be due to electronic energy transfer, which is related to an increased degree of dopamine-o-quinone oxidation. The fluorescence quenching of QDs by DA is of considerable interest due to its potential for the direct detection of the DA in vivo via a simple procedure with a very low limit of detection.
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17

Wang, Yue, Danqun Huo, Huixiang Wu, Hui Liu, Junjie Li, Mei Yang, Chenghong Huang, and Changjun Hou. "A Ratiometric Fluorescent Assay for Fluazinam Based on FRET Between CdTe Quantum Dots and Porphyrin." Nano 12, no. 10 (October 2017): 1750128. http://dx.doi.org/10.1142/s1793292017501284.

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A fluorescent detection system for fluazinam was reported using fluorescence resonance energy transfer (FRET) method based on CdTe quantum dots (CdTe QDs) and 5, 10, 15, 20-tetrakis(4-methacryloyloxy) phenyl porphyrin (TMaPP). TMaPP and water-soluble CdTe QDs were synthesized successfully and characterized using FT-IR, 1H NMR, XPS and TEM, respectively. FRET mechanism between CdTe QDs and TMaPP was confirmed by detailed studies on their fluorescent spectra. After a co-culture of TMaPP and CdTe QDs, fluorescent intensity of CdTe QDs decreased significantly while that of TMaPP increased concomitantly due to altered FRET. Addition of fluazinam led to impaired energy transfer from CdTe QDs to TMaPP and therefore fluorescence recovery of CdTe QDs with fluorescence quenching of TMaPP. The correlation of fluazinam concentration with the fluorescence intensity ratio [Formula: see text] provided the basis for quantitative analysis, and a broad linear range varying from 0.01[Formula: see text][Formula: see text]M to 5[Formula: see text][Formula: see text]M with a low detection limit of 2.3[Formula: see text]nM was obtained. As-reported sensor system demonstrated excellent reproducibility, selectivity and sensitivity in real sample detection.
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18

Gao, Yanyan, Xiaoping Zou, Zhe Sun, Zongbo Huang, and Hongquan Zhou. "Enhancement of Electron Transfer Efficiency in Solar Cells Based on PbS QD/N719 Dye Cosensitizers." Journal of Nanomaterials 2012 (2012): 1–5. http://dx.doi.org/10.1155/2012/415370.

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Cosensitized solar cells (CSSCs) have recently become an active subject in the field of sensitized solar cells (SSCs) due to their increasing electronic utilization. However, because of the dye molecules, layer must be single, dye-SSCs cannot be co-sensitized with two different dyes to form two different molecules layer. But it is possible to be cosensitized with quantum dots (QDs) and dyes. Here we designed novel photoanode architecture, namely, PbS QDs and N719 dyes are used as co-sensitizers of the TiO2mesoporous film. The experimental result shows that PbS QDs/N719 dyes co-sensitized structure can make PbS QDs and N719 dyes mutual improvement. Taking the advantage of PbS not only achieved higher transfer efficiency of photo-excited electron, but also achieved obviously wider range and higher intensity of absorption. The PbS QDs which have been deposited on the TiO2film was coated by N719 dyes, which can effectively prevent PbS QDs from corroding byI-/I3-electrolyte and light. As we expected, the solar energy-conversion efficiency which is showed by CSSCs fabricated following these photoanodes is relatively higher than the PbS QDs or N719 dyes, single-sensitized solar cells under the illumination of one sun.
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19

Andreev, A. D., R. M. Datsiev, and R. P. Seisyan. "Absorption Spectra of ZnSe/CdSe-Based QDs." physica status solidi (b) 215, no. 1 (September 1999): 325–30. http://dx.doi.org/10.1002/(sici)1521-3951(199909)215:1<325::aid-pssb325>3.0.co;2-s.

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20

JACKERAY, RICHA, GURPAL SINGH, SWATI JAIN, ZAINUL ABID CKV, HARPAL SINGH, NEELAM H. ZAIDI, UDIT SONI, SAMEER SAPRA, and T. G. SHRIVASTAV. "BIOCONJUGATED QUANTUM DOTS BASED RAPID DETECTION OF PATHOGENIC BACTERIA FROM WATER SAMPLES." International Journal of Nanoscience 10, no. 01n02 (February 2011): 199–203. http://dx.doi.org/10.1142/s0219581x11007788.

