According to this report; Caffeine’s a boost not just for humans…:
Caffeine makes perovskite photovoltaics more stable, enhancing their commercial potential
Caffeine’s calming effect starts during the creation of perovskite crystals. “Without caffeine, the crystallization process will just take 2 seconds, but with caffeine it will take 1 to 2 minutes,” says Yang. The more deliberate growth process yields a perovskite material with larger grains of defect-free crystal.