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Journal articles on the topic 'Exciton absorption band'

Author: Grafiati

Published: 28 May 2022

Last updated: 31 July 2025

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1

Heckotter, J., M. Freitag, M. Abmann, et al. "Critical dependence of the excitonic absorption in cuprous oxide on experimental parameters." Физика твердого тела 60, no. 8 (2018): 1584. http://dx.doi.org/10.21883/ftt.2018.08.46251.19gr.

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AbstractWe study the modification of the exciton absorption in cuprous oxide by the presence of free carriers excited through above band gap excitation. Without this pumping, the absorption spectrum below the band gap consists of the yellow exciton series with principal quantum numbers up to more than n = 20, depending on the temperature, changing over to an about constant, only slowly varying absorption above the gap. Careful injection of free carriers, starting from densities well below 1 μm^–3, leads to a reduction of the band gap through correlation effects. The excitons in the Rydberg reg

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2

ITOH, T., K. YAMANAKA, K. EDAMATSU, T. UOZUMI, and Y. KAYANUMA. "PHOTOPHYSICS OF CONFINED EXCITONS IN CuCl NANOPARTICLES - CONFINEMENT OF EXCITON EXCITED STATES -." International Journal of Modern Physics B 15, no. 28n30 (2001): 3569–73. http://dx.doi.org/10.1142/s0217979201008172.

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Exciton excited states of CuCl nanoparticles dispersed in NaCl matrix have been investigated by means of two-photon excitation and two-step IR transient absorption. In the two-photon excitation spectra, there appears a distinct absorption edge. As the particle radius decreases from 6.3nm to 1.6nm, the edge energy increases by about 0.15eV, more than twice as large as that of the lowest 1S state. The fast decay component of the IR transient absorption under pulsed excitation of the lowest 1S exciton shows a broad band which shifts from 0.2 to 0.4eV as the radius decreases from >10nm to 1.4nm

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3

Cheng, Zhiqiang, Xiaoyou Niu, Shenlong Jiang, and Qun Zhang. "State-selective exciton–plasmon interplay in a hybrid WSe₂/CuFeS₂ nanosystem." Journal of Chemical Physics 156, no. 14 (2022): 144701. http://dx.doi.org/10.1063/5.0090467.

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The integration of confined exciton and localized surface plasmon in a hybrid nanostructure has recently stimulated extensive interests. The mechanistic insights into the elusive exciton–plasmon interplay at the nanoscale are of both fundamental and applicable values. Herein, by taking a hybrid WSe2/CuFeS2 system as a prototype, in which the excitonic semiconductor WSe2 nanosheets are interfaced with the plasmonic semiconductor CuFeS2 nanocrystals to form a heterostructure, we design and perform an ultrafast dynamics study to glean information in this regard. Specifically, the band-alignment r

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4

KAJITA, MASAKAZU, MAKOTO SHIMIZU, ARUP NEOGI, and TERUYA ISHIHARA. "ULTRAFAST PHOTO-INDUCED ABSORPTION CHANGE IN INORGANIC-ORGANIC MUTIPLE QUANTUM WELL COMPOUND." International Journal of Modern Physics B 15, no. 28n30 (2001): 3741–44. http://dx.doi.org/10.1142/s021797920100855x.

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We have performed pump-and-probe measurements to investigate ultrafast excitonic non-linearity expected in an inorganic-organic compound (C6H5C2H4NH3)2PbI4 , which has huge exciton binding energy (220 meV) and oscillator strength (0.5 per formula unit) by virture of the small dielectric constant in the barrier layer (the dielectric confinement or image charge effect). When the pump photon energy is set at the exciton level at 2.37 eV or above the band gap, the absorption decreases immediately after the pump due to the phase space filling effect and retrieves in a few ps. The retrieval time is

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5

Kovalenko, E. N., O. N. Yunakova, and N. N. Yunakov. "Exciton absorption spectrum of K2CuCl3 thin films." Low Temperature Physics 51, no. 4 (2025): 506–8. https://doi.org/10.1063/10.0036246.

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The absorption spectrum of a thin K2CuCl3 film was studied in the spectral region of 2–6 eV and the temperature range of 90–333 K. The analysis of the spectrum revealed the cationic nature of excitons in the K2CuCl3 compound. The exciton spectrum of K2CuCl3 is interpreted based on transitions in the Cu+ ion. The one-dimensional character of excitons in K2CuCl3 is determined from the temperature dependence of the broadening of the Г(T) intense long-wave exciton band A.

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6

GÖPPERT, M., R. BECKER, C. MAIER, M. JÖRGER, A. JOLK, and C. KLINGSHIRN. "INFRARED ABSORPTION BY EXCITONS IN CUPROUS OXIDE." International Journal of Modern Physics B 15, no. 28n30 (2001): 3615–18. http://dx.doi.org/10.1142/s0217979201008275.

