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

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.

Topics

• density
• perovskite
• single crystal
• mobility