Optical characterization of voltage-accelerated degradation in CH_3NH_3PbI_3 perovskite solar cells

Abstract

We investigate the performance degradation mechanism of CH₃NH₃PbI₃ perovskite solar cells under bias voltage in air and nitrogen atmospheres using photoluminescence and electroluminescence techniques. When applying forward bias, the power conversion efficiency of the solar cells decreased significantly in air, but showed no degradation in nitrogen atmosphere. Time-resolved photoluminescence measurements on these devices revealed that the application of forward bias in air accelerates the generation of non-radiative recombination centers in the perovskite layer buried in the device. We found a negative correlation between the electroluminescence intensity and the injected current intensity in air. The irreversible change of the perovskite grain surface in air initiates the degradation of the perovskite solar cells.

Diagnosis of Perovskite Solar Cells Through Absolute Electroluminescence-Efficiency Measurements

“…Nevertheless, when applying high current densities, y LED ext gradually decreased. Similar behaviors were observed previously in PSCs [27,[29][30][31], and two possible origins with high carrier density are suggested: (1) Generation of non-radiative recombination centers [29] and (2) migration of ions induced generation of trap-type vacancy defects in the perovskite layer [30], which may be responsible for the observed degradation of the EL efficiency.…”

Device Physics of Hybrid Perovskite Solar cells: Theory and Experiment

“…[68] Copyright 2014, American Chemical Adapted with permission. [71] Copyright 2017, American Chemical Society. (d) Evolution of normalized PL intensity under continuous excitation for three different devices of distinct perovskite and fabrication procedure.…”

ASnX3—Better than Pb‐based Perovskite

“…[ 19–40,42 ] Other factors like an energy‐level mismatch between the tin based perovskite and the hole transporting materials may have a role, too. [ 43–49 ]…”