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We report on the first observation of the 1s to 2p exciton transition in a direct gap semiconductor. Cuprous oxide is well known for its excitonic features which provide a model case for the theory of Wannier excitons. In our pump-probe experiment we measured the infrared transmission of cuprous oxide with the without Ar +-laser illumination. The observed photo-induced absorption line in the differential transmission spectra at 126 meV is assigned to the excitonic transition from 1s to 2p exciton levels i.e. to the analog of the Lyman series in atomic hydrogen. From the dependence of the integ

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7

Ran, Xing, Xin Xiang, Feng Zhou, and Shunbin Lu. "Exciton-Resonance-Enhanced Two-Photon Absorption in Three-Dimensional Hybrid Organic–Inorganic Perovskites." Photonics 12, no. 3 (2025): 261. https://doi.org/10.3390/photonics12030261.

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Three-dimensional (3D) hybrid organic–inorganic perovskites (HOIPs) have attracted tremendous interest due to strong excitonic effects and large optical nonlinearities. Taking the advantages, 3D HOIPs show great potential for applications in excitonic and nonlinear devices. However, understanding the relevant mechanisms of exciton-associated nonlinear optical phenomena in 3D perovskites is still challenging. Here, we apply the quantum perturbation theory to calculate the exciton-associated degenerate 2PA spectra of 3D HOIPs. The calculated 2PA spectra of twelve 3D HOIPs are predicted to exhibi

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8

Ratner, A. M. "Anomalous multiphonon scattering of intermediate radius excitons." Soviet Journal of Low Temperature Physics 11, no. 4 (1985): 222–27. https://doi.org/10.1063/10.0031276.

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In contrast to previous works which studied the effects of single-phonon scattering, we have studied multiphonon scattering of broadband excitons, related to the transformation of them into local excitations. The integrated cross section for such scattering as a function of exciton energy reproduces the absorption band of the local center and becomes anomalously strong in the central region of the band where a peak appears in the exciton dispersion curve.

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9

Maşnic, Alisa. "BIREFRINGENCE AND EXCITON SPECTRA OF CuAlSe2 AND CuAlS2 CRYSTALS." Journal of Engineering Science XXVII (1) (March 15, 2020): 23–27. https://doi.org/10.5281/zenodo.3713358.

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The excitonic reflection spectra of CuAlS<sub>2</sub> and CuAlSe<sub>2</sub> crystals were measured at the temperature of 10 K for polarizations<em> E||c </em>and <em>E</em><em>&perp;c</em>. Ground and excited states of the excitons were found out in the investigated spectra. Symmetries of the observed excitons were determined.  The shapes of ground states lines of<em> </em><em>Г<sub>4 </sub></em>and<em> </em><em>Г<sub>5 </sub></em>excitons were calculated by means of the Kramers-Kronig relations. Exciton parameters and values of energetic gaps (Г<sub>7</sub>-Г<sub>6</sub>, Г<sub>6</sub>-

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10

Golineĩ, I. Yu, and V. I. Sugakov. "Optical properties of metals with helium crystallized in their pores." Soviet Journal of Low Temperature Physics 11, no. 7 (1985): 427–28. https://doi.org/10.1063/10.0031330.

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The absorption of electromagnetic waves at low temperatures in metals filled with helium has been studied theoretically in the region of the atomic helium 1S0–21P1 transition. It is suggested that as a result of the high pressure the helium in the pores exists in the crystallized form and its excited states are excitons. The permittivity of a medium containing pores with helium has been found. The frequency dependence of the absorption contains maxima produced by the discrete nature of the exciton spectrum in a pore. The most intense resonances in the absorption occur for those discrete levels

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11

HOFFMANN, M., T. HASCHE, K. SCHMIDT, T. W. CANZLER, V. M. AGRANOVICH, and K. LEO. "EXCITONS IN QUASI-ONE-DIMENSIONAL CRYSTALLINE PERYLENE DERIVATIVES: BAND STRUCTURE AND RELAXATION DYNAMICS." International Journal of Modern Physics B 15, no. 28n30 (2001): 3597–600. http://dx.doi.org/10.1142/s0217979201008238.

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The exciton structure of crystalline MePTCDI (N-N'-dimethylperylene-3,4,9,10-dicarboximide) is modeled by a one-dimensional Hamiltonian, which includes the interactions between Frenkel excitons with several vibronic levels and charge-transfer excitons. Using appropriate fitting parameters, which are verified by quantum chemical calculations, this model can explain the main features of the low temperature absorption spectrum. Polarized absorption spectra show different polarization ratios for the various peaks. This polarization behavior is explained by the varying contribution of the charge-tr

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12

AHARONYAN, K. H., and E. M. KAZARYAN. "THE EFFECT OF SCREENED COULOMB INTERACTION ON THE OPTICAL PROPERTIES OF EuS/PbS/EuS FINITE CONFINING POTENTIAL QUANTUM WELL." International Journal of Modern Physics: Conference Series 15 (January 2012): 224–31. http://dx.doi.org/10.1142/s201019451200935x.

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We theoretically investigate excitonic effects on the optical properties of quasi-two dimensional realistic EuS/PbS/EuS finite confining potential quantum well. The strong contrast of material parameter’s across the well interfaces and the characteristic band-nonparabolicity effect of lead salt semiconductor are taken into account. In presence of medium polarization a feasibility of the screened Coulomb potential in quantum well is examined and appropriate screening radius is revealed for the first time. The screened binding energy investigated while a variational approach has been used. Depen

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13

Pokytnii, S. I., and A. D. Terets. "Optical absorption by titanium dioxide nanocrystals." Himia, Fizika ta Tehnologia Poverhni 14, no. 3 (2023): 383–86. http://dx.doi.org/10.15407/hftp14.03.383.