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A sensitive and rapid method for the detection of pathogenic bacteria (Salmonella typhi) in water sample was developed using core-shell CdSe / ZnS quantum dots (QDs) as fluorescence label. Surface-functionalized core-shell quantum dots were synthesized by successive ion layer adsorption and reaction (SILAR) technique and were made hydrophilic by ligand exchange method. Developed hydrophobic and hydrophilic QDs were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and spectrofluorimetry. Carboxy- terminated QDs were conjugated with bacteria-specific antibodies (S. typhi-specific IgG) for the preparation of photostable fluorescent label and were characterized by various techniques like spectrofluorimetry and enzyme-linked immunosorbent assay (ELISA) for their photoluminescence and successful bioconjugation. Antibody (Ab)-conjugated QDs were incubated with bacteria-contaminated water for S. typhi detection. Microscopic images and spectral profile of bacteria–Ab conjugated QDs complex were recorded by confocal laser scanning microscopy (CLSM). A sensitivity of 103 organisms/mL of targeted bacteria (S. typhi) could be attained in a period of about 2 h.
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Ramkumar, Vanaraj, and Sanghyun Ju. "Quantum-Dot and Polychalcone Mixed Nanocomposites for Polymer Light-Emitting Diodes." Journal of Nanomaterials 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/8739193.

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The present work is aimed at improving the efficiency of light-emitting diodes (LEDs) through the amalgamation of polymeric materials and quantum dots (QDs) in nanocomposites. Herein, we report on the polytriphenylamine-based chalcone (PTpC) or polycarbazole-based chalcone- (PCzC-) QDs mixture nanocomposites as emissive layers for polymer LEDs (PLEDs). QDs were evenly dispersed in the polymer matrix and the synthesized PTpC-QDs and PCzC-QDs nanocomposites were able to form smooth thin films. The luminance characteristics of PTpC-QDs and PCzC-QDs nanocomposites were better than those of the pristine QD, PTpC, and PCzC materials, owing to the high charge-carrier transport ability of polymer-QDs nanocomposites. These results indicate that the proposed polymer-QDs nanocomposites could be potential candidates for application in PLEDs.
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Rezanejade Bardajee, Ghasem, and Zari Hooshyar. "CdTe Quantum Dots Embedded in Multidentate Biopolymer Based on Salep: Characterization and Optical Properties." Journal of Chemistry 2013 (2013): 1–6. http://dx.doi.org/10.1155/2013/202061.

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This paper describes a novel method for surface modification of water soluble CdTe quantum dots (QDs) by using poly(acrylic acid) grafted onto salep (salep-g-PAA) as a biopolymer. As-prepared CdTe-salep-g-PAA QDs were characterized by Fourier transform infrared (FT-IR) spectrum, thermogravimetric (TG) analysis, and transmission electron microscopy (TEM). The absorption and fluorescence emission spectra were measured to investigate the effect of salep-g-PAA biopolymer on the optical properties of CdTe QDs. The results showed that the optical properties of CdTe QDs were significantly enhanced by using salep-g-PAA-based biopolymer.
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Chen, Yanling, and Xue Bai. "A Review on Quantum Dots Modified g-C3N4-Based Photocatalysts with Improved Photocatalytic Activity." Catalysts 10, no. 1 (January 20, 2020): 142. http://dx.doi.org/10.3390/catal10010142.

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In the 21st century, the development of sustainable energy and advanced technologies to cope with energy shortages and environmental pollution has become vital. Semiconductor photocatalysis is a promising technology that can directly convert solar energy to chemical energy and is extensively used for its environmentally-friendly properties. In the field of photocatalysis, graphitic carbon nitride (g-C3N4) has obtained increasing interest due to its unique physicochemical properties. Therefore, numerous researchers have attempted to integrate quantum dots (QDs) with g-C3N4 to optimize the photocatalytic activity. In this review, recent progress in combining g-C3N4 with QDs for synthesizing new photocatalysts was introduced. The methods of QDs/g-C3N4-based photocatalysts synthesis are summarized. Recent studies assessing the application of photocatalytic performance and mechanism of modification of g-C3N4 with carbon quantum dots (CQDs), graphene quantum dots (GQDs), and g-C3N4 QDs are herein discussed. Lastly, challenges and future perspectives of QDs modified g-C3N4-based photocatalysts in photocatalytic applications are discussed. We hope that this review will provide a valuable overview and insight for the promotion of applications of QDs modified g-C3N4 based-photocatalysts.
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Mishra, Rajneesh Kumar, Gyu-Jin Choi, Hyeon-Jong Choi, and Jin-Seog Gwag. "ZnS Quantum Dot Based Acetone Sensor for Monitoring Health-Hazardous Gases in Indoor/Outdoor Environment." Micromachines 12, no. 6 (May 22, 2021): 598. http://dx.doi.org/10.3390/mi12060598.

