The superior crystallinity of the PVSK films containing caffeine boast reduced defect densities and better vertical charge transport, allowing for a champion PCE as high as 20.25% (compared to 17% for films without caffeine), he tells Physics World. The caffeine-containing devices are also thermally stable for over 1300 hours at 85°C (compared to just 150 hours for films without caffeine).https://physicsworld.com/a/caffeine-boosts-perovskite-solar-cells/
The idea of adding caffeine to these materials started out as a joke over morning coffee, recalls team member Jingjing Xue. “One day, as we were discussing perovskite solar cells, our colleague Rui Wang said: ‘if we need coffee to boost our energy, then what about perovskites?’”