Quantification of hot carrier thermalization in PbS colloidal quantum dots by power and temperature dependent photoluminescence spectroscopy

Wenkai Cao, Zewen Zhang, Rob Patterson, Yuan Lin, Xiaoming Wen, Binesh Puthen Veetil, Pengfei Zhang, Qiuyang Zhang, Santosh Shrestha, Gavin Conibeer, Shujuan Huang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

PbS QDs are studied as attractive candidates to be applied as hot carrier solar cell absorbers. The thermalization properties of PbS QDs are investigated with power and temperature dependent continuous wave photoluminescence (CWPL). Non-equilibrium hot carrier populations are generated by high energy laser excitation, the thermalization coefficient Q is estimated from the incident power dependent carrier temperature. A non-equilibrium hot carrier population 200 K above the lattice temperature is detected at mild illumination intensity. A higher energy carrier population and an increasing Q value are observed with rising lattice temperatures. State filling effects are proposed as a possible cause of the generation of the non-equilibrium hot carrier population and an enhanced electron-phonon coupling strength is suggested to account for the faster carrier cooling rate observed in closely packed Langmuir-Blodgett monolayer films. A thermalization coefficient, Q, as low as 6.55 W K-1 cm-2 was found for the drop cast sample and suggests that PbS QDs are good candidates for practical hot carrier absorbers.

Original languageEnglish
Pages (from-to)90846-90855
Number of pages10
JournalRSC Advances
Volume6
Issue number93
DOIs
Publication statusPublished - 2016
Externally publishedYes

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