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Using a variational method within the framework of the effective mass approximation, using a triangular coordinate system of an electron, hole, and exciton moving in a titanium dioxide quantum dot, the exciton energy spectrum was obtained as a function of the radius a of the quantum dot. The variational wave function of the exciton contained factors that took into account the motion of an electron and a hole in a potential well of infinite depth of a quantum dot, as well as the form of a hydrogen-like wave function. It is shown that the occurrence of an exciton in a quantum dot has a threshold

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14

Ropakova, I. Yu, and A. A. Zvyagin. "Role of inhomogeneities in resonance light absorption and luminescence of molecular aggregates." Low Temperature Physics 49, no. 2 (2023): 221–27. http://dx.doi.org/10.1063/10.0016874.

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Within the linear response theory, we have calculated the resonance absorption of the light and resonance luminescence for the one-dimensional molecular aggregate. We have shown that the randomness of the distribution of signs of the interaction between dipoles of the aggregate dramatically changes the parameters of the absorption and luminescence. In the homogeneous case, the resonance response of the exciton band of the molecular aggregate produces narrow lines at edges of the band. On the other hand, inhomogeneities yield contributions to optical characteristics of all excitons of the band.

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15

Ryabchuk, Vladimir. "Photophysical processes related to photoadsorption and photocatalysis on wide band gap solids: A review." International Journal of Photoenergy 6, no. 3 (2004): 95–113. http://dx.doi.org/10.1155/s1110662x04000145.

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During the last two decades, various pathways describing photoexcitation of small molecules’ surface reactions at the wide band gap metal oxides and halides (Eg>3eV) have been recognized. Photogeneration of excitons and free charge carriers may occur in bands of: i) fundamental absorption; ii) extrinsic and intrinsic defect absorption, including those related to surface states; and iii) in UV-induced color centers. Considerable red shifts relative to the fundamental absorption threshold of wide band gap solids have been observed for the spectral limits of surface photoreactions induced in e

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16

AOKI-MATSUMOTO, T., K. FURUTA, T. YAMADA, H. MORIYA, K. MIZUNO, and A. H. MATSUI. "EXCITONIC PHOTOLUMINESCENCE IN PENTACENE SINGLE CRYSTAL." International Journal of Modern Physics B 15, no. 28n30 (2001): 3753–56. http://dx.doi.org/10.1142/s0217979201008585.

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Photoluminescence of pentacene single crystals is studied in the temperature range of 7 K to 200 K under excitation with He-Ne laser light. Photoluminescence spectra consist of four broad bands, L1 to L4. The highest energy band, L1, located close to the lowest exciton absorption band mainly appears for //b-polarization. The intensity of the second one, L2, with Stokes-shift of about 1500 cm -1, decreases as temperature rises above 30 K and disappears at 100 K. The bands, L3 and L4, which are located at lower energy, are observed at higher temperatures up to 200 K. Based on their energy positi

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17

Ketan, Dodiya, Agravat Sagar, and A.T.Oza. "FTIR Spectra of Ni H dmg 2 Hydrogen Bonded With Six Dyes." International Journal of Trend in Scientific Research and Development 1, no. 2 (2017): 14–22. https://doi.org/10.31142/ijtsrd63.

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Here the one dimensional semiconductor namely bis dimethyiglyoximato Ni is hydrogen bonded with 6 highly polarizable dyes which are Para red, Congo red, Direct red, Bismark brown, Evans blue and Trypan blue. The hydrogen bonding was verified with FTIR spectroscopy. FTIR specra also reveal modification of absorption edges by exciton phonon coupling there are threshold energies for the formation of free excitons and electron hole pairs with phonon emissions in the intrinsic absorption edge spectrum. The remainder absorption at the value of the band gap is proportional to the exciton ionization e

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18

Yamanaka, K., K. Edamatsu, and T. Itoh. "Photoinduced infrared absorption spectra of CuCl quantum dots in NaCl." International Journal of Modern Physics B 15, no. 28n30 (2001): 4005–8. http://dx.doi.org/10.1142/s0217979201009219.

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We have studied infrared transient absorption spectra of CuCl QDs grown inside a NaCl matrix under tunable UV laser excitation on resonance with the confined excitons. In addition to the transient excited-state absorption, there appears induced IR absorption with lifetime much longer than that of the confined exciton. The peak energy remains at ~0.3 eV regardless of the QD size. The optical density is proportional to the square root of the UV laser power. The decay of the induced absorption is logarithmic on time and is accelerated by the irradiation of light below the band gap. We assign this

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19

Pugžlys, A., P. R. Hania, C. Didraga, J. Knoester, and K. Duppen. "Cylindrical Aggregates of TDBC: Linear and Nonlinear Optical Properties Versus Morphology." Solid State Phenomena 97-98 (April 2004): 201–6. http://dx.doi.org/10.4028/www.scientific.net/ssp.97-98.201.

