Tunable UV response and high performance of zinc stannate nanoparticle film photodetectors

High-performance photodetectors are costly due to either the expensive nature of active materials or sophistication in the fabrication process required to meet performance targets. In this work, low-cost metal stannate based nanostructures are demonstrated as active materials for high-performance UV photodetectors. A robust, inexpensive, and scalable drop-casting process was successfully developed to fabricate thin film devices composed of amorphous ZnSnO 3 nanocubes and/or polycrystalline Zn 2 SnO 4 –SnO 2 nanoparticles with different optical and electronic structures. Moreover, the Zn 2 SnO 4 –SnO 2 heterojunction nanoparticles were directly obtained by thermal treatment of amorphous ZnSnO 3 nanocubes. Large-area, uniform, and continuous film photodetectors were achieved with pronounced and fast response upon exposure to UV illumination ( λ < 370 nm), showing both rise and decay times less than 1.0 s. More advantages based on these two stannate nanostructures were observed compared with their counterparts, such as ZnO, SnO 2 , Zn 2 SnO 4 , ZnO–SnO 2 individual nanostructures or film photosensors, including high photo-sensitivities ( S > 10 2 and ∼10 3 was achieved for ZnSnO 3 and Zn 2 SnO 4 –SnO 2 photodetectors, respectively) and excellent responsivity (as high as 0.5 A W −1 at 5.0 V bias from the Zn 2 SnO 4 –SnO 2 photosensors) under low light intensity. This work provides a simple, cost-effective and tunable processing strategy to synthesize and apply earth-abundant metal stannate based nanomaterials for high performance UV photodetectors and other optoelectronic devices.