Passivation of Iodine Vacancies in Perovskite Photodetectors by Oxygen Functional Groups in the Main and Side Chains of Alcohol Polymers

Metal halide perovskites are ideal materials for optoelectronic devices. However, the optoelectronic performance and environmental stability of perovskite photodetectors (PPDs) are significantly affected by defects in perovskites, such as iodine vacancies. In this work, polymers with oxygen functional groups in the main and side chains are employed as the defect passivating agents targeting iodine vacancies in CH3NH3PbI3 (MAPbI3). The oxygen functional groups in the side chains have stronger interactions with MAPbI3 than those of the main chains. This interaction helps to reduce the iodine vacancy, increase recombination resistance, and suppress dark current. Consequently, the responsivity and detectivity of PPDs are enhanced, achieving 0.147 A/W and 1.87 × 1011 Jones, respectively, while also enhancing environmental stability of PPDs. This work provides valuable references for selecting polymer passivation molecules that address defects in perovskite thin films.