Suppressing non-radiative recombination in metal halide perovskite solar cells by synergistic effect of ferroelasticity

The origin of low non-radiative recombination in perovskites was not well-understood. Here, authors apply electric field to manipulate ferroelastic lattice deformation to study non-radiative recombination and strain in twinning tetragonal phase, achieving an increased open-circuit voltage to 1.26 V. The low fraction of non-radiative recombination established the foundation of metal halide perovskite solar cells. However, the origin of low non-radiative recombination in metal halide perovskite materials is still not well-understood. Herein, we find that the non-radiative recombination in twinning-tetragonal phase methylammonium lead halide (MAPbI(x)Cl(3-x)) is apparently suppressed by applying an electric field, which leads to a remarkable increase of the open-circuit voltage from 1.12 V to 1.26 V. Possible effects of ionic migration and light soaking on the open-circuit voltage enhancement are excluded experimentally by control experiments. Microscopic and macroscopic characterizations reveal an excellent correlation between the ferroelastic lattice deformation and the suppression of non-radiative recombination. The calculation result suggests the existence of lattice polarization in self-stabilizable deformed domain walls, indicating the charge separation that facilitated by lattice polarization is accountable for the suppressed non-radiative recombination. This work provides an understanding of the excellent performance of metal halide perovskite solar cells.

Automated summary

The authors manipulated ferroelastic lattice deformation using electric fields to study non-radiative recombination and strain in twinning tetragonal phase, leading to an increased open-circuit voltage of 1.26 V. This study provides insights into the low non-radiative recombination in metal halide perovskite solar cells.