Abnormal Dynamic Reverse Bias Behavior and Variable Reverse Breakdown Voltage of ETL‐free Perovskite Solar Cells

Abstract

Perovskite solar cells (PSCs) have shown an impressive power conversion efficiency (PCE) of 26.1%, while their upcoming commercialization urgently needs to solve the stability problem. Among numerous stability issues of PSCs, little attention has been paid to reverse bias stability. When some cells of the module are shaded by irresistible factors, this will cause the current of the illuminated part to flow through the shaded cells as a reverse current and force them to be under reverse bias. Here, we distinguish the breakdown mechanism dominated by different reverse bias regions of a prototype ETL‐free p‐n junction PSCs. And it is confirmed that PSCs present a thought‐provoking dynamic reverse bias (DRB) behavior and variable reverse breakdown voltage (VRB), which is essentially distinct from classic solar cells. Specifically, VRB is significantly affected by voltage scan rate, range and direction, and illumination. The underlying mechanism was explained by drift‐diffusion modelling taking into account the electric field generated by directional ion migration. The latter can hinder the movement of charge carriers and cause the observed variable VRB and DRB behavior. Predictably, additional obstacles and challenges in the practical application of PSCs will be brought by variable VRB. The module design and bypass diode connection method of PSCs will need to be improved. Moreover, such a newfound DRB behavior can increase the complexity for establishing reliable and non‐destructive VRB measurement procedures of PSCs. So, the understanding of the dynamic process is crucial to establish a standard VRB measurement procedure and further promote the commercialization of PSCs.This article is protected by copyright. All rights reserved.

Multifunctional dual-interface layer enables efficient and stable inverted perovskite solar cells

“…It can be seen that optimizing the device structure helps to improve the reverse bias stability of the device, which is very helpful for future commercial components to cope with shading effects. 46,47 The improvement of the device bias stability may be due to the inhibition of ion migration by the interface layer. 48,49 Also, we tracked the normalization efficiency of three unencapsulated devices under dark conditions.…”