This work reports on the synthesis and the main physical and chemical properties of ZnO nanoparticles synthesized by an entirely green Bio-physical-chemical process using natural dye extract from Adansonia digitata leaves as an efficient reduction/oxidizing agent. Their structural and surfaces properties by electron microscopy, X-rays diffraction, Raman and TGA, as well as gas adsorption analysis are reported.

ZnO nanorods arrays were prepared on soda lime glass substrate by pulsed laser deposition method. Hexagonal rod-like ZnO rods were obtained under different conditions. Well-defined ZnO nanorods arrays were selected among different samples having various morphologies and sizes already studied by X-ray diffraction (XRD) and atomic force microscopy (AFM). Here, we report on the contact angle measurement (CAM) of one of these samples. A systematic change of the surface wettability is observed in W-doped ZnO nanostructures. The water contact angle (WCA) of a 1 wt.% of WO3 target content was found to be the transition doping level from hydrophilic surface to a hydrophobic surface. We attributed the transition in surface wettability of the film with the doping to incorporation increase of tungsten into the film. Such characteristic surface wettability can play a key role in the adhesion of various layers on W-ZnO nanorods arrays for optoelectronic device applications.