Synthesis of highly-transparent Al-doped ZnO porous network thin films

Highly-transparent Al-doped ZnO (ZAO) porous network thin films are prepared via solvothermal method for the first time. It is found that the morphology of the nanostructures evolved from nanosheets to porous network structures because of the different annealing temperature. The incorporation of Al and the contents of NaOH play important roles in the morphology of porous network nanostructures. A growth mechanism is proposed to explain these findings. Al is successfully doped into the ZnO wurtzite lattice structure as revealed by X-ray diffraction (XRD) and verified by the energy dispersive X-ray detector (EDX). The unique nanostructure thin films exhibit a typical wurtzite structure and strong violet emission. Ultraviolet-visible spectroscopy (UV-vis) shows the films have a good transparency, and the absorption edges are obviously blue shifted with a temperature increase. By optimizing the reaction parameters, the morphology, and size of the network thin films could be tailored, which will be very significant for fabricating novel and surface morphology controlled photocatalysis, optoelectronics, solar energy and self-cleaning devices.