Contactless measurements of photocarrier transport properties in perovskite single crystals

Xiwen Gong,Edward H Sargent,Makhsud I Saidaminov,Shana O Kelley,Oleksandr Voznyy,Grant Walters,Randy Sabatini,Chih-Shan Tan,Andrew Proppe,Ziru Huang,Golam Bappi

doi:10.1038/s41467-019-09538-7

Xiwen Gong, Edward H Sargent + Show 9 more

Open Access

https://doi.org/10.1038/s41467-019-09538-7

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Journal: Nature Communications	Publication Date: Apr 8, 2019
Citations: 54	License type: open-access

Affiliation: University of Toronto

Abstract

The remarkable properties of metal halide perovskites arising from their impressive charge carrier diffusion lengths have led to rapid advances in solution-processed optoelectronics. Unfortunately, diffusion lengths reported in perovskite single crystals have ranged widely – from 3 μm to 3 mm – for ostensibly similar materials. Here we report a contactless method to measure the carrier mobility and further extract the diffusion length: our approach avoids both the effects of contact resistance and those of high electric field. We vary the density of quenchers – epitaxially included within perovskite single crystals – and report the dependence of excited state lifetime in the perovskite on inter-quencher spacing. Our results are repeatable and self-consistent (i.e. they agree on diffusion length for many different quencher concentrations) to within ± 6%. Using this method, we obtain a diffusion length in metal-halide perovskites of 2.6 μm ± 0.1 μm.

Highlights

The remarkable properties of metal halide perovskites arising from their impressive charge carrier diffusion lengths have led to rapid advances in solution-processed optoelectronics
Thin film solar cells employing metal-halide perovskites have achieved an exceptional 23.7% certified power conversion efficiency (PCE)[1]
Shi et al reported Ld using mobility measured from electrical methods such as time-of-flight (TOF) transient photocurrent and Hall effect measurement[5]; when they combined the drift mobility with the photocarrier lifetime obtained from transient photoluminescence, the authors estimated the diffusion length of MAPbBr3 perovskite single crystal to reside in the range between 3 to 17 μm

Summary

Introduction

The remarkable properties of metal halide perovskites arising from their impressive charge carrier diffusion lengths have led to rapid advances in solution-processed optoelectronics. Shi et al reported Ld using mobility measured from electrical methods such as time-of-flight (TOF) transient photocurrent and Hall effect measurement[5]; when they combined the drift mobility with the photocarrier lifetime obtained from transient photoluminescence, the authors estimated the diffusion length of MAPbBr3 perovskite single crystal to reside in the range between 3 to 17 μm. We pursued the development of a method to measure diffusion lengths of perovskite single crystal directly and straightforwardly.

Results

Conclusion