Abstract:
For the first time, room temperature heating free growth and crystallization of perovskite films in ambient air
without the use of thermal annealing is reported. Highly efficient perovskite nanorod-based solar cells were
made using ITO/PEDOT:PSS/CH3NH3PbI3 nanorods/PC60BM/rhodamine/Ag. All the layers except
PEDOT:PSS were processed at room temperature thereby eliminating the need for thermal treatment.
Perovskite films were spin coated inside a N2 filled glovebox and immediately were taken outside in air
having 40% relative humidity (RH). Exposure to humid air was observed to promote the crystallization
process in perovskite films even at room temperature. Perovskite films kept for 5 hours in ambient air
showed nanorod-like morphology having high crystallinity, with devices exhibiting the highest PCE of
16.83%, which is much higher than the PCE of 11.94% for traditional thermally annealed perovskite film
based devices. It was concluded that moisture plays an important role in room temperature
crystallization of pure perovskite nanorods, showing improved optical and charge transport properties,
which resulted in high performance solar cells.
