Iodine-trapping strategy for light-heat stable inverted perovskite solar cells under ISOS protocols

It's a big challenge for perovskite solar cells (PSCs) to realize operational stability simultaneously under light and heat conditions according to the International Summit on Organic Photovoltaic Stability (ISOS). One key reason lies in that light-induced iodine in perovskite will escape under heat conditions, accelerating perovskite degradation and generating large Pb0 defects. Here, an iodine-trapping strategy is proposed to fabricate operationally stable PSCs through introducing an iodine trapper of beta-cyclodextrin (beta-CD). beta-CD can trap the iodine generated in perovskite and inhibit their escape owing to its bowl structure. Besides, the trapped iodine can react with and eliminate Pb0 in perovskite films, further improving device stability. The resulting PSCs retain 91.8% of the highest efficiency under ISOS-L-1 after MPP tracking for 1000 hours at 25 degrees C. Importantly, PSCs with beta-CD meet the requirements of the ISOS-L-2 protocol, retaining 81.2% (88.5% of initial value) of the highest efficiency after MPP tracking for 300 hours at 85 degrees C. An iodine trapping strategy is proposed to inhibit the iodine escaping in perovskite and realize light-heat stable perovskite solar cells, retaining over 80% of initial efficiency after maximum power point tracking for 300 h at 85 degrees C.

Automated summary

The study proposes an iodine trapping strategy to inhibit the escape of iodine in perovskite and achieve operationally stable perovskite solar cells. This method can not only prevent the escape of iodine but also eliminate Pb0 defects in perovskite, improving the stability of the devices.