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

Abstract

The\nuse of additives in the transport layer can affect film formation,\npassivate the defects in the bulk or at the surface, and tune the\ndirect bandgap, which promotes the performance of perovskite photodetectors.\nIn this work, the incorporation of Mg into NiO anode interlayers which\nare used as hole transporting layers (HTLs) in organic–inorganic\nhybrid perovskite photodetectors is investigated. The device configuration\nis indium tin oxide (ITO)/NiO or Mg-doped NiO/CH₃NH₃PbI₃/C₆₀/bathocuproine (BCP)/Cu. Mg-doped\nNiO as the HTL for perovskite photodetectors improves the electrical\nconductivity and the crystallinity of perovskite thin films, which\nalso helps promote energy level matching with the perovskite layer.\nThese can greatly improve hole transport and extraction abilities\nas well as reduce carrier recombination. The performance of the perovskite\nphotodetector is confirmed by analyzing the current density–voltage\ncharacteristics as well as dynamic and transient photocurrent response\ncharacteristics. The device with the Mg-doped NiO layer presents a\nhigh specific detectivity of 5.3 × 10¹³ jones and\na large linear dynamic range of 124 dB, which is comparable to that\nof the commercial Si photodetectors (120 dB). The approach of Mg-doped\nNiO as HTLs paves a pathway to effectively facilitate the performance\nof perovskite photodetectors.