Spectral Dependencies of the Stretched Exponential Dispersion Factor and Photoluminescence Quantum Yield as a Common Feature of Nanocrystalline Si

0540637 - MBÚ 2021 RIV DE eng J - Journal Article
Greben, M. - Khoroshyy, Petro - Valenta, J.
Spectral Dependencies of the Stretched Exponential Dispersion Factor and Photoluminescence Quantum Yield as a Common Feature of Nanocrystalline Si.
Physica Status Solidi A. Roč. 217, č. 4 (2020), č. článku 1900698. ISSN 1862-6300. E-ISSN 1862-6319
Institutional support: RVO:61388971
Keywords : dispersion factors * quantum yield * rate/lifetime distribution * silicon nanocrystals * stretched exponential functions
OECD category: Biophysics
Impact factor: 1.981, year: 2020
Method of publishing: Limited access
https://onlinelibrary.wiley.com/doi/abs/10.1002/pssa.201900698

Herein, the spectral dependencies of the dispersion factor Beta (from the stretched exponential function) and photoluminescence (PL) quantum yield (QY) of silicon nanocrystals (Si NCs) are thoroughly studied. Spectrally resolved PL decay kinetics of Si NCs in both liquid and solid samples are measured and their corresponding distributions of rates are retrieved by means of the hybrid maximum-entropy method. This enables us to demonstrate a direct correlation of dispersion factor β with the width of rate distribution. Here, the evidence of the same step-like spectral dependence of rate distribution widths (dispersion factor) for different forms of nanocrystalline silicon (including porous silicon and chemically synthesized Si NCs) is presented suggesting intrinsic (core-related) origin of rate distributions. Spectral dependence of normalized QY of Si NCs reveals two characteristic peaks with spectral positions at ≈1.42 and ≈1.68 eV. A similar peak in QY spectral dependence of CdSe quantum dots (QDs) is found, which suggests its common origin regardless the material of semiconductor QDs.
Permanent Link: http://hdl.handle.net/11104/0318260