Laser‐Free Mesh‐Structured Semitransparent Cu ₂ ZnSn(S,Se) ₄ Photovoltaics for Optoelectronic Building‐Integrated Applications

Transparent photovoltaics (PVs) attract considerable attention for building‐integrated photovoltaics (BIPV) and multifunctional building envelopes, including media facades, where both power generation and optical transparency are essential. In this study, a new approach is developed for fabricating mesh‐patterned, semitransparent Cu ₂ ZnSn(S,Se) ₄ (CZTSSe) thin‐film solar cells using a photolithography‐based bottom‐up manufacturing process. By defining transparent openings before the solar cell absorber deposition, this method avoids postdeposition etching, which often causes thermal degradation and detrimental secondary phases. The resulting device exhibits an average visible transmittance (AVT) of 67.45% and a power conversion efficiency (PCE) of 1.59%, demonstrating proof of concept. In addition, an AlGaInP red LED is integrated into the transparent region of a CZTSSe cell to create a dual‐function optoelectronic module. The hybrid device maintains open‐circuit voltage and fill factor values similar to those of the original transparent PV. Although the short‐circuit current density decreases by 5.9%, the PCE declines by only 0.1%. These results indicate that this laser‐free, mesh‐structured CZTSSe platform is a promising candidate for next‐generation BIPV systems requiring both energy generation and visual display functionality.