Sub-second Lifetime of Photocarriers in Hybrid Lead Halide Perovskite

Recently lead halide perovskite based solar cells have rapidly advanced and their power conversion efficiency (PCE) increased to 25.7%. The progress has been attributed to the super-long carriers' lifetime (tau) and long diffusion length (L-D) of the photocarriers, however it has been a challenge to precisely characterize and understand the super-long tau and L-D of photocarriers. Here, a MAPbI(3) single crystal exhibits four different tau which increase with L-D extending from nm scale to mm scale. The prior two lifetimes estimated by transient photoluminescence (TPL) spectra are in the range of ns which comes from the recombination of photocarriers in the tens of nm thick surface layer. In contrast, the third lifetime estimated by transient open-circuit voltage is hundreds of mu s, which is a result of the excess photocarriers diffusing hundreds of mu m to electrodes. Finally, the fourth lifetime estimated from the transient photoconductance is as long as sub-second since the low-density photocarriers under an electric field drift across the mm-scale high-quality single crystal. This study not only clarifies the physical mechanisms of four different lifetimes of photocarriers but also facilitates the design of novel electronics with the halide perovskite semiconductors.

Automated summary

This study investigates the four different lifetimes of photocarriers in MAPbI(3) single crystal, shedding light on the physical mechanisms and facilitating the design of novel electronics with halide perovskite semiconductors.