Implications of light‑soaking–induced photobrightening for actual device performance

Ascertain the implications of light soaking–induced photobrightening, observed during voltage‑dependent photoluminescence mapping of perovskite solar cells, for actual device performance metrics such as short‑circuit current, fill factor, and power conversion efficiency, given that this effect produces a vertical offset between forward and reverse optical current–voltage scans that is not observed in electrical current–voltage measurements.

Background

In the study, the authors employ voltage‑dependent photoluminescence (PL) imaging to extract local optical current–voltage characteristics concurrently with electrical JV measurements on perovskite solar cells. During these measurements, some samples exhibit light soaking that causes photobrightening, which shifts the forward optical scan upward, creating an apparent hysteresis in optical short‑circuit current not mirrored in electrical JV data.

The authors explicitly note that the consequences of this light‑soaking‑induced photobrightening for real device operation are not yet established. Resolving this uncertainty is important to interpret operando optical measurements correctly and to understand whether such optical hysteresis reflects genuine performance changes or measurement-induced artifacts.