Structural, electronic and optical properties of Cu-Ag and Ti-Ag codoped ZnO as dye-sensitized solar cell photoanode material using density functional theory

Zinc oxide (ZnO) is a promising dye-sensitized solar cell (DSSC) material due to its unique and multifunctional properties. However, its wide bandgap (3.37 eV) hinders effective light absorption in visible light regions, resulting in lower DSSC efficiency. The improvement of the conversion efficiency of ZnO-based DSSC by doping with transition metal (Tm) using copper (Cu), silver (Ag) and titanium (Ti) atoms has mainly been investigated. However, mono-doping has low solubility, limiting further increases light absorption. Thus, the modification of ZnO by codoping with two Tm atoms has been used for photoanodes in DSSC. However, the structural, electronic and optical properties of Tm-Tm codoped ZnO in DSSC are not fully understood. Therefore, the first-principles study based on density functional theory (DFT) is a barely suitable approach to calculating the properties of ZnO.