Fully-printed, flexible cesium-doped triple cation perovskite photodetector

Abstract Organic–inorganic hybrid perovskite photodetectors show great promising applications in low-cost portable and wearable electronics. Herein, fully-printed, flexible cesium (Cs)-doped triple cation perovskite photodetector with good reliability and stability is achieved via a combination of roll-to-roll (R2R) micro-gravure printing, R2R slot-die coating and blade-coating, in which high-quality perovskite film is fabricated by two-step solution process on polyethylene terephthalate (PET) under ambient condition. As a result, the photodetector exhibits a broad photoresponse region from ultraviolet (UV) to near-infrared (NIR), a high responsivity (R) value of 1.62 A W−1, an excellent Ilight/Idark ratio as high as 1.83 × 104 and a good detectivity (D*) value up to 7.77 × 1012 Jones. Moreover, it shows excellent electrical stability and mechanical flexibility as bended with various curvatures for 2000 cycles, and the R values of photodetector array on a large-area film show a very narrow distribution, resulting from the homogeneous and compact perovskite film. More importantly, 80% of initial performance can be maintained even exposed to ambient condition (humidity ∼45%, temperature ∼30 °C) for 700 h without encapsulation, which is attributed to the stability of perovskite material and perovskite/electrodes interface, as well as the passivation of slightly excess PbI2 in perovskite film. The results show that fully-printed, flexible perovskite photodetector with good scalability and stability can be achieved via R2R printing technique, which provides an alternative strategy for perovskite application in low-cost optoelectronic devices.