Low-Cost and Stable Semitransparent Crystalline Silicon Solar Cells via Two-Step Laser Processing

Semitransparent (ST) solar cells hold promise for application in building-integrated photovoltaics and vehicles, but current ST solar cells often exhibit problems such as color uniformity, low efficiency, and poor stability. This study proposes a novel method of fabricating ST crystalline silicon solar cells with average visible transmittance (AVT) controlled via hexagon-arranged microhole patterns using two-step laser processing. The optimal configuration of microholes was evaluated, with the AVT as functions of microhole diameter and distance. The two steps of laser processing, avoiding the shunt problem during cell fabrication with one-step laser to form microholes, were individually performed. Thus, 80% and 20% of the thickness of silicon wafer were respectively removed via melting before and after cell fabrication. The advanced fabrication of a silicon heterojunction solar cell was thus conducted, and a wet procedure was responsible for removing the damage caused by first-step laser processing. Therefore, the performance of the cell mainly depended on the damage due to