Power-dependent photoluminescence decay kinetics of silicon nanocrystals under continuous and pulsed excitation

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F20%3A10420714" target="_blank" >RIV/00216208:11320/20:10420714 - isvavai.cz</a>

Result on the web

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=W~3W_Q38qj" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=W~3W_Q38qj</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/c9fd00100j" target="_blank" >10.1039/c9fd00100j</a>

Result language

angličtina

Original language name

Power-dependent photoluminescence decay kinetics of silicon nanocrystals under continuous and pulsed excitation

Original language description

Power-dependent photoluminescence (PL) decay kinetics of silicon nanocrystals (Si NCs) in solid and liquid samples were studied under cw and pulsed excitation. The lifetime distribution and, consequently the measured PL kinetics are shown to depend on the excitation pulse duration until it is not sufficiently short (pulsed limit) or long (cw limit). These two excitation limits, however, are proven to excite different distributions of lifetime components and cannot be directly compared. We derive and experimentally confirm the equality of lifetimes averaged over amplitude and intensity for cw and pulsed excitation, accordingly. The absorption cross section (ACS) of Si NCs in solid and liquid samples is assessed and compared by two approaches under cw-excitation based on the treatment of power-modulated PL kinetics or PL amplitude saturation curves under low and moderate excitation powers, respectively. The discrepancy in extracted ACS values as well as the long-debated phenomena of incomplete PL saturation of matrix-embedded Si NCs is explained by a proposed model that is based on saturation of various components in an ensemble distribution at different excitation powers. The model finally allows us to explain the mystery of average decay lifetime dependence on excitation power in the non-linear power regime. By varying the excitation from cw to pulsed, we showed the reduction of average decay lifetime in the later case and attribute this to the increased relative PL contribution of fast lifetime components that results in at least one order of magnitude lower ACS values. Finally, exciting the solid sample with very high excitation powers, we detected a PL intensity decrease region that allowed us to extract the Auger lifetime which is about 170 ns.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10403 - Physical chemistry

Project

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Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2020

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Faraday Discussions

ISSN

1359-6640

e-ISSN

—

Volume of the periodical

222

Issue of the periodical within the volume

1st November 2019

Country of publishing house

GB - UNITED KINGDOM

Number of pages

20

Pages from-to

274-293

UT code for WoS article

000547895100017

EID of the result in the Scopus database

2-s2.0-85087094895