Van der Waals heterojunction devices based on organohalide perovskites and two-dimensional materials

摘要

The recently emerged organohalide perovskites (e.g., CH3NH3PbI3) have drawnintense attention for high efficiency solar cells. However, with a considerablesolubility in many solvents, these perovskites are not typically compatiblewith conventional lithography processes for more complicated devicefabrications that are important for both fundamental studies and technologicalapplications. Here we report the creation of novel heterojunction devices basedon perovskites and two-dimensional (2D) crystals by taking advantage of thelayered characteristic of lead iodide (PbI2) and vapor phase intercalation. Weshow a graphene/perovskite/graphene vertical stack can deliver a highestphotoresponsivity of ~950 A/W and photoconductive gain of ~2200, and agraphene/WSe2/perovskite/graphene heterojunction can display a high on/offratio (~10^6) transistor behavior with distinct gate-tunable diodecharacteristics and open-circuit voltages. Such unique perovskite-2Dheterostructures have significant potential for future optoelectronic researchand can enable broad possibilities with compositional tunability oforganohalide perovskites and the versatility offered by diverse 2D materials.