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This study reports the ZnS quantum dots (QDs) synthesis by a hot-injection method for acetone gas sensing applications. The prepared ZnS QDs were characterized by X-ray diffraction (XRD) and transmission electron microscopy analysis. The XRD result confirms the successful formation of the wurtzite phase of ZnS, with a size of ~5 nm. Transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and fast Fourier transform (FFT) images reveal the synthesis of agglomerated ZnS QDs with different sizes, with lattice spacing (0.31 nm) corresponding to (111) lattice plane. The ZnS QDs sensor reveals a high sensitivity (92.4%) and fast response and recovery time (5.5 s and 6.7 s, respectively) for 100 ppm acetone at 175 °C. In addition, the ZnS QDs sensor elucidates high acetone selectivity of 91.1% as compared with other intrusive gases such as ammonia (16.0%), toluene (21.1%), ethanol (26.3%), butanol (11.2%), formaldehyde (9.6%), isopropanol (22.3%), and benzene (18.7%) for 100 ppm acetone concentration at 175 °C. Furthermore, it depicts outstanding stability (89.1%) during thirty days, with five day intervals, for 100 ppm at an operating temperature of 175 °C. In addition, the ZnS QDs acetone sensor elucidates a theoretical detection limit of ~1.2 ppm at 175 °C. Therefore, ZnS QDs can be a promising and quick traceable sensor nanomaterial for acetone sensing applications.
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Liu, Wenyan, Yu Zhang, Cheng Ruan, Dan Wang, Tieqiang Zhang, Yi Feng, Wenzhu Gao, et al. "ZnCuInS/ZnSe/ZnS Quantum Dot-Based Downconversion Light-Emitting Diodes and Their Thermal Effect." Journal of Nanomaterials 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/298614.

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The quantum dot-based light-emitting diodes (QD-LEDs) were fabricated using blue GaN chips and red-, yellow-, and green-emitting ZnCuInS/ZnSe/ZnS QDs. The power efficiencies were measured as 14.0 lm/W for red, 47.1 lm/W for yellow, and 62.4 lm/W for green LEDs at 2.6 V. The temperature effect of ZnCuInS/ZnSe/ZnS QDs on these LEDs was investigated using CIE chromaticity coordinates, spectral wavelength, full width at half maximum (FWHM), and power efficiency (PE). The thermal quenching induced by the increased surface temperature of the device was confirmed to be one of the important factors to decrease power efficiencies while the CIE chromaticity coordinates changed little due to the low emission temperature coefficients of 0.022, 0.050, and 0.068 nm/°C for red-, yellow-, and green-emitting ZnCuInS/ZnSe/ZnS QDs. These indicate that ZnCuInS/ZnSe/ZnS QDs are more suitable for downconversion LEDs compared to CdSe QDs.
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Wang, Jigang, Yong Sheng Wang, Da Wei He, Shu Lei Li, Jia Qi He, Hong Peng Wu, Hai Teng Wang, et al. "Research Based on Dependencies of Luminescent Properties of CdTe Quantum Dots with TGA as Surfactant." Advanced Materials Research 740 (August 2013): 715–20. http://dx.doi.org/10.4028/www.scientific.net/amr.740.715.

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We investigated the optical characterization of luminescent thioglycolic acid (TGA) stabilized CdTe quantum dots (CdTe-QD) synthesized in water. The influence of stabilizing agents on the luminescent properties of water-soluble CdTe quantum dots (QDs) was described. It is found that QDs can be synthesized easily when TGA is chosen as stabilizing agent and TGA leads to preparation of highly luminescent QDs due to the secondary effects of bonds between Cd2+ and sulfhydryl groups. The absorption wavelength and PL stability of TGA-CdTe are also characterized. Size can be controlled between 2.0 nm to 4.0 nm. The TGA-CdTe QDs prepared at 2 h reaction time possess excellent luminescent properties.
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Hartwig, Melinda, Franz Ortlepp, Martin Möbius, Jörg Martin, Thomas Otto, Thomas Geßner, and Reinhard R. Baumann. "Inkjet-printed quantum dot-based sensor for structural health monitoring." MRS Proceedings 1788 (2015): 57–62. http://dx.doi.org/10.1557/opl.2015.855.

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ABSTRACTA sensor which detects mechanical stresses and stores the position and the strength of these loads by color change of embedded quantum dots (QDs) is presented. The top and bottom electrodes of the sensor are inkjet-printed which leads to a fast and accurate deposition of thin (approx. 50 - 300 nm) and conductive layers. The used silver and poly(3,4-ethylenedioxythio-phene) polystyrene sulfonate (PEDOT:PSS) inks are optimized in terms of printability and opportunities of functionality forming without influencing the active layer of the sensor. The active layer of the sensor is spin-coated and consists of the QDs embedded in semi-conducting poly(9-vinylcarba-zole) (PVK). The hole transport characteristic of PVK and the band level alignment of the used materials ensures the preferred injection of only one type of charge carrier into the QDs. As a result the mechanical stress is visualized by a decreasing in photoluminescence (PL) of the QDs.
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Lv, Jinzhi, Yanming Miao, and Guiqin Yan. "Detection of specific DNA sequences in Maize (Zea mays L.) based on phosphorescent quantum-dot exciton energy transfer." New Journal of Chemistry 43, no. 14 (2019): 5308–14. http://dx.doi.org/10.1039/c8nj06106h.

