Hot Carrier and Surface Recombination Dynamics in Layered InSe Crystals

Chengmei Zhong, Vinod K. Sangwan, Joohoon Kang, Jan Luxa, Zdeněk Sofer, Mark C. Hersam*, Emily A. Weiss

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Layered indium selenide (InSe) is a van der Waals solid that has emerged as a promising material for high-performance ultrathin solar cells. The optoelectronic parameters that are critical to photoconversion efficiencies, such as hot carrier lifetime and surface recombination velocity, are however largely unexplored in InSe. Here, these key photophysical properties of layered InSe are measured with femtosecond transient reflection spectroscopy. The hot carrier cooling process is found to occur through phonon scattering. The surface recombination velocity and ambipolar diffusion coefficient are extracted from fits to the pump energy-dependent transient reflection kinetics using a free carrier diffusion model. The extracted surface recombination velocity is approximately an order of magnitude larger than that for methylammonium lead-iodide perovskites, suggesting that surface recombination is a principal source of photocarrier loss in InSe. The extracted ambipolar diffusion coefficient is consistent with previously reported values of InSe carrier mobility.

Original languageEnglish (US)
Pages (from-to)493-499
Number of pages7
JournalJournal of Physical Chemistry Letters
Issue number3
StatePublished - Feb 7 2019

ASJC Scopus subject areas

  • Materials Science(all)
  • Physical and Theoretical Chemistry


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