Self-powered nanosensors and nanosystems have attracted significant attention in the past decades and have gradually become the most desirable and promising prototype for environmental protection/detection because no battery is needed to power the device. Therefore, in this paper a design is proposed for a self-powered photodetector based on triboelectric nanogenerator (TENG) configuration. 3D dendritic TiO2 nanostructures are synthesized as the built-in UV photodetector as well as the contact material of the TENG. The cost-effective, robust, and easily fabricated TENG-based photodetector presents superior photoresponse characteristics, which include an excellent responsivity over 280 A W-1, rapid rise time (18 ms) and decay time (31 ms), and a wide detection range of light intensity from 20 mu W cm(-2) to 7 mW cm(-2). In the last part of the paper, a stand-alone and self-powered environmental sensing device is developed by applying poly(methyl methacrylate) (PMMA) substrates and springs to assemble the TENG-based photodetector. These results indicate that the new prototype sensing device based on the TENG configuration shows great potential as a self-powered photodetector.