Low-cost writing method for self-powered paper-based UV photodetectors utilizing Te/TiO₂ and Te/ZnO heterojunctions

It has always been a challenge to prepare self-powered ultraviolet photodetectors (UV PDs) utilizing a green, facile and low-cost method. Here, we provide such an approach for fabricating self-powered photodetectors based on Te nanowire/TiO₂ nanoparticle (NP) and Te nanowire/ZnO nanoparticle (NP) heterojunctions. It is noteworthy that such devices were prepared via simply brushing non-toxic solution-processed Te nanowires and commercial TiO₂ and ZnO nanoparticles onto paper. The as-obtained UV PDs can work under zero bias due to photovoltaic effects from the Te/TiO₂ and Te/ZnO heterojunctions. This study not only presents high-performance UV PDs, but also provides a general and effective method for developing environmentally-friendly and energy-efficient optoelectronic devices for practical applications. The concept of employing daily-use brushes and recyclable paper provides a facile way to fabricate green low-cost PDs.