UCLA researchers in the department of Materials Science & Engineering have discovered a novel Lewis base additive that decreases heterogeneity in perovskite thin films.
Over the last decade, the certified power conversion efficiency (PCE) of perovskite solar cells has increased to 22.1%, establishing perovskites as viable alternatives to the widely used silicon solar cell. Further PCE improvement can be achieved by reducing the microscale heterogeneity of the films, but conventional techniques to improve crystal growth require additional steps or processing time. Therefore, novel scalable and efficient strategies that improve microscale properties will be important to further enhance the photovoltaic properties of perovskite solar cells.
Researchers led by Professor Yang Yang have developed a novel strategy to decrease heterogeneity in perovskite thin films by adding novel Lewis bases. The additives have been shown to improve microscale properties by enhancing crystallinity and decreasing grain boundaries and related defects. The bases can be easily added to the solution before further processing and do not need to be removed after crystal growth. Perovskite devices using this method demonstrated a 10% increase in PCE and the best performing device achieved a PCE of 18.6%.
Devices containing Lewis bases have been fabricated and the optoelectronic properties have been tested. Devices containing Lewis base additives display 10% increase in power conversion efficiency compared to devices without the additives.
Perovskite solar cell; solution processable; crystal growth; solar cells; photovoltaic device; opto-electronics