Perovskite Quantum Dot–ZnO Nanowire Composites for Ultraviolet–Visible Photodetectors

In this study, we developed a photodetector and humidity sensor based on zinc oxide nanowires (ZnO NWs) with CsPbBr3 perovskite quantum dots (PQDs). PQDs are ideally suited to semiconductor sensors due to their excellent optoelectronic properties, including the high carrier mobility, high absorption coefficient, and effective charge transfer at heterojunctions. The ZnO NWs were created via chemical bath deposition, and PQDs were created via a one-step injection method. I–V curves revealed that the current leakage of PQD/ZnO NWs was lower than that of ZnO NWs. PQD/ZnO NWs also generated a larger number of photogenerated carriers, which improved sensor responses, regardless of the illumination wavelength. Under UV illumination, the photocurrent of both structures decreased with an increase in relative humidity; however, under green light illumination, the photocurrent of PQD/ZnO NWs increased with humidity. This study also investigated the optical properties of the two structures as candidate sensor mechanisms.