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The complementary sequence of genetically-modified marker sequence cauliflower mosaic virus 35S promoter (Ca MV 35S) DNA was trimmed and designed into sequences S1 and S2, which were separately modified onto the surfaces of room-temperature phosphorescent (RTP) quantum dots (QDs), forming QDs-S1 (P1) and QDs-S2 (P2), respectively.
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Hu, Bo, Yang Lu, Keyu Cui, and Yongsheng Yan. "Molecular Imprinting Polymers Based on Boric Acid-Modified CdTe QDs for Sensitive Detection of Glucose." Nano 13, no. 04 (April 2018): 1850046. http://dx.doi.org/10.1142/s1793292018500467.

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In this study, a novel imprinted polymer based on 3-aminophenylboronic acid (APBA)-functionalized CdTe quantum dots (QDs) was synthesized and used to sensitively and selectively detect glucose. In the process of synthesis, the boronic acid in the APBA could combine covalently with vicinal diol compounds, directing imprinting process, and the APBA-modified CdTe QDs were used as the solid supports. By this method, the prepared molecular imprinting polymers (MIPs)-APBA/CdTe QDs show high selectivity, high sensitivity and good stability. Under optimal conditions, a linear relationship was obtained covering the linear range of 0–1.5[Formula: see text]mmol/L with a correlation coefficient of 0.99833 and a high imprinting factor about 5.71. Furthermore, the prepared MIPs-APBA/CdTe QDs were successfully applied to detect glucose in human serum samples. This work provides a new way to synthesize an excellent stability and efficient imprinted polymer based on CdTe QDs for convenient, fast and highly selective detection of glucose.
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Jiang, Lu, Su, Feng, Zhou, Hong, Sun, and Li. "High Sensitivity Detection of Copper Ions in Oysters Based on the Fluorescence Property of Cadmium Selenide Quantum Dots." Chemosensors 7, no. 4 (September 25, 2019): 47. http://dx.doi.org/10.3390/chemosensors7040047.

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Cadmium selenide (CdSe) quantum dots (QDs) were synthesized by water phase synthesis method using 3-mercaptopropionic acid (3-MPA) as a stabilizer, and they were applied to the detection of copper ions (Cu2+). The results showed that CdSe QDs have excellent selectivity and sensitivity toward Cu2+. The fluorescence intensity of CdSe QDs decreased with the increase of Cu2+ concentration. The linear range was from 30 nM to 3 μM, and the detection limit was 30 nM. Furthermore, CdSe QDs were used for detecting the concentration of Cu2+ in oysters. The content of Cu2+ was 40.91 mg/kg, which was close to the one measured via flame atomic absorption spectrometry (FAAS), and the relative error was 1.81%. Therefore, CdSe QDs have a wide application prospect in the rapid detection of copper ions in food.
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Mokwebo, Kefilwe, Oluwatobi Oluwafemi, and Omotayo Arotiba. "An Electrochemical Cholesterol Biosensor Based on A CdTe/CdSe/ZnSe Quantum Dots—Poly (Propylene Imine) Dendrimer Nanocomposite Immobilisation Layer." Sensors 18, no. 10 (October 9, 2018): 3368. http://dx.doi.org/10.3390/s18103368.

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We report the preparation of poly (propylene imine) dendrimer (PPI) and CdTe/CdSe/ZnSe quantum dots (QDs) as a suitable platform for the development of an enzyme-based electrochemical cholesterol biosensor with enhanced analytical performance. The mercaptopropionic acid (MPA)-capped CdTe/CdSe/ZnSe QDs was synthesized in an aqueous phase and characterized using photoluminescence (PL) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, transmission electron microscopy (TEM), X-ray power diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy. The absorption and emission maxima of the QDs red shifted as the reaction time and shell growth increased, indicating the formation of CdTe/CdSe/ZnSe QDs. PPI was electrodeposited on a glassy carbon electrode followed by the deposition (by deep coating) attachment of the QDs onto the PPI dendrimer modified electrode using 1-Ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC), and N-hydroxysuccinimide (NHS) as a coupling agent. The biosensor was prepared by incubating the PPI/QDs modified electrode into a solution of cholesterol oxidase (ChOx) for 6 h. The modified electrodes were characterized by voltammetry and impedance spectroscopy. Since efficient electron transfer process between the enzyme cholesterol oxidase (ChOx) and the PPI/QDs-modified electrode was achieved, the cholesterol biosensor (GCE/PPI/QDs/ChOx) was able to detect cholesterol in the range 0.1–10 mM with a detection limit (LOD) of 0.075 mM and sensitivity of 111.16 μA mM−1 cm−2. The biosensor was stable for over a month and had greater selectivity towards the cholesterol molecule.
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Kuznetsova, Vera, Viktoria Osipova, Anton Tkach, Maksim Miropoltsev, Danil Kurshanov, Anastasiia Sokolova, Sergei Cherevkov, et al. "Lab-on-Microsphere—FRET-Based Multiplex Sensor Platform." Nanomaterials 11, no. 1 (January 5, 2021): 109. http://dx.doi.org/10.3390/nano11010109.

