Real-Time Ultraviolet Monitoring System with Low-Temperature Solution-Processed High-Transparent p–n Junction Photodiode with a Fast Responsive and High Rectification Ratio

We introduce an enhanced performance organic–inorganic hybrid p–n junction photodiode, utilizing poly[bis(4-phenyl) (2,4,6-trimethylphenyl)amine] (PTAA) and ZnO, fabricated through a solution-based process at a low temperature under 100 °C. Improved interfacial electronic structure, characterized by shallower Gaussian standard deviation of the density-of-state distribution and a larger interface dipole, has resulted in a remarkable fold increase of ∼102in signal-to-noise ratio for the device. This photodiode exhibits a high specific detectivity (2.32 × 1011Jones, cm×Hz×W−1) and exceptional rectification ratio (5.47 × 104at ±1 V). The primary light response, concentrated in the optimal thickness of the PTAA layer, contributes to response over the entire UVA region and rapid response speed, with rise and fall times of 0.24 and 0.64 ms, respectively. Furthermore, this work demonstrates immense potential of our device for health monitoring applications by enabling real-time and continuous measurements of UV intensity.