Efficient carrier separation and intriguing switching of bound charges in inorganic-organic lead halide solar cells

Abstract

We fabricated a mesoporous perovskite solar cell with a ∼14% conversion efficiency, and we investigated its beneficial grain boundary properties of the perovskite solar cells through the use of scanning probe microscopy. The CH<inf>3</inf>NH<inf>3</inf>Pb(I<inf>0.88</inf>,Br<inf>0.12</inf>)<inf>3</inf> showed a significant potential barrier bending at the grain boundary and induced passivation. The potential difference value in the x = 0.00 sample is ∼50 mV, and the distribution of the positive potential is lower than that of the x = 0.12 sample. We also investigated the polarization and hysteretic properties of the perovskite thin films by measuring the local piezoresponse. Specifically, the charged grain boundaries play a beneficial role in electron-hole depairing and in suppressing recombination in order to realize high-efficiency perovskite solar cells. © 2015 American Chemical Society.