Incorporating deep electron traps into perovskite devices: towards high efficiency solar cells and fast photodetectors

Abstract

Compared with the charge recombination loss from the unfavorable defects of the perovskite layer, the inferior charge transport characteristics of the interlayers deteriorate the efficiency in solar cells and slow the response speed in photodetectors. Here, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) is incorporated into a 4,4′,4′′-tris(3-methylphenylphenylamino)triphenylamine (m-MTDATA) layer to facilitate hole transport by providing deep electron traps. The increased work function and enlarged hole mobility of the composite hole transport layer are beneficial for the photoelectric conversion process of the perovskite photovoltaic devices. Consequently, an enhanced efficiency of 18.35% is achieved for the perovskite solar cells and a shortened decay time of 39.8 ns is obtained for the perovskite photodetectors. This work reveals the limitation of the transport layers on the perovskite solar cells and photodetectors, and provides an effective method to obtain high efficiency solar cells and fast photodetectors.