Tiny pinholes can lead to device failure in perovskite solar cells

A team of scientists in the United States has studied how a perovskite solar cell degrades when under reverse bias conditions. Their research is presented in the paper “How non-ohmic contact-layer diodes in perovskite pinholes affect abrupt low-voltage reverse-bias breakdown and destruction of solar cells,” available in the journal Joule.

The paper says lead-halide perovskites have gained traction as commercially viable solar cell materials but are still highly susceptible to abrupt breakdown and permanent degradation when subject to modest reverse bias.

The researchers used electrical measurements, electron microscopy and optical and thermal imaging to investigate abrupt breakdown and hot spotting under low reverse potentials. They deployed a before, during and after strategy to compare pictures of devices that had been exposed to reverse bias.

High-resolution images showed that microscopic pinholes in the perovskite layer cause rapid, destructive breakdown under reverse bias, despite minimally reducing power conversion efficiencies.