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The linear and nonlinear optical properties of pure 3,3'-bis(3-carboxypropyl)-5,5',6,6'- tetrachloro-1,1'-dioctylbenzimidacarbocyanine (C8O3) aggregates as well as of C8O3 aggregates in the presence of PVA are studied at room temperature. The obtained results reveal that absorption spectra of both aggregates are governed by four absorption bands. Three of these represent transitions having dipole moments oriented parallel to the axis of the aggregate and one oriented perpendicular to it. The two lower energy parallel transitions are found to be weakly coupled which suggests that they represent

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20

Kuno, Ken. "(Invited) A Polaron Paradigm for Perovskite Nanocrystal Emitting States." ECS Meeting Abstracts MA2024-02, no. 35 (2024): 2452. https://doi.org/10.1149/ma2024-02352452mtgabs.

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Perovskite nanocrystals (NCs) such as those made from CsPbBr3 have numerous uses. Most involve exploiting their light emission and are motivated by their defect tolerance and large, as-made emission quantum yields (QYs). For the latter, near unity QYs are possible. This leads to ready applications as light emitters but also intriguingly to possible material platforms for demonstrating semiconductor-based optical refrigeration. Absent, though, is a fundamental understanding of perovskite NC emitting states, central to these applications. Of particular note are observations of near-universal, si

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21

Lincoln, Craig N., Matthias Block, Bastian Baudisch, et al. "Exciton-Exciton Annihilation as a Mechanism for Uphill Transfer in a Molecular Excitonic System." EPJ Web of Conferences 205 (2019): 06017. http://dx.doi.org/10.1051/epjconf/201920506017.

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Exciton dynamics in a HJ-aggregate of cyanine dye TTBC are investigated by transient absorption with a time resolution of <60 fs and power-dependent emission spectroscopies. Both measurements are consistent with an exciton delocalization length of ~28 monomers. A model assuming diffusive exciton motion reveals that the exciton mobility is at least bimodal and restricted to one spatial dimension. J-band diffusion rates of 2.69 and 2.79e-3 cm2s-1 are found, leading to maximal diffusion lengths of 449 and 14.5 nm. The findings indicate that exciton-exciton annihilation is the origin of effecti

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22

Fang, Nan, Yih-Ren Chang, Daiki Yamashita, et al. "(Invited) Resonant Exciton Transfer in Mixed-Dimensional Heterostructures for Overcoming Dimensional Restrictions in Optical Processes." ECS Meeting Abstracts MA2024-01, no. 9 (2024): 898. http://dx.doi.org/10.1149/ma2024-019898mtgabs.

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Nanomaterials exhibit unique optical phenomena, in particular excitonic quantum processes occurring at room temperature. The low dimensionality, however, imposes strict requirements for conventional optical excitation, and an approach for bypassing such restrictions is desirable. Here we report on exciton transfer in carbon-nanotube/tungsten-diselenide heterostructures, where band alignment can be systematically varied. The mixed-dimensional heterostructures display a pronounced exciton reservoir effect where the longer-lifetime excitons within the two-dimensional semiconductor are funneled in

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23

RATH, S., A. K. DASH, S. N. SAHU, and S. NOZAKI. "QUANTUM CONFINEMENT EFFECT IN HgTe NANOCRYSTALS AND VISIBLE LUMINESCENCE." International Journal of Nanoscience 03, no. 03 (2004): 393–401. http://dx.doi.org/10.1142/s0219581x04002176.

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Mercury Telluride ( HgTe ) nanocrystals with a mean size of 5.35 nm have been synthesized by an electrochemical technique. Structural analysis by transmission electron microscopy and glancing angle X-ray diffraction studies indicate the presence of cubic phase HgTe nanocrystals in the deposit. Optical absorption measurements reveal two well resolved excitonic peaks around 578.5 nm and 550 nm attributed to heavy hole valence band (HVB)–conduction band (CB) and light hole valence band (LVB)–CB transitions, respectively, and suggest a band opening of bulk inverted narrow band gap HgTe as a result

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24

QUANG, NGUYEN HONG. "THE OPTICAL STARK EFFECT OF THE EXCITON DUE TO DYNAMICAL COUPLING BETWEEN QUANTIZED STATES OF THE ELECTRON AND HOLE IN QUANTUM WELLS." International Journal of Modern Physics B 07, no. 19 (1993): 3405–13. http://dx.doi.org/10.1142/s0217979293003280.

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Optical Stark effect of the exciton in quantum wells is treated by taking into account not only dynamical coupling by pump field between quantized states of the electron in the conduction band but also the coupling between quantized states of the hole in the valence band. The changes in the calculated one-photon absorption probability by exciton depend essentially on pump field detuning.

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25

Zhu, Lang, Zongpeng Song, Ran Li, and Haiou Zhu. "Hot carrier dynamics in MoS₂/WS₂ heterostructure." Nanotechnology 33, no. 19 (2022): 195701. http://dx.doi.org/10.1088/1361-6528/ac4e41.