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Here we report on the development and investigation of a novel multiplex assay model based on polymer microspheres (PMS) encoded with ternary AIS/ZnS quantum dots (QDs). The system was prepared via layer-by-layer deposition technique. Our studies of Förster resonance energy transfer (FRET) between the QD-encoded microspheres and two different cyanine dyes have demonstrated that the QD photoluminescence (PL) quenching steadily increases with a decrease in the QD-dye distance. We have found that the sensitized dye PL intensity demonstrates a clear maximum at two double layers of polyelectrolytes between QDs and Dye molecules on the polymer microspheres. Time resolved PL measurements have shown that the PL lifetime decreases for the QDs and increases for the dyes due to FRET. The designed system makes it possible to record spectrally different bands of FRET-induced dye luminescence with different decay times and thereby allows for the multiplexing by wavelength and photoluminescence lifetimes of the dyes. We believe that PMS encoded with AIS/ZnS QDs have great potential for the development of new highly selective and sensitive sensor systems for multiplex analysis to detect cell lysates and body fluids’ representative biomarkers.
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Zhang, Zhang, and Liu. "Luminescent Molecularly Imprinted Polymers Based on Covalent Organic Frameworks and Quantum Dots with Strong Optical Response to Quinoxaline-2-Carboxylicacid." Polymers 11, no. 4 (April 17, 2019): 708. http://dx.doi.org/10.3390/polym11040708.

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Three-dimensional molecularly imprinted polymers (MIPs) based on quantum dots-grafted covalent organic frameworks (QDs-grafted COFs) are reported in this study. The compound 1,3,5-triformylphloroglucinol-P-phenylenediamine was used as COF material to react with the amino-modified CdSe/ZnS QDs by Schiff-base reactions. The amino-derived QDs reacted with quinoxaline-2-carboxylicacid (QCA) via a non-covalent interaction. The system combines the advantages of MIPs, COFs, and QDs for highly sensitive and selective QCA detection. The MIPs based on QDs-grafted COFs showed good chemical selectivity and thermal stability, as well as consistency in QCA optosensing. Under optimal conditions, the detection limit for QCA in meat and feed samples was 0.85 μmol L−1, over a linear concentration range of 1–50 μmol L−1. The current findings suggest a potential application of MIPs based on QDs-grafted COFs for the detection of trace levels of hazardous chemicals for food safety and environmental control.
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Sajjad, Muhammad T., Ashu K. Bansal, Francesco Antolini, Eduard Preis, Lenuta Stroea, Stefano Toffanin, Michele Muccini, et al. "Development of Quantum Dot (QD) Based Color Converters for Multicolor Display." Nanomaterials 11, no. 5 (April 23, 2021): 1089. http://dx.doi.org/10.3390/nano11051089.

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Many displays involve the use of color conversion layers. QDs are attractive candidates as color converters because of their easy processability, tuneable optical properties, high photoluminescence quantum yield, and good stability. Here, we show that emissive QDs with narrow emission range can be made in-situ in a polymer matrix, with properties useful for color conversion. This was achieved by blending the blue-emitting pyridine based polymer with a cadmium selenide precursor and baking their films at different temperatures. To achieve efficient color conversion, blend ratio and baking temperature/time were varied. We found that thermal decomposition of the precursor leads to highly emissive QDs whose final size and emission can be controlled using baking temperature/time. The formation of the QDs inside the polymer matrix was confirmed through morphological studies using atomic force microscopy (AFM) and transmission electron microscopy (TEM). Hence, our approach provides a cost-effective route to making highly emissive color converters for multi-color displays.
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Zhang, Jinyuan, and Huaimin Gu. "Growth of InZnP/ZnS core/shell quantum dots with wide-range and refined tunable photoluminescence wavelengths." Dalton Transactions 49, no. 18 (2020): 6119–26. http://dx.doi.org/10.1039/d0dt00575d.

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InP-based QDs show great potential in various fields as an alternative to Cd-based QDs, through the feasible regulation of Zn, In, P and S precursors, the PL wavelength of InP-based QDs can be widely and accurately tuned from 484 nm to 651 nm.
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36

Li, Dongxia, Junping Guo, Liang Zhao, Guoxian Zhang, and Guiqin Yan. "A label-free RTP sensor based on aptamer/quantum dot nanocomposites for cytochrome c detection." RSC Advances 9, no. 55 (2019): 31953–59. http://dx.doi.org/10.1039/c9ra05761g.

