High performance vertical organic phototransistor doped with MXene

Abstract

Organic phototransistors are leading the development of next-generation wearable, monitoring, imaging, and sensing technologies due to their light weight, low cost, high yield, compatibility with flexible substrates, and customizable methods for synthesizing optoelectronic properties. However, the long channel length of conventional planar structures, usually in the micron range, greatly reduces the carrier transport efficiency and leads to an increased probability of defect trapping and complex recombination of photogenerated carriers. Here, an organic phototransistor with a vertical channel structure has been demonstrated, in which the active layer is blended with Mxene. Due to the short channel length of vertical structure, the recombination possibility of photogenerated excitons is reduced, and the high ultraviolet sensitivity of Mxene increases the bandwidth of detection. The device exhibits excellent photodetection performance with the photosensitivity of 4.28 × 10⁶, photoresponsivity of 2.39 × 10⁴ A/W, detectivity of 1.04 × 10¹⁷ Jones under irradiation with weak light of 8 μW cm⁻² at 365 nm. This work paves the way for the study of transistors scale and high-performance organic photodetection in the future.