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Abstract TMDs based heterostructure have drawn much attention for its potential application in photoelectric devices benefiting from the rapid and effective carrier separation and ultra-long interlayer exciton lifetime. Recent studies on carrier dynamics of TMDs based heterostructures are mainly focused on the transfer process of photo-generated carriers across the interface and lifetime of interlayer exciton but little attention is paid on the dynamics of hot carriers. Here, the carrier dynamics of hot carriers in MoS2/WS2 heterostructure is investigated by transient absorption spectra. Rapid

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26

Cherepanov, D. A., K. V. Neverov, Yu N. Obukhov, et al. "Photochemical reactions of chlorophyll tetramer in water-soluble chlorophyll-binding protein BoWSCP." Биохимия 88, no. 10 (2023): 1908–25. http://dx.doi.org/10.31857/s0320972523100135.

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The absorption dynamics of chlorophyll a in a symmetric tetrameric complex of the water-soluble chlorophyll-binding protein BoWSCP was measured by the broadband femtosecond laser pump-probe spectroscopy within the range from 400 to 780 nm with a time resolution of 20 f-200 ps. When BoWSCP was excited in the region of the Soret band at a wavelength of 430 nm, a nonradiative intramolecular conversion S3 → S1 was observed with a characteristic time of 83 ± 9 fs. When the complex was excited in the region of the Qy band at a wavelength of 670 nm, a relaxation transition between two excitonic state

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27

Grevtseva, Irina G., Mikhail S. Smirnov, Kirill S. Chirkov, and Oleg V. Ovchinnikov. "Trap state and exciton luminescence of colloidal PbS quantum dots coated with thioglycolic acid molecules." Kondensirovannye sredy i mezhfaznye granitsy = Condensed Matter and Interphases 25, no. 2 (2023): 182–89. http://dx.doi.org/10.17308/kcmf.2023.25/11099.

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This work presents the results of studying the IR luminescence of colloid PbS quantum dots coated with molecules of thioglycolic acid. Luminescence of the sample was recorded using the InGaAs image sensor PDF 10C/M (ThorlabsInc., USA) and a diffraction monochromator with 600 mm-1 grating. To study the temperature dependence of luminescence, the sample was cooled in a nitrogen cryostat down to 80 К. A redistribution of the luminescence intensity between two peaks (1100 and 1280 nm) was identified upon a decrease in temperature. It was shown that an exciton absorption peak was present in the exc

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28

Itoh, Chihiro. "Optical study on relaxation of excitons and initiation of photopolymerization in diacetylene crystals at low temperatures." International Journal of Photoenergy 1, no. 3 (1999): 147–51. http://dx.doi.org/10.1155/s1110662x99000252.

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Luminescence and optical absorption induced by irradiating with a pulse of 266nm laser beam have been measured in 5,7-dodecadiyne-1,12-diol bis[phenyl carbamate] (DA-TCDU). In addition to the recombination luminescence of the lowest triplet state, luminescence from the excited single state is identified. Irradiation with a pulse of 266 nm laser beam having the fluence above 4.4mJcm-2leads to formation of series of optical absorption bands at 3.05 eV, 2.52 eV and 2.18 eV, which are ascribed to the optical transition due to dimer diradicals, trimer diradicals and the tetramer diradicals, respect

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29

Kuno, Ken. "(Invited) A Polaron Paradigm for Perovskite Nanocrystal Emitting States." ECS Meeting Abstracts MA2024-01, no. 13 (2024): 1088. http://dx.doi.org/10.1149/ma2024-01131088mtgabs.

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Perovskite NCs such as CsPbBr3 have numerous uses. Most involve exploiting their light emission and are motivated by their defect tolerance and large, as-made emission quantum yields. Absent, though, is a fundamental understanding of perovskite NC emitting states, central to these applications. Of particular note are observations of near-universal, size-, temperature-, and composition-dependent absorption/emission Stokes shifts where observed energy differences are between absorbing and emitting states. Very little is known about the origin of these shifts. Moreover, little is known about the

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30

Трофимова, Н. Б., А. Г. Роках, А. О. Бочкарев та М. И. Шишкин. "Экситонные линии поглощения PbS в композите CdS-PbS". Письма в журнал технической физики 44, № 7 (2018): 78. http://dx.doi.org/10.21883/pjtf.2018.07.45888.17011.

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AbstractThe spectral dependences of transmission, absorption, and reflection in CdS−PbS semiconductor layers, which are promising for the development of photodetectors and emitters in the region of an atmospheric- transparency window, were studied. It has been established that a series of thin lines are observed in the infrared spectrum on an absorption edge of the narrow-gap phase (PbS). A method for identification of exciton series was used, and exciton-binding energy E _ ex , exciton concentration N , and value of valence-band splitting Δ E _ v were determined.

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Poudel, Yuba, Sairaman Seetharaman, Swastik Kar, Francis D’Souza, and Arup Neogi. "Plasmon-Induced Enhanced Light Emission and Ultrafast Carrier Dynamics in a Tunable Molybdenum Disulfide-Gallium Nitride Heterostructure." Materials 15, no. 21 (2022): 7422. http://dx.doi.org/10.3390/ma15217422.

