The oxidized form of the redox molecule is reduced back to the reduced form OH- at the selleck counter electrode (Pt/FTO) by the electrons that re-entered into the UV detector from the external circuit (e- + OH· → OH-). The circuit was completed in this manner, demonstrating a self-powered UV detection property. Overall, the ZnO nanoneedle

array/water solid-liquid heterojunction is one type of regenerative UV detector. Considering the tunability of the absorption edge of ZnO by simply changing the concentration of the doping element like Al [33, 34] or Mg [35, 36] and excellent spectral selectivity of this system, we suggest that the spectral response should be tailored by elemental doping [37] in a relatively wide range, which presents a promising versatile potential. In addition, the photoresponsivity and time performance of the solid-liquid heterojunction can also be improved by seeking for the optimized electrolyte solution. The simple fabrication technique, low cost, and environmental friendliness (nontoxic composition) further add to the solid-liquid UV detector’s commercial application. Conclusion In conclusion, c-axis-preferred ZnO nanoneedle Torin 1 clinical trial arrays have been successfully prepared on a transparent conductive FTO substrate via a simple hydrothermal

method. A new type of self-powered UV detector based on a ZnO nanoneedle array/water solid-liquid heterojunction structure is fabricated, which exhibits a prominent performance for UV light detection. The photocurrent responds rapidly with UV light on-off switching irradiation under ambient environment. The mechanism of the device

is suggested to be associated with the inherent built-in potential across the solid-liquid interface which works in a Schottky barrier manner that separates the electron-hole pairs generated under UV irradiation. The large relative surface and high crystal quality further promote the photoresponse. This new type of self-powered solid-liquid heterojunction-based UV detector can be a particularly suitable candidate for practical applications for its high photosensitivity; fast response; excellent spectral selectivity; uncomplicated, low-cost fabrication process; and environment-friendly feature. Acknowledgements This work was supported by the National Key Basic Research Program of China Mannose-binding protein-associated serine protease (2013CB922303, 2010CB833103), the National Natural Science Foundation of China (60976073, 11274201, 51231007), the 111 Project (B13029), and the Foundation for Outstanding Young Scientist in Shandong Province (BS2010CL036). References 1. Razeghi M, Rogalski A: Semiconductor ultraviolet detectors. J Appl Phys 1996, 79:7433.CrossRef 2. Munoz E, Monroy E, Pau JL, Calle F, Omnes F, Gibart P: III nitrides and UV detection. J Phys Condens Mat 2001, 13:7115.CrossRef 3. Soci C, Zhang A, Xiang B, Dayeh SA, Aplin DPR, Park J, Bao XY, Lo YH, Wang D: ZnO nanowire UV photodetectors with high internal gain.