Low dark current and high-performance hybrid perovskite photodetectors with a PBDB-T:IHIC ultrathin passivation layer

In this Letter, the reduction of undesired high dark current caused by defect states in solution-processed perovskite for photodetectors is realized with the introduction of an ultrathin buffer layer of PBDB-T:IHIC bulk heterojunction (BHJ). By controlling the concentration of BHJ precisely during a solution process, a low dark current density (J_d) of 1.01×10^-4mA/cm² and a high specific detectivity (D^∗) of 2.61×10¹²Jones were achieved. It was found that low J_d is attributed to the passivation effect of BHJ on defect states, where BHJ acts as a Lewis base and interacts with unbonded Pb²⁺ in perovskite. This Letter demonstrates that the application of ultrathin organic BHJ has significant potential for the manufacturing of high-performance optoelectronic devices.