Anisotropic carrier diffusion in single MAPbI3 grains correlates to their twin domains

Ilka M Hermes,Hans-Jürgen Butt,Stefan A L Weber,David S Ginger,Andreas Best,Sarah M Vorpahl,Markus Mezger,Leonard Winkelmann,Liam Collins,Julian Mars,Kaloian Koynov

doi:10.1039/d0ee01016b

Abstract

The anisotropic charge carrier diffusion coupled to ferroelastic twin domains in methylammonium lead iodide opens possibilities for further optimization of perovskite solar cells and optoelectronic devices via strain engineering and heat treatments.

Highlights

We were able to directly correlate an anisotropic charge carrier diffusion with the orientation of ferroelastic twin domains in isolated MAPbI3 grains
Introduction a Max Planck Institute forPolymer Research, Ackermannweg 10, 55128 Mainz, Germany
In agreement with the initial results, we consistently detected longer diffusion times for diffusion paths perpendicular than for those parallel to the domains. These results suggest that the origin for anisotropic charge carrier diffusion in MAPbI3 perovskite is directly related to the domain pattern resolved via piezoresponse force microscopy (PFM)

Summary

Introduction

We were able to directly correlate an anisotropic charge carrier diffusion with the orientation of ferroelastic twin domains in isolated MAPbI3 grains. To resolve the lateral distribution of carrier diffusion times in single MAPbI3 grains, we used spatial- and time-resolved PL microscopy: we measured time-resolved PL decays following picosecond excitation pulses in varying distances from the excitation, by moving the detection volume independently from the fixed excitation position over the grain (ESI,† Fig. S1).

Results

Conclusion