Mechanism and effect of γ-butyrolactone solvent vapor post-annealing on the performance of a mesoporous perovskite solar cell.

Jun Luo,Zhi Sheng Yang,Ren Zheng Qiu,Qi Feng Zhang,Yan Xiang Wang

doi:10.1039/c7ra10695e

Abstract

In this paper, γ-butyrolactone (GBL) solvent vapor post-annealing (SVPA) on CH3NH3PbI3 thin films is reported, aiming to improve the complete transformation of PbI2 and increase the grain size of the CH3NH3PbI3 crystal, thus boosting the performance of mesoporous CH3NH3PbI3 perovskite solar cells (PSCs). The influence of GBL SVPA on the microstructure of perovskite layers and performance of PSCs was studied. The short circuit current density (Jsc) of the devices significantly increased, yielding a high efficiency of 16.58%, which was 27.05% higher than that of thermally annealed films. A model was derived to explain the effect of GBL SVPA on PSCs. The perovskite films prepared by this method present several advantages such as complete transformation of PbI2 to CH3NH3PbI3, high crystallinity, large grain size, and fewer grain boundaries than those prepared without GBL SVPA. This improvement is beneficial for charge dissociation and transport in hybrid photovoltaic devices.

Highlights

In recent years, organometal halide perovskite solar cells (PSCs), which are considered to be the most promising nextgeneration solar cells, have been extensively investigated.[1,2] In addition to their intense broadband absorption,[3] this type of PSC possesses small exciton binding energies,[4,5] long charge carrier diffusion lengths (100–1000 nm) and lifetimes ($100 ns),[6] good ambipolar charge mobilities, and low cost.[7]
The perovskite films prepared by this method present several advantages such as complete transformation of PbI2 to CH3NH3PbI3, high crystallinity, large grain size, and fewer grain boundaries than those prepared without GBL solvent vapor post-annealing (SVPA)
We investigated the effect of GBL solvent vapor post-annealing on the characteristics of perovskite lms and performances of the corresponding PSCs

Summary

Introduction

Organometal halide perovskite solar cells (PSCs), which are considered to be the most promising nextgeneration solar cells, have been extensively investigated.[1,2] In addition to their intense broadband absorption,[3] this type of PSC possesses small exciton binding energies (around 50 meV at room temperature),[4,5] long charge carrier diffusion lengths (100–1000 nm) and lifetimes ($100 ns),[6] good ambipolar charge mobilities, and low cost.[7]. Mechanism and effect of g-butyrolactone solvent vapor post-annealing on the performance of a mesoporous perovskite solar cell G-butyrolactone (GBL) solvent vapor post-annealing (SVPA) on CH3NH3PbI3 thin films is reported, aiming to improve the complete transformation of PbI2 and increase the grain size of the CH3NH3PbI3 crystal, boosting the performance of mesoporous CH3NH3PbI3 perovskite solar cells (PSCs).

Results

Conclusion