Revealing Charge Carrier Mobility and Defect Densities in Metal Halide Perovskites via Space-Charge-Limited Current Measurements

Space-charge-limited current (SCLC) measurements have been widely used to study the charge carrier mobility and trap density in semiconductors. However, their applicability to metal halide perovskites is not straightforward, due to the mixed ionic and electronic nature of these materials. Here, we discuss the pitfalls of SCLC for perovskite semiconductors, and especially the effect of mobile ions. We show, using driftdiffusion (DD) simulations, that the ions strongly affect the measurement and that the usual analysis and interpretation of SCLC need to be refined. We highlight that the trap density and mobility cannot be directly quantified using classical methods. We discuss the advantages of pulsed SCLC for obtaining reliable data with minimal influence of the ionic motion. We then show that fitting the pulsed SCLC with DD modeling is a reliable method for extracting mobility, trap, and ion densities simultaneously. As a proof of concept, we obtain a trap density of 1.3 x 10(13) cm(-3), an ion density of 1.1 x 10(13) cm(-3), and a mobility of 13 cm(2) V-1 s(-1) for a MAPbBr(3) single crystal.

Automated summary

Space-charge-limited current (SCLC) measurements are widely used to study charge carrier mobility and trap density in semiconductors, but their application to metal halide perovskites is complicated by the mixed ionic and electronic nature of these materials. The presence of mobile ions strongly affects the measurements, requiring a refined analysis and interpretation of SCLC. Pulsed SCLC, combined with drift-diffusion simulations, offers a reliable method for simultaneously extracting mobility, trap, and ion densities in perovskite semiconductors.