High-performance near-infrared vertical organic phototransistors through bulk heterojunction integration

Organic phototransistors (OPTs) have emerged as promising candidates for advanced photodetector applications due to their high sensitivity, flexibility, and low-power operation. However, the photodetection performance of traditional OPTs with lateral structures is often compromised by extended charge carrier transport paths, leading to increased carrier trapping or recombination. Addressing this challenge, we introduce vertical organic phototransistors (VOPTs) with significantly shorter channel lengths (about 150 nm), aiming to enhance photoresponse performance. Through the fabrication of VOPTs incorporating PDVT-10:Y6 bulk heterojunctions, and a detailed investigation into the optimization strategies, we achieved a substantial improvement in device performance. The optimized VOPTs exhibited a photoresponsivity of 0.4 A/W, a specific detectivity of 1.2 × 1012 Jones under 808 nm near-infrared light, coupled with a rapid response time of approximately 20 ms—among the fastest reported for VOPTs to date. This study not only advances the understanding of VOPT device physics but also highlights the potential of integrating bulk heterojunctions for the development of high-performance VOPTs.