Synergistically enhanced wide spectrum photodetection of a heterogeneous trilayer CsPbI3/PbS/ZnO architecture

Abstract

Mono-component photodetectors are usually limited by the narrow material absorption range and the easy recombination of photogenerated electrons and holes, so they cannot play a prominent role in high-performance wide-spectrum photodetection. Therefore, using engineered heterostructures to extend the absorption range, effectively separate the photogenerated electrons and holes, reduce the recombination, and improve the transport of photogenerated carriers is the optimal method to improve the photodetection performance. In this work, heterogeneous trilayer CsPbI₃/PbS/ZnO photodetectors were fabricated by a low-cost solution method. The CsPbI₃/PbS/ZnO architecture has the mutual complementation and enhancement advantages of the materials, the synergy between the two heterointerfaces promotes the efficient separation of carriers and inhibits back-flow and recombination, and ZnO and CsPbI₃ are used as separate transport layers of electrons and holes, respectively. The photodetectors based on the CsPbI₃/PbS/ZnO architecture achieved a wide spectrum photodetection of 300–1100 nm. Under 405 nm incident light, the CsPbI₃/PbS/ZnO photodetectors achieved a high responsivity of 280 mA W⁻¹, specific detectivity of 1.61 × 10¹¹ Jones, external quantum efficiency of 85% and fast rise/fall time of 64/63 ms. In addition, the CsPbI₃/PbS/ZnO architecture exhibits good mechanical flexibility after 500 folding cycles. The results demonstrate that the heterogeneous trilayer CsPbI₃/PbS/ZnO architecture is a promising candidate for flexible broadband photodetection.