High-performance self-powered ultraviolet photodetector based on PVK/amorphous-WO3 organic-inorganic heterojunction

Ultraviolet (UV) photodetectors have found wide-ranging applications, ranging from optical communications to chemical detection. High performance UV photodetectors that can be self-powered are highly desirable in many applications as they can minimize energy consumption during operation. Herein, a self-powered UV photodetector, which consisted of poly(9-vinylcarbazole) (PVK)/amorphous-WO3 organic-inorganic heterojunction with PEDOT:PSS as a hole transport layer, was fabricated using a two-step method at low temperature. The effect of WO3, PVK and PEDOT:PSS films on the performances of the photodetector was also investigated. Under optimized parameters, the PEDOT:PSS/PVK/WO3 photodetector exhibited a maximum responsivity of 12.41 AW-1, specific detectivity of 1.80 x 1013 Jones, photo-dark current ratio of 103 at reverse bias and typical rectification characteristic when exposed to 365 nm light irradiation. The photoelectric conversion mechanism of this novel PVK/WO3 heterojunction is discussed using energy band diagrams. This work presents a method to produce a high performance WO3-based heterostructure at low temperature, which has the potential for UV imaging.