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The effect of localized plasmon on the photoemission and absorption in hybrid molybdenum disulfide-Gallium nitride (MoS2-GaN) heterostructure has been studied. Localized plasmon induced by platinum nanoparticles was resonantly coupled to the bandedge states of GaN to enhance the UV emission from the hybrid semiconductor system. The presence of the platinum nanoparticles also increases the effective absorption and the transient gain of the excitonic absorption in MoS2. Localized plasmons were also resonantly coupled to the defect states of GaN and the exciton states using gold nanoparticles. Th

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32

Tikhomirov, S. A. "Ultrafast dynamics and mechanisms of non-stationary absorption in thin gallium selenide samples." Proceedings of the National Academy of Sciences of Belarus. Physics and Mathematics Series 57, no. 1 (2021): 99–107. http://dx.doi.org/10.29235/1561-2430-2021-57-1-99-107.

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Herein, the dynamics and mechanisms of induced absorption in thin samples of gallium selenide under various excitation conditions are studied using femtosecond kinetic spectroscopy. We have registered several types of induced changes including induced absorption on free charge carriers (“hot” and thermalized electrons), bleaching and absorption due to the population of near-edge trap or exciton states, as well as rapid changes in the absorption of probing radiation in the region of the overlap of the exciting and probing pulses due to two-quantum two-frequency interband transitions. The time r

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33

Kondryuk, D. V. "Temperature changes in the exciton absorption band observed in flat double nanoheterostructures GaAs/AlxGa1-xAs." Semiconductor Physics Quantum Electronics and Optoelectronics 18, no. 2 (2015): 128–33. http://dx.doi.org/10.15407/spqeo18.02.128.

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GOYAL, SWATI, and PRANAY K. SEN. "BIEXCITONIC EFFECT ON TRANSIENT NONLINEAR REFRACTION AND ABSORPTION IN A MAGNETIZED CdS QUANTUM DOTS." International Journal of Nanoscience 10, no. 04n05 (2011): 675–79. http://dx.doi.org/10.1142/s0219581x11009143.

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Transient optical nonlinearities of semiconductor quantum dots in the strongly confined regime are studied, in which the exciton, biexciton and magnetic field effects are taken into account. The photo induced band-to-band electronic transitions are considered from both the heavy-hole (hh) and light-hole (lh) valence bands to the lowest (1s) exciton state below the fundamental absorption edge. The time dependent perturbation technique for a three-level system, under the near band gap resonant excitation regime, has been employed; with the incorporation of the relaxation and dephasing mechanisms

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Zhai, Yaxin, Chuanxiang Sheng та Z. Valy Vardeny. "Singlet fission of hot excitons in π -conjugated polymers". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 373, № 2044 (2015): 20140327. http://dx.doi.org/10.1098/rsta.2014.0327.

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We used steady-state photoinduced absorption (PA), excitation dependence (EXPA( ω )) spectrum of the triplet exciton PA band, and its magneto-PA (MPA( B )) response to investigate singlet fission (SF) of hot excitons into two separated triplet excitons, in two luminescent and non-luminescent π -conjugated polymers. From the high energy step in the triplet EXPA( ω ) spectrum of the luminescent polymer poly(dioctyloxy)phenylenevinylene (DOO-PPV) films, we identified a hot-exciton SF (HE-SF) process having threshold energy at E ≈2 E T (=2.8 eV, where E T is the energy of the lowest lying triplet

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Klahold, Walter, Charles Tabachnick, Gabriel Freedman, Robert P. Devaty, and Wolfgang J. Choyke. "New Evidence for the Second Conduction Band in 4H SiC." Materials Science Forum 897 (May 2017): 250–53. http://dx.doi.org/10.4028/www.scientific.net/msf.897.250.

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Differential absorption measurements were taken on ultra-pure boule pieces and epitaxial films of 4H SiC. The energy range of particular interest is from 3.40 eV to 3.52 eV. The free exciton energy gap associated with the second lowest conduction band at the M point in the Brillouin zone was determined to be EGX-2 = 3.4107 eV. This value is obtained from phonon assisted free exciton transitions involving the second conduction band measured in transmission with polarization E⊥c. The energy separation of the two lowest conduction bands is determined to be 144 ± 2 meV. Some replica peaks attribut

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Gavalajyan, Sargis P., Grigor A. Mantashian, Gor Ts Kharatyan, et al. "Optical Properties of Conical Quantum Dot: Exciton-Related Raman Scattering, Interband Absorption and Photoluminescence." Nanomaterials 13, no. 8 (2023): 1393. http://dx.doi.org/10.3390/nano13081393.

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The current work used the effective mass approximation conjoined with the finite element method to study the exciton states in a conical GaAs quantum dot. In particular, the dependence of the exciton energy on the geometrical parameters of a conical quantum dot has been studied. Once the one-particle eigenvalue equations have been solved, both for electrons and holes, the available information on energies and wave functions is used as input to calculate exciton energy and the effective band gap of the system. The lifetime of an exciton in a conical quantum dot has been estimated and shown to b

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Labzovskaya M. E., Novikov B. V., Serov A. Yu., et al. "Optical properties of Cu-=SUB=-2-=/SUB=-O nanowhiskers." Semiconductors 56, no. 11 (2022): 849. http://dx.doi.org/10.21883/sc.2022.11.55026.4272.

