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Ensemble Effects in the Temperature‐Dependent Photoluminescence of Silicon Nanocrystals
Author(s) -
Jakob Matthias,
Javadi Morteza,
Veinot Jonathan G. C.,
Meldrum Al,
Kartouzian Aras,
Heiz Ulrich
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201804986
Subject(s) - photoluminescence , materials science , nanocrystal , silicon , condensed matter physics , engineering physics , nanotechnology , chemical physics , optoelectronics , chemistry , physics
In this work the temperature‐dependent photoluminescence of alkyl‐capped silicon nanocrystals with mean diameters of between 3 and 9 nm has been investigated. The nanocrystals were characterized extensively by FTIR, TEM, powder XRD, and X‐ray photoelectron spectroscopy prior to low‐temperature and time‐resolved photoluminescence spectroscopy experiments. The photoluminescence (PL) properties were evaluated in the temperature range of 41–300 K. We found that the well‐known temperature‐dependent blueshift of the PL maximum decreases with increasing nanocrystal diameter and eventually becomes a redshift for nanocrystal diameters larger than 6 nm. This implies that the observed shifts cannot be explained solely by band‐gap widening, as is commonly assumed. We propose that the luminescence of drop‐cast silicon nanocrystals is affected by particle ensemble effects, which can explain the otherwise surprising temperature dependence of the luminescence peak.