Theory of Photoluminescence Spectral Line Shapes of Semiconductor Nanocrystals

• DOI: 10.1021/acs.jpclett.3c01630
• Publication Date: 2023-08-08T17:31:28Z
• Authors: Kailai Lin; Dipti Jasrasaria; Jason J. Yoo; Moungi Bawendi; Hendrik Utzat; Eran Rabani
• Keywords: Line (geometry)

Single-molecule photoluminescence (PL) spectroscopy of semiconductor nanocrystals (NCs) reveals the nature exciton-phonon interactions in NCs. Understanding narrow line shapes at low temperatures and significant broadening as temperature increases remains an open problem. Here, we develop atomistic model to describe PL spectrum NCs, accounting for excitonic effects, phonon dispersion relations, couplings. We use single-molecule measurements on CdSe/CdS core-shell NCs from T=4 T=290K validate our find that slightly-asymmetric main peak is comprised a zero-phonon (ZPL) several acoustic sidebands. Furthermore, identify distinct CdSe optical modes give rise As increases, spectral width shows stronger dependence temperature, which demonstrated be correlated with frequency shifts mode-mixing, reflected higher-order couplings (Duschinsky rotations). also core size shell thickness provide strategies design linewidths elevated temperatures.