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The optical properties of Cu2O nanowhiskers grown by the liquid method with material deposition in an electric field have been studied. The spectral lines forbidden by the selection rules for perfect Cu2O crystals were found in the Raman spectra. The nature of related phonon states is analyzed. In the photoluminescence spectra in the red and near-IR regions, broad bands of defective origin are observed. It was found that the presence of a band at 650 nm (1.9 eV) is a specific feature of the photoluminescence of nanowhiskers. Its properties are studied and possible radiation mechanisms are disc

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Sorokin, O. V., I. I. Grankina, I. I. Bespalova, and S. L. Yefimova. "Features of plasmonic enhancement of luminescence of molecular aggregates of cyanine dyes." Journal of V. N. Karazin Kharkiv National University, Series "Physics", no. 39 (November 30, 2023): 26–39. https://doi.org/10.26565/2222-5617-2023-39-02.

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The article examines the effect of plasmon resonance of gold nanoparticles on the luminescent properties of molecular aggregates (J-aggregates) of two cyanine dyes, PIC and TDBC. It is shown that the luminescence enhancement of J-aggregates due to the exciton-plasmon interaction occurs in a very similar manner for both types of aggregates, namely: the largest enhancement factor is achieved at a distance between J-aggregates and nanoparticles of 15-20 nm, while the exciton delocalization length increases and increasing their lifetime, as well as suppressing the process of exciton self-trapping.

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Baldini, Edoardo, Tania Palmieri, Enrico Pomarico, Gerald Auböck, and Majed Chergui. "Electron Dynamics in Anatase TiO2 Nanoparticles by Ultrafast Broadband Deep-Ultraviolet Spectroscopy." EPJ Web of Conferences 205 (2019): 05017. http://dx.doi.org/10.1051/epjconf/201920505017.

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The optical bandgap of anatase TiO2 nanoparticles is dominated by bulk absorption bands in the deep-ultraviolet due to strongly bound excitons. These spectral features can be utilized as a sensitive probe of carrier and lattice dynamics inside the TiO2 nanoparticles. Here, we implement ultrafast broadband spectroscopy tuned to the exciton resonances in order to track the electron cooling in the conduction band of bare anatase nanoparticles and monitor the electron injection dynamics from an external dye in the case of sensitized anatase nanoparticles.

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Rahman, Md Bulu, Ahatashamul Islam, and Toshifumi Iimori. "Exciton Delocalization and Polarizability in Perylenetetracarboxylic Diimide Probed Using Electroabsorption and Fluorescence Spectroscopies." Molecules 29, no. 10 (2024): 2206. http://dx.doi.org/10.3390/molecules29102206.

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Perylenetetracarboxylic diimide (PTCDI) is an n-type organic semiconductor molecule that has been widely utilized in numerous applications such as photocatalysis and field-effect transistors. Polarizability and dipole moment, which are inherent properties of molecules, are important parameters that determine their responses to external electric and optical fields, physical properties, and reactivity. These parameters are fundamentally important for the design of innovative materials. In this study, the effects of external electric fields on absorption and fluorescence spectra were investigated

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Savchenko, Sergey S., and Ilya A. Weinstein. "Inhomogeneous Broadening of the Exciton Band in Optical Absorption Spectra of InP/ZnS Nanocrystals." Nanomaterials 9, no. 5 (2019): 716. http://dx.doi.org/10.3390/nano9050716.

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In this work, we have simulated the processes of broadening the first exciton band in optical absorption spectra (OA) for InP/ZnS ensembles of colloidal quantum dots (QDs). A phenomenological model has been proposed that takes into account the effects of the exciton–phonon interaction, and allows one to analyze the influence of the static and dynamic types of atomic disorder on the temperature changes in the spectral characteristics in question. To vary the degree of static disorder in the model system, we have used a parameter δ, which characterizes the QD dispersion in size over the ensemble

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Fujimoto, Yutaka, Masanori Koshimizu, Hiroki Kawamoto, Kenichi Watanabe, Akio Miyamoto, and Keisuke Asai. "Luminescence and Scintillation Properties of YAl3(BO3)4 Single Crystal for Thermal Neutron Detection." Crystals 15, no. 4 (2025): 357. https://doi.org/10.3390/cryst15040357.

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A single crystal of YAl3(BO3)4 was grown using the top-seeded solution growth method. The vacuum ultraviolet (VUV) excitation spectrum, monitored at the emission wavelength of 312 and 372 nm, showed a narrow excitation band at around 162 nm, which is located near the absorption edge of the YAl3(BO3)4 host. Upon VUV excitation at 162 nm, the characteristic self-trapped exciton (STE) emission bands were observed at 312 and 372 nm. The X-ray excited scintillation spectrum shows a broad emission band peaking at 310 nm with a weak shoulder band at around 375 nm, which is consistent with photolumine

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Огородников, И. Н., та В. А. Пустоваров. "Природа аномальной красной люминесценции в нелинейно-оптических кристаллах K-=SUB=-2-=/SUB=-Al-=SUB=-2-=/SUB=-B-=SUB=-2-=/SUB=-O-=SUB=-7-=/SUB=- : Fe". Физика твердого тела 61, № 5 (2019): 876. http://dx.doi.org/10.21883/ftt.2019.05.47584.14f.

