LAUSR

Transparent, superhydrophilic materials are indispensable for their self-cleaning function, which has become an increasingly popular research topic, particularly in photovoltaic (PV) applications. Here, we report hydrophilic and superhydrophilic ZnO by varying the morphology for use as a self-cleaning coating for PV applications. Three different ZnO microstructures, such as ZnO nanorods (R-ZnO), ZnO microflowers (F-ZnO), and ZnO microspheres (M-ZnO), were developed by hydrothermal methods. The surface morphology by using X-ray diffraction (XRD), wettability behavior by using water contact angle (WCA) measurements, structural and optical properties by using photoluminescence (PL), Raman, and UV–vis spectrophotometry, and defect estimation by using X-ray photoelectron spectroscopy (XPS) of the ZnO nanostructured films were systematically investigated. XRD confirmed the formation of the hexagonal wurtzite structure of ZnO. The average crystallite sizes of prepared R-ZnO, F-ZnO, and M-ZnO were found to be 28.95, 11.19, and 41.5 nm, respectively. The band gap values of ZnO nanostructures were calculated from the UV–vis absorption spectrum and found to be 3.6, 3.3, and 3.1 eV for R-ZnO, F-ZnO, and M-ZnO, respectively. The WCAs for R-ZnO and F-ZnO were 20.2 and 11.19°, respectively, while M-ZnO behaved like a superhydrophilic material having a WCA of 2.8°.