Light and Shadow Effects in the Submerged Photolytic Synthesis of Micropatterned CuO Nanoflowers and ZnO Nanorods as Optoelectronic Surfaces

A facile surface patterning method using low temperature and atmospheric pressure is desirable for optoelectronic device fabrication. In this work, we demonstrate a fascinating dynamic fabrication method using light and shadow effects in submerged photolytic synthesis (L&S patterning) for CuO nanoflowers (NFs) and ZnO nanorods (NRs) surface micropatterning. In addition, galvanic reactions using appropriate metals can efficiently enhance NFs and NRs patterning. The principal of illumination effect was studied by photoelectrochemical measurements. Light induces a photoassisted localized cathodic reaction on the oxide surface through photoexcited electrons. Simultaneously, the shadowing effect from using a metal mesh prevents oxide formation, while galvanic reactions take place on the light-exposed area. This dynamic method enables facile and efficient surface patterning in water. Photoemission electron microscopy (PEEM) images and cathodoluminescence in SEM (SEM-CL) spectral analyses prove the useful electron and light emission properties of the products, respectively. A detailed discussion of their optoelectrical properties is given. The environmentally benign L&S patterning method does not require any organic catalyst to function in neutral water. Thus, this method has opened the possibility for facile, futuristic, one-pot, one-step, large-scale optoelectronic device fabrication.