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In this work, the spectra of anomalously intense luminescence at 1.675 eV (FWHM= 0.173 eV) in wide-gap (180–3600 nm) nonlinear-optical crystals K2Al2B2O7 were observed experimentally for the first time upon excitation in the spectral region of 4–5 harmonics of the fundamental frequency of the Nd3+ radiation. Using low-temperature (7–293 K) luminescence-optical spectroscopy with selective excitation by synchrotron radiation, it was shown that red luminescence occurs at intracenter 4T1(4G)→ 6A1(6S) transitions in impurity Fe3+ ions with a concentration less than 2 ppm. The high excitation effici

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Kitagawa, Yuichi, Junji Hiromoto, and Kazuyuki Ishii. "Electronic absorption, MCD, and luminescence properties of porphyrin J-aggregates." Journal of Porphyrins and Phthalocyanines 17, no. 08n09 (2013): 703–11. http://dx.doi.org/10.1142/s1088424613500090.

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In this paper, we have investigated electronic absorption, magnetic circular dichroism, fluorescence, and phosphorescence spectra for a protonated form of H 2 TPPS 4( H 4 TPPS 4) and the J-aggregates of H 4 TPPS 4. The J-aggregation induces a large red-shift in the B (Soret) and Q absorption bands, while the phosphorescence peaks of H 4 TPPS 4 and its J-aggregates are almost entirely similar. The large red-shift of the B-band is quantitatively explained by the exciton interactions. Thus, the exciton interactions in the J-aggregates are proposed as a useful approach to decrease the energy split

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Eremenko, A. V., I. S. Kachur, V. G. Piryatinskaya, and V. V. Slavin. "Effect of spin-wave spectral structure of antiferromagnetic crystals on thermal broadening of exciton absorption bands." Soviet Journal of Low Temperature Physics 18, no. 4 (1992): 258–61. https://doi.org/10.1063/10.0033134.

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Temperature dependences of exciton absorption band half-widths are studied experimentally and theoretically for antiferromagnets with different dimensions of magnetic structures and spin wave spectra. In a 3D AFM with a gapless dispersion of spin waves, the exciton band half-width δ(T)∝T3 In the presence of an energy gap ε˙g in the magnon spectrum, δ(T)∝Tn−1Snεg/T , where Snεg/T=∑l=1∞l1−nexp−εgl/kBTn is the magnetic structure dimension, and kB is Boltzmann’s constant. The obtained expressions for AFM crystals with a gap in the spin-wave spectrum reflect the threshold nature of the δ(T) depende

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Rao, Yifan, Fusheng Zhang, Bao Zhu, et al. "A C2N/ZnSe heterostructure with type-II band alignment and excellent photocatalytic water splitting performance." New Journal of Chemistry 45, no. 30 (2021): 13571–78. http://dx.doi.org/10.1039/d1nj02366g.

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Gao, Yongsheng, Yuanzheng Li, Weizhen Liu, et al. "Unique High-Energy Excitons in Two-Dimensional Transition Metal Dichalcogenides." Chinese Physics B, June 4, 2025. https://doi.org/10.1088/1674-1056/ade074.

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Abstract Two-dimensional (2D) transition metal dichalcogenides (TMDs), endowed with exceptional lightmatter interaction strength, have become a pivotal platform in advanced optoelectronics, enabling atomically precise control of excitonic phenomena and offering transformative potential for engineering next-generation optoelectronic devices. In contrast to the narrowband absorption characteristics of conventional band-edge excitons, which are limited by the bandgap energy, highenergy excitons not only demonstrate broad momentum matching capability in the ultraviolet regime due to band nesting e

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Schwinn, Madison C., Shahnawaz Rafiq, Changmin Lee, et al. "Charge Transfer Dynamics and Interlayer Exciton Formation in MoS₂/VOPc Mixed Dimensional Heterojunction." Journal of Chemical Physics, October 20, 2022. http://dx.doi.org/10.1063/5.0107791.

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Mixed-dimensional van der Waals heterojunctions involve interfacing materials with different dimensionalities, such as a 2D transition metal dichalcogenide (TMD) and a 0D organic semiconductor. These heterojunctions have shown unique interfacial properties not found in either individual components. Here, we use femtosecond transient absorption to reveal photoinduced charge transfer and interlayer exciton formation in a mixed-dimensional heterojunction between monolayer MoS2 and vanadyl phthalocyanine (VOPc). We find that hole transfer occurs from the MoS2 valence band to VOPc in ~710 fs, while

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Liang, Yufeng, and Li Yang. "Electronic Structure and Optical Absorption of Fluorographene." MRS Proceedings 1370 (2011). http://dx.doi.org/10.1557/opl.2011.894.

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ABSTRACTA first-principles study on the quasiparticles energy and optical absorption spectrum of fluorographene is presented by employing the GW + Bethe-Salpeter Equation (BSE) method with many-electron effects included. The calculated band gap is increased from 3.0 eV to 7.3 eV by the GW approximation. Moreover, the optical absorption spectrum of fluorographene is dominated by enhanced excitonic effects. The prominent absorption peak is dictated by bright resonant excitons around 9.0 eV that exhibit a strong charge transfer character, shedding light on the exciton condensation and relevant op

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