Temperature dependence of excitonic emission in cubic CdSe thin film

Chia, C. H.; Yuan, Chi‐Tsu; Ku, Jui Tai; Yang, Song; Chou, Wu–Ching; Juang, Jenh‐Yih; Hsieh, Shelly; Chiu, Kuan−Cheng; Hsu, Jy-Shan; Jeng, Syang Ywan

doi:10.1016/j.jlumin.2007.06.003

Cited by 27 publications

(21 citation statements)

References 25 publications

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“…This elevated E exc (0) compared with the bulk-like ZB CdSe epilayers (1.739 eV) 47 is due to increased quantum confinement effects. Further, we obtain a ep = 18.2 ± 2.8 meV and Θ = 36 ± 0.4 K. Chia et al 47 calculated a ep = 21 meV for bulk-like ZB CdSe epilayers. This shows that the increased confinement in the NPLs has reduced the average exciton-phonon coupling, which is also evident from the significant reduction in average phonon temperature of 305 K in bulk ZB CdSe.…”

Section: −T/τ2mentioning

confidence: 95%

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Temperature-dependent optoelectronic properties of quasi-2D colloidal cadmium selenide nanoplatelets

et al. 2017

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Colloidal cadmium selenide (CdSe) nanoplatelets (NPLs) are a recently developed class of efficient luminescent nanomaterials suitable for optoelectronic device applications. A change in temperature greatly affects their electronic bandstructure and luminescence properties. It is important to understand how and why the characteristics of NPLs are influenced, particularly at elevated temperatures, where both reversible and irreversible quenching processes come into the picture. Here we present a study of the effect of elevated temperatures on the characteristics of colloidal CdSe NPLs. We used an effective-mass envelope function theory based 8-band k·p model and density-matrix theory considering exciton-phonon interaction. We observed the photoluminescence (PL) spectra at various temperatures for their photon emission energy, PL linewidth and intensity by considering the exciton-phonon interaction with both acoustic and optical phonons using Bose-Einstein statistical factors. With a rise in temperature we observed a fall in the transition energy (emission redshift), matrix element, Fermi factor and quasi Fermi separation, with a reduction in intraband state gaps and increased interband coupling. Also, there was a fall in the PL intensity, along with spectral broadening due to an intraband scattering effect. The predicted transition energy values and simulated PL spectra at varying temperatures exhibit appreciable consistency with the experimental results. Our findings have important implications for the application of NPLs in optoelectronic devices, such as NPL lasers and LEDs, operating much above room temperature.

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Section: −T/τ2mentioning

confidence: 95%

“…49 Furthermore, with increasing temperature, we also have a substantial reduction in the PL intensity as the excitons are trapped in the nonradiative centers, likely at NPL surfaces and dissociate into the continuum states. The integrated intensity of the PL spectra with varying temperatures is given by 47,52 IðTÞ…”

Section: −T/τ2mentioning

confidence: 99%

Temperature-dependent optoelectronic properties of quasi-2D colloidal cadmium selenide nanoplatelets

et al. 2017

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“…The coupling to optical modes tends to increase with A and then saturate for large platelet areas towards values reported by Chia et al for laterally infinite MBE grown CdSe epilayers (≈20 meV). 67 As the Fröhlich interaction is considered the dominating mechanism 42 for the LO phonon coupling in polar semiconductor nano-structures we briefly investigate whether this can explain the observed complicated behavior directly. The corresponding interaction potential 59…”

Section: Nanoscale Papermentioning

confidence: 99%

A comparative study demonstrates strong size tunability of carrier–phonon coupling in CdSe-based 2D and 0D nanocrystals

et al. 2019

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“…One more anomalous feature of the DPL band can be seen from this figure. In particular, a pronounced redshift of the DPL band is observed for all samples ( Figure 9 a), contrary to the well-established PL behavior upon decreasing temperature, which includes blue shift and narrowing of PL bands [ 55 , 56 ]. We attribute this rather anomalous behavior to the suppressed thermal occupation of higher-energy trap states, resulting in a lower average energy of the occupied trap states at lower temperature, and thus a lower energy of the PL maximum.…”

Section: Resultsmentioning

confidence: 58%

Photoinduced Enhancement of Photoluminescence of Colloidal II-VI Nanocrystals in Polymer Matrices

et al. 2020

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The environment strongly affects both the fundamental physical properties of semiconductor nanocrystals (NCs) and their functionality. Embedding NCs in polymer matrices is an efficient way to create a desirable NC environment needed for tailoring the NC properties and protecting NCs from adverse environmental factors. Luminescent NCs in optically transparent polymers have been investigated due to their perspective applications in photonics and bio-imaging. Here, we report on the manifestations of photo-induced enhancement of photoluminescence (PL) of aqueous colloidal NCs embedded in water-soluble polymers. Based on the comparison of results obtained on bare and core/shell NCs, NCs of different compounds (CdSe, CdTe, ZnO) as well as different embedding polymers, we conclude on the most probable mechanism of the photoenhancement for these sorts of systems. Contrary to photoenhancement observed earlier as a result of surface photocorrosion, we do not observe any change in peak position and width of the excitonic PL. Therefore, we suggest that the saturation of trap states by accumulated photo-excited charges plays a key role in the observed enhancement of the radiative recombination. This suggestion is supported by the unique temperature dependence of the trap PL band as well as by power-dependent PL measurement.

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Temperature dependence of excitonic emission in cubic CdSe thin film

Cited by 27 publications

References 25 publications

Temperature-dependent optoelectronic properties of quasi-2D colloidal cadmium selenide nanoplatelets

Temperature-dependent optoelectronic properties of quasi-2D colloidal cadmium selenide nanoplatelets

A comparative study demonstrates strong size tunability of carrier–phonon coupling in CdSe-based 2D and 0D nanocrystals

Photoinduced Enhancement of Photoluminescence of Colloidal II-VI Nanocrystals in Polymer Matrices

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