High-Efficiency and Stable Perovskite Photodetectors with an F4-TCNQ-Modified Interface of NiOx and Perovskite Layers

Nickel oxide (NiOx), a typical p-type semiconductor, is emerging as the most promising hole transport layer material. However, the inferior interfacial contact of the NiOx/perovskite interface has limited the improvement of the performance of photodetectors (PDs). In this work, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) is introduced to modify the NiOx/perovskite interface to prepare high-performance PDs. This study shows that the F4-TCNQ layer interacts with the NiOx/perovskite layers. It can increase the Ni3+/Ni2+ ratio and then enhance the hole extraction and charge carrier mobility; on the contrary, it can form a new Lewis adduct and passivate the undercoordinated Pb2+ ions. Furthermore, with the F4-TCNQ modification, the perovskite film exhibits good thermal stability and photostability. The PDs demonstrate excellent photoelectric properties and long-term stability in the atmosphere. This finding provides a simple and efficient way to further develop the NiOx/perovskite interface.