A comparative study of the effect of transparent conducting oxides on the performance of \(\hbox {Cu}_{2}\hbox {ZnSnS}_{4}\) thin film solar cell

One major factor affecting the performance of the kesterite \(\hbox {Cu}_{2} \hbox {ZnSnS}_{4}\) (CZTS) thin film solar cell is its low open circuit voltage (\({V}_\mathrm{oc}\)). In solar cells, transparent conducting oxides are components which act as electrode elements and their work functions control the open circuit voltage of the device. In this work, numerical modeling and simulation has been used to study the effect of various TCOs fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO) and indium tin oxide (ITO), on the performance characteristics of CZTS thin film solar cell. The usage of ITO gave the best performing device with a conversion efficiency of 9.98%, followed by AZO with 8.41% and FTO with 5.91%. Further optimization of some of the parameters of AZO and FTO shows that they are good alternative to the very expensive ITO. The effect of the variation in operating temperature indicates that AZO and FTO have better thermal stability. In addition, reduction in device thickness, application of FTO/AZO double layer and the filtering of the illumination within the visible spectrum enhanced the overall device performance which yielded an efficiency of 14.46%.