Mg-Doped Nickel Oxide as Efficient Hole-Transport Layer for Perovskite Photodetectors

The use of additives in the transport layer can affect film formation, passivate the defects in the bulk or at the surface, and tune the direct bandgap, which promotes the performance of perovskite photodetectors. In this work, the incorporation of Mg into NiO anode interlayers which are used as hole transporting layers (HTLs) in organic–inorganic hybrid perovskite photodetectors is investigated. The device configuration is indium tin oxide (ITO)/NiO or Mg-doped NiO/CH3NH3PbI3/C60/bathocuproine (BCP)/Cu. Mg-doped NiO as the HTL for perovskite photodetectors improves the electrical conductivity and the crystallinity of perovskite thin films, which also helps promote energy level matching with the perovskite layer. These can greatly improve hole transport and extraction abilities as well as reduce carrier recombination. The performance of the perovskite photodetector is confirmed by analyzing the current density–voltage characteristics as well as dynamic and transient photocurrent response characteristics. The device with the Mg-doped NiO layer presents a high specific detectivity of 5.3 × 1013 jones and a large linear dynamic range of 124 dB, which is comparable to that of the commercial Si photodetectors (120 dB). The approach of Mg-doped NiO as HTLs paves a pathway to effectively facilitate the performance of perovskite photodetectors.