Photogeneration Quantum Yield and Character of Free Charges and Excitons in PbSe Nanorods

Journal Article (2020)
Authors

A. Kulkarni (TU Delft - ChemE/Opto-electronic Materials)

WH Evers (BN/Technici en Analisten)

Thomas P. Van Waas (Student TU Delft)

L. D.A. Siebbeles (TU Delft - ChemE/Opto-electronic Materials)

Research Group
BN/Technici en Analisten
Copyright
© 2020 A. Kulkarni, W.H. Evers, Thomas P. Van Waas, L.D.A. Siebbeles
To reference this document use:
https://doi.org/10.1021/acs.jpcc.0c00541
More Info
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Publication Year
2020
Language
English
Copyright
© 2020 A. Kulkarni, W.H. Evers, Thomas P. Van Waas, L.D.A. Siebbeles
Research Group
BN/Technici en Analisten
Issue number
13
Volume number
124
Pages (from-to)
7550-7557
DOI:
https://doi.org/10.1021/acs.jpcc.0c00541
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Abstract

Lead selenide (PbSe) nanorods are of interest for applications in infrared LEDs, lasers, and photovoltaics due to the possibility of tuning their band gap from the far- to the near-infrared by decreasing their radius. We study the photogeneration quantum yield and properties of free charges and excitons in PbSe nanorods using a combination of time-resolved transient optical absorption and terahertz spectroscopy. Photoexcitation predominantly leads to the formation of excitons and to a smaller extent to free mobile charges. Theoretical analysis of the exprimental data yields an exciton polarizability of 10-35 C m2 V-1. The sum of the mobilities of a free electron and a hole is found to be close to 100 cm2 V-1 s-1. The high quantum yield of excitons makes PbSe nanorods of interest as a gain material in near-infrared LEDs or lasers. To use PbSe nanorods in photovoltaics, heterojunctions must be realized so that excitons can dissociate into free charges.