Rapid assessment of photovoltaic activity of perovskite solar cells by photoluminescence spectroscopy

[Display omitted] •Photoluminescence as a versatile tool to assess the photovoltaic activity of PSCs.•Detection of unexpected peak at 738 nm in photoluminescence for perovskites.•Significant reduction in efficiency of PSCs with the unexpected peak at 738 nm.•Conventional characterization do not unveil any major difference in perovskites.•Photoluminescence can effectively shorten the optimization process for perovskites. Herein, we report a surprising yet noteworthy aspect that despite the perovskite absorbers being processed under similar conditions, the perovskite solar cells (PSC) exhibited radically different photovoltaic performance. Analysis of these absorbers unveil similar morphology, crystallinity and absorption properties. When steady-state photoluminescence (PL) is performed, a set of absorbers possesses an unexpected peak at 738 nm alongside the conventional peak around 770 nm. The absorbers exhibiting this unexpected peak have demonstrated significantly reduced photovoltaic activity compared to those without the peak. The origin of this phenomenon can be traced to the aged methyl ammonium iodide precursor. The study puts forward an important insight that PL analysis may provide additional information which enables rapid assessment of photoactivity of PSC – even before fabricating and testing the complete solar cell.