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37

Zheng, Yaxin, Bahareh Sadeghimakki, Navid M. S. Jahed, and Siva Sivoththaman. "Scalable Non-injection Synthesis of Cd-Free Copper Indium Sulfide/Zinc Sulfide Quantum Dots for Third-Gen Photovoltaic Application." MRS Advances 1, no. 30 (2016): 2193–98. http://dx.doi.org/10.1557/adv.2016.536.

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ABSTRACTCopper Indium Sulfide (CIS)-based quantum dots (QDs) are considered as a safer alternative compared to carcinogenic cadmium- and lead-based QDs. Here, we present a facile, high throughput, and non-injection method of synthesizing CIS-based QDs. The structure, shape, size, and crystalline structure of the synthesized QDs were studied using high resolution transmission electron microscopy (HRTEM). The effects of temperature and compositional dependency on the structure and optical properties of the resulting QDs were investigated using elemental, absorption, photoluminescence (PL), and time-resolved spectroscopic analyses. We observed that a gradient increase of temperature during the core growth, as well as addition of excess indium (In) and zinc (Zn) precursors during core and core/shell synthesis, at low growth temperatures, resulted in QDs with improved PL and lifetime. The large Stokes shift, broad emission spectra, and long-lived emission of the synthesized QDs reveal their potential applicability to third generation photovoltaic and optoelectronic devices.
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Li, Xiu-Ping, Rong-Jin Huang, Cong Chen, Tianduo Li, and Yu-Ji Gao. "Simultaneous Conduction and Valence Band Regulation of Indium-Based Quantum Dots for Efficient H2 Photogeneration." Nanomaterials 11, no. 5 (April 26, 2021): 1115. http://dx.doi.org/10.3390/nano11051115.

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Indium-based chalcogenide semiconductors have been served as the promising candidates for solar H2 evolution reaction, however, the related studies are still in its infancy and the enhancement of efficiency remains a grand challenge. Here, we report that the photocatalytic H2 evolution activity of quantized indium chalcogenide semiconductors could be dramatically aroused by the co-decoration of transition metal Zn and Cu. Different from the traditional metal ion doping strategies which only focus on narrowing bandgap for robust visible light harvesting, the conduction and valence band are coordinately regulated to realize the bandgap narrowing and the raising of thermodynamic driving force for proton reduction, simultaneously. Therefore, the as-prepared noble metal-free Cu0.4-ZnIn2S4 quantum dots (QDs) exhibits extraordinary activity for photocatalytic H2 evolution. Under optimal conditions, the Cu0.4-ZnIn2S4 QDs could produce H2 with the rate of 144.4 μmol h−1 mg−1, 480-fold and 6-fold higher than that of pristine In2S3 QDs and Cu-doped In2S3 QDs counterparts respectively, which is even comparable with the state-of-the-art cadmium chalcogenides QDs.
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Jose Varghese, Rajendran, and Oluwatobi Samuel Oluwafemi. "The Photoluminescence and Biocompatibility of CuInS2-Based Ternary Quantum Dots and Their Biological Applications." Chemosensors 8, no. 4 (October 15, 2020): 101. http://dx.doi.org/10.3390/chemosensors8040101.

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Semiconductor quantum dots (QDs) have become a unique class of materials with great potential for applications in biomedical and optoelectronic devices. However, conventional QDs contains toxic heavy metals such as Pb, Cd and Hg. Hence, it is imperative to find an alternative material with similar optical properties and low cytotoxicity. Among these materials, CuInS2 (CIS) QDs have attracted a lot of interest due to their direct band gap in the infrared region, large optical absorption coefficient and low toxic composition. These factors make them a good material for biomedical application. This review starts with the origin and photophysical characteristics of CIS QDs. This is followed by various synthetic strategies, including synthesis in organic and aqueous solvents, and the tuning of their optical properties. Lastly, their significance in various biological applications is presented with their prospects in clinical applications.
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An, Jaehyun, Kim-Hung Huynh, Yuna Ha, Heung Su Jung, Hyung-Mo Kim, Dong-Min Kim, Jaehi Kim, et al. "Surface Modification of a Stable CdSeZnS/ZnS Alloy Quantum Dot for Immunoassay." Journal of Nanomaterials 2020 (October 16, 2020): 1–9. http://dx.doi.org/10.1155/2020/4937049.

