Rapid Layer-Specific Annealing Enabled by Ultraviolet LED with Estimation of Crystallization Energy for High-Performance Perovskite Solar Cells

A rapid layer-specific annealing on perovskite active layer enabled by ultraviolet (UV) light-emitting diode (LED) is demonstrated and efficiency close to 19% is achieved in a simple planar inverted structure ITO/PEDOT:PSS/MAPbI(3)/PC71BM/Al without any device engineering. These results demonstrate that if the UV dosage is well managed, UV light is capable of annealing perovskite into high-quality film rather than simply damaging it. Different in principle from other photonic treatment techniques that can heat up and damage underlying films, the UV-LED-annealing method enables layer-specific annealing because LED light source is able to provide a specific UV wavelength for maximum light absorption of target film. Moreover, the layer-specific photonic treatment allows accurate estimation of the crystallization energy required to form perovskite film at device quality level.