This work was supported by the National Key Basic Research Program of China (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)
Nanoscale Research Letters
Heterojunctions, Photovoltaic cells
ZnO nanoneedle arrays were grown vertically on a fluorine-doped tin oxide-coated glass by hydrothermal method at a relatively low temperature. A self-powered photoelectrochemical cell-type UV detector was fabricated using the ZnO nanoneedles as the active photoanode and H2O as the electrolyte. This solid-liquid heterojunction offers an enlarged ZnO/water contact area and a direct pathway for electron transport simultaneously. By connecting this UV photodetector to an ammeter, the intensity of UV light can be quantified using the output short-circuit photocurrent without a power source. High photosensitivity, excellent spectral selectivity, and fast photoresponse at zero bias are observed in this UV detector. The self-powered behavior can be well explained by the formation of a space charge layer near the interface of the solid-liquid heterojunction, which results in a built-in potential and makes the solid-liquid heterojunction work in photovoltaic mode.
Li et al.: ZnO nanoneedle/H2O solid-liquid heterojunction-based self-powered ultraviolet detector. Nanoscale Research Letters 2013 8:415.