A novel blanket annealing process to achieve highly transparent and conducting Al doped ZnO thin films: Its mechanism and application in perovskite solar cells

•A unique Zn blanket annealing process to control compensating defects in AZO thin films.•Decrease in compensating defects in AZO due to excess Zn diffusion.•As low as 8.8 Ω/sq sheet resistance and 90% visible transmittance of AZO is at par with commercial ITO.•Developed film performance as TCO in perovskite solar cells is quite good.