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Quantum dots (QDs) are powerful materials in various bioapplications based on their excellent optical and electronic properties. For the application of various fields of QDs, surface modification of QDs is necessary. However, surface modification in QDs may result in a reduction in quantum yield (QY). This reduction of QY causes many weaknesses in the biological application of QDs. In this study, CdSeZnS/ZnS alloy QDs were used to prepare antibody-conjugated QDs for a sandwich immunoassay. The alloy QDs displayed a QY of 84.5% that was maintained at 83.0% (98.2% of QY was maintained) after surface modification with the anti-rabbit IgG as a model study. Surface-modified QDs successfully detected their corresponding target through antibody-antigen binding. The limit of detection was 1.1 × 10 2 ng mL-1 for rabbit IgG.
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41

Volkova, N. S., A. P. Gorshkov, L. A. Istomin, A. V. Zdoroveyshchev, and S. Levichev. "Diagnostic of the Bimodal Distribution of InAs/GaAs Quantum Dots by Means of a Simple Nondestructive Method Based on the Photoelectrical Spectroscopy." Nano 11, no. 10 (September 29, 2016): 1650109. http://dx.doi.org/10.1142/s1793292016501095.

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Photoelectric spectra of heterostructures containing InAs quantum dots (QDs) produced in different technological regimes were studied. A simple nondestructive method to reveal a bimodality of the QDs’ size distribution was described. The method based on the analysis of the shape of InAs/GaAs QDs’ photoelectric spectra and their temperature dependencies. The quantitative analysis of the temperature dependencies of the photoelectrical spectra was performed. All possible emission processes occurring from quantum confined levels to the semiconductor matrix were considered at the simulation. The surface concentration of the QDs was estimated.
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42

Permatasari, Fitri Aulia, Muhammad Alief Irham, Satria Zulkarnaen Bisri, and Ferry Iskandar. "Carbon-Based Quantum Dots for Supercapacitors: Recent Advances and Future Challenges." Nanomaterials 11, no. 1 (January 3, 2021): 91. http://dx.doi.org/10.3390/nano11010091.

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Carbon-based Quantum dots (C-QDs) are carbon-based materials that experience the quantum confinement effect, which results in superior optoelectronic properties. In recent years, C-QDs have attracted attention significantly and have shown great application potential as a high-performance supercapacitor device. C-QDs (either as a bare electrode or composite) give a new way to boost supercapacitor performances in higher specific capacitance, high energy density, and good durability. This review comprehensively summarizes the up-to-date progress in C-QD applications either in a bare condition or as a composite with other materials for supercapacitors. The current state of the three distinct C-QD families used for supercapacitors including carbon quantum dots, carbon dots, and graphene quantum dots is highlighted. Two main properties of C-QDs (structural and electrical properties) are presented and analyzed, with a focus on the contribution to supercapacitor performances. Finally, we discuss and outline the remaining major challenges and future perspectives for this growing field with the hope of stimulating further research progress.
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Lai, Qizhen, Yucheng Liu, Lan Ge, Yeling Yang, Xinghu Ji, and Zhike He. "Investigating the effect of 6-mercaptohexanol on the performance of a biosensor based on nanosurface energy transfer between gold nanoparticles and quantum dots." Analytical Methods 13, no. 18 (2021): 2092–98. http://dx.doi.org/10.1039/d1ay00209k.

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The MCH treatment of DNA-AuNPs allowed the free DNA-QDs to be more distant from the surface of DNA-AuNPs, weakening their NSET quenching effect on free DNA-QDs in the presence of a target, which endows MCH/DNA-Au-QDs with a higher signal to background ratio.
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44

Campbell, Sawyer D., and Richard W. Ziolkowski. "The Performance of Active Coated Nanoparticles Based on Quantum-Dot Gain Media." Advances in OptoElectronics 2012 (September 20, 2012): 1–6. http://dx.doi.org/10.1155/2012/368786.

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Quantum-dots (QDs) provide an exciting option for the gain media incorporated in active coated nanoparticles (CNPs) because they possess large gain coefficients resulting from their extreme confinement effects. The optical properties of core/shell QDs can be tuned by changing the relative size of the core/shell, that is, by effectively changing its band gap structure. Similarly, the resonance of a CNP can be adjusted by changing the relative sizes of its layers. It is demonstrated here that by optimally locating the QDs inside a resonant CNP structure it is possible to greatly enhance the intrinsic amplifying behavior of the combined QD-CNP system.
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Li, Jingshuai, Bin Du, Yuewen Li, Yaoguang Wang, Dan Wu, and Qin Wei. "A turn-on fluorescent sensor for highly sensitive mercury(ii) detection based on a carbon dot-labeled oligodeoxyribonucleotide and MnO2 nanosheets." New Journal of Chemistry 42, no. 2 (2018): 1228–34. http://dx.doi.org/10.1039/c7nj04120a.

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Ma, Qiang, and Xingguang Su. "Recent advances and applications in QDs-based sensors." Analyst 136, no. 23 (2011): 4883. http://dx.doi.org/10.1039/c1an15741h.

