p-Doped Graphitic Carbon Nitride-Based Flexible Organic Field-Effect Transistor as a Superior Photodetector

Efficient photodetection with organic field-effect transistors (OFETs) demands semiconducting materials that possess excellent light absorption, high carrier mobility, and enhanced charge transport properties. In this work, phosphorus-doped graphitic carbon nitride (p-g-C 3 N 4 ) was successfully integrated as an active semiconductor in OFET-based photodetectors. Phosphorus doping was achieved via a facile wet chemical method, and comprehensive characterization was performed to confirm successful doping and subsequent structural and optical modifications. The resulting OFET devices exhibited enhanced electrical performance, including a high on/off ratio (∼1.7 × 10 5 ), remarkably elevated mobility (up to 458 cm 2 V –1 s –1 ), substantial photoresponsivity (40.68 A/W), and exceptional detectivity (4.74 × 10 13 Jones). Furthermore, under ultraviolet illumination, the devices maintained stable and repeatable performance with broad spectral sensitivity. This study presents, for the first time, p-g-C 3 N 4 as an efficient semiconducting layer for high-performance, flexible photodetection in OFETs. The results suggest that p-g-C 3 N 4 holds significant potential for developing cost-effective, next-generation optoelectronic devices, paving the way for widespread applications in flexible electronics, photodetectors, and optically responsive transistors.