3-D architecture between indium tin oxide nano-rods and a solution processed CuInGaS2 absorber layer for thin film solar cells

The performance of thin film solar cells can be significantly enhanced by efficient light management. In this study, we integrated one-dimensional indium tin oxide (ITO) nanorods into CuInGaS2 (CIGS) films to fabricate 3-D nanostructured thin film solar cells. 400, 600, and 1000 nm ITO nanorod substrates were used as back contact electrodes. Precursor solutions of Cu, In, and Ga with and without binder materials were prepared to fill the gaps between the ITO nanorods and increase the thickness of the CIGS films, respectively. Heat treatments both in air and in H2S were applied to form polycrystalline CIGS films while minimizing carbon impurities. 3-D nanostructured solar cell devices with Al,Ni/AZO/i-ZnO/CdS/CIGS/ITO nanorods/Glass structures were fabricated and characterized. Under standard irradiation conditions, the 600 nm ITO nanorod solar device was found to have the maximum power conversion efficiency of 6%. This superior efficiency may be attributed to enhanced light absorption and complete gap filling.