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47

LI, JUNWEI, YANG JIANG, YUGANG ZHANG, DI WU, ANQI LUO, and ZHONGPING ZHANG. "AQUEOUS SYNTHESIS OF HIGH QUANTUM YIELD AND MONODISPERSED THIOL-CAPPED CdxZn1-xTe QUANTUM DOTS BASED ON ELECTROCHEMICAL METHOD." Nano 07, no. 02 (April 2012): 1250011. http://dx.doi.org/10.1142/s1793292012500117.

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A facile green approach has been developed to control the growth regime in the aqueous synthesis of CdxZn1-xTe semiconductor quantum dots (QDs) based on the electrochemistry method. The Low growth temperature and slow injection of Te precursor are used to prolong the diffusion controlled stage and thus suppress Ostwald ripening during the nanocrystal growth. The experimental results showed that a low concentration of Te precursor will definitely influence the growth procedure. The UV–visible absorption spectra, as well as transmission electron microscopy (TEM) shows the QDs a good monodispersity at any interval of the reaction procedure. The high-resolution transmission electron microscopy (HRTEM) images and powder X-ray diffraction (XRD) pattern suggested that the as-prepared QDs have high crystallinity and cubic structure. The size and composition-dependent fluorescent emission wavelength of the resultant CdxZn1-xTe alloyed QDs can be tuned from 460 to 610 nm, and their photoluminescent quantum yield can reach up to 70%. Especially in the wavelength range of 510–578 nm, the overall PL QYs of the as-prepared CdxZn1-xTe QDs were above 50%. The current work suggests that electrochemical method is an attractive approach to the synthesis of high-quality II-VI ternary alloyed semiconductor QDs at large-scale with a prominent cost advantage.
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Qi, Hui, Shujie Wang, Xiaohong Jiang, Yan Fang, Aqiang Wang, Huaibin Shen, and Zuliang Du. "Research progress and challenges of blue light-emitting diodes based on II–VI semiconductor quantum dots." Journal of Materials Chemistry C 8, no. 30 (2020): 10160–73. http://dx.doi.org/10.1039/d0tc02272a.

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The latest progress of blue light-emitting diodes based on II–VI semiconductor QDs was reviewed, covering the synthesis of blue QDs, device structures, carrier transport materials, interface regulation, and light outcoupling technology.
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Pan, Tao, Shao Ying Ke, Zhang Sheng Shi, Chong Wang, and Yu Yang. "Strain Distribution of Ge/Si Quantum Dots in Array." Materials Science Forum 852 (April 2016): 229–37. http://dx.doi.org/10.4028/www.scientific.net/msf.852.229.

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Strain has valuable effects on the formation of the growth and the photo electronic properties of Ge/Si quantum dots (QDs), and it is important to understand the distribution of strain and the other properties of Ge/Si QDs theoretically. In this work, a method based on the Green’s function technique is used to solve elastic equations and the strain of different QDs shapes is calculated by a numerical algorithm. The strain of QDs which array in different density is analyzed and the strain of hemispherical QDs is compared with pyramidal QDs in calculations.
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Kuznetsova, Vera, Anton Tkach, Sergei Cherevkov, Anastasiia Sokolova, Yulia Gromova, Viktoria Osipova, Mikhail Baranov, Valery Ugolkov, Anatoly Fedorov, and Alexander Baranov. "Spectral-Time Multiplexing in FRET Complexes of AgInS2/ZnS Quantum Dot and Organic Dyes." Nanomaterials 10, no. 8 (August 10, 2020): 1569. http://dx.doi.org/10.3390/nano10081569.

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Nowadays, multiplex analysis is very popular, since it allows to detect a large number of biomarkers simultaneously. Traditional multiplex analysis is usually based on changes of photoluminescence (PL) intensity and/or PL band spectral positions in the presence of analytes. Using PL lifetime as an additional parameter might increase the efficiency of multiplex methods. Quantum dots (QDs) can be used as luminescent markers for multiplex analysis. Ternary in-based QDs are a great alternative to the traditional Cd-based one. Ternary QDs possess all advantages of traditional QDs, including tunable photoluminescence in visible range. At the same time ternary QDs do not have Cd-toxicity, and moreover they possess long spectral dependent lifetimes. This allows the use of ternary QDs as a donor for time-resolved multiplex sensing based on Förster resonance energy transfer (FRET). In the present work, we implemented FRET from AgInS2/ZnS ternary QDs to cyanine dyes absorbing in different spectral regions of QD luminescence with different lifetimes. As the result, FRET-induced luminescence of dyes differed not only in wavelengths but also in lifetimes of luminescence, which can be used for time-resolved multiplex analysis in biology and medicine.
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