High efficiency perovskite photodetectors with NiO_x hole transport layer enabled by F4-TCNQ: BCF buried interface layer

Interface engineering is widely used to enhance the efficiency and stability of photodetectors (PDs). Although fluorine-containing materials are ideal for interface modification, they are seldom used at the NiO_x/perovskite interface. This paper reports on the use of Tris(pentafluorophenyl)borane (BCF) and 2,3,5,6-tetrafluoro-7,7,8,8- tetracyanoquinodimethane (F4-TCNQ)-modified NiO_x HTL to achieve high-efficiency and high-stability PDs. This study shows that BCF and F4-TCNQ interact to provide better doping ability, form Lewis adducts with Pb²⁺, and enhance the crystallinity of their perovskites. Interaction with nickel oxide optimizes the Ni³⁺/Ni²⁺ ratio, thus improving conductivity and charge transport capability. The F4-TCNQ:BCF modification effectively reduces interface defects, improves carrier mobility, and enhances both the performance and stability of PDs in ambient air. The detector achieves a maximum EQE value of 89.4%, a dark current density of 1.51 × 10⁻¹⁰A cm⁻², a detectivity of 6.33 × 10¹³ Jones, and a LDR of 133.4 dB. Additionally, the interfacially modified device maintains over 90% of its initial performance after one month of storage in ambient air. Our results highlight the importance of F4-TCNQ:BCF interface modification and provide a reference for the further research and development of perovskite devices.