Rational Design in Developing a Low‐Cost and Eco‐Friendly Transparent CZTS Solar Cell Device for a Building‐Integrated Photovoltaic System

Solar cell devices are now being developed to be transparent to maximize their utilization as a renewable energy source. This includes Cu ₂ ZnSnS ₄ (CZTS) solar cells, which are usually found in opaque form. CZTS solar cells can be transformed into a transparent form using suitable strategies. Here, we successfully fabricate transparent CZTS solar cells on an indium tin oxide substrate. The CZTS precursor, which was previously synthesized via a simple solvothermal method, is diluted using isopropyl alcohol (IPA) prior to the deposition process using the spin coating method. The concentration of CZTS in the dilute ink solution is the key to obtaining the transparent properties of the CZTS layer, which also finally determines the performance of the fabricated transparent CZTS solar cell devices. We found that the transparent CZTS solar cell devices with 15% w/w concentration of CZTS in the dilute solution show better performance compared to 5% and 10% w/w composition. We also found that the solar cell devices using the so‐called superstrate configuration are better compared to using the usual configuration. With further developments, our research opens the path to realizing a transparent CZTS solar cell device, which can be implemented in a building‐integrated photovoltaic system.