Revealing lattice and photocarrier dynamics of high-quality MAPbBr 3 single crystals by far infrared reflection and surface photovoltage spectroscopy

Jian Wang*, Elaheh Motaharifar, Lakshmi N.S. Murthy, Marissa Higgins, Diego Barrera, Trey B. Daunis, Yangzi Zheng, Anton V. Malko, Fernando Ely, Manuel Quevedo-Lopez, Mark Lee, Julia W.P. Hsu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

Hybrid organic-inorganic lead halide perovskite materials show great promise in a number of optoelectronic applications, including solar cells, light emitting diodes, and photodetectors. Understanding their intrinsic material properties is critical to enhancing device performance and enabling innovative material and device designs. Here, we study lattice dynamics using far-infrared (FIR) reflectance and photogenerated carrier dynamics using surface photovoltage (SPV) measurements on high-quality methylammonium lead bromide (MAPbBr 3 ) single crystals. FIR reflectance shows three coherent infrared-active phonon modes between 40 and 200 cm -1 that result in reststrahlen bands with much higher peak reflectance than has been previously reported. The phonon mode strength and damping are comparable to classical oxide perovskite single crystals. However, the effects of defects on photogenerated carrier recombination are still evident in SPV measurements. By performing SPV over different spectral ranges, we are able to separate the effects of surface and bulk defects on the recombination dynamics of photogenerated charge carriers. We further apply SPV measurements to obtain the minority carrier (electron) diffusion length for the MAPbBr 3 crystal. This study demonstrates that both FIR reflectance and SPV measurements provide useful information on the electromagnetic response properties of halide perovskite single crystals.

Original languageEnglish
Article number025706
JournalJournal of Applied Physics
Volume125
Issue number2
DOIs
StatePublished - 14 Jan 2019
Externally publishedYes

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© 2018 Author(s).

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