ABSTRACT Substrate engineering plays a crucial role in modulating charge carrier transport in nanohybrids. This provides a pathway for designing next‐generation, substrate‐optimized self‐powered photodetectors for wearable, flexible, and smart photonic applications. Here, we present a self‐powered photodetector of Cu 2 S/WS 2 nanohybrid at different flexible substrates featuring enhanced light induced exciton generation. The presence of trap centers generally hampers the effective performance of photodetectors and influences their photodetection characteristics. However, in certain cases trap assisted carrier dynamics lead to contradictory behavior where the trapping of one type of charge carrier results in an EQE exceeding 100% due to photoconductive gain. Among all tested substrates, the ITO‐Cu 2 S/WS 2 ‐ITO device exhibits the highest External Quantum Efficiency (EQE) of 299.81%, demonstrating superior photo‐to‐electron conversion capability. The high EQE correlates with its excellent detectivity (7.97 × 10 10 cm. Hz 1/2 . W −1 ), making it the best‐performing configuration. In contrast, devices on cotton, paper, and glass show significantly lower EQE due to substrate‐induced defects or inefficient carrier transport. This study paves the way for designing a new class of substrate‐engineered materials with potential applications in next‐generation photonic devices. This study helps to understand the trapping mechanisms, as well as the role of substrates in governing device performance particularly in metal semiconductor metal‐based photodetectors.
Rani et al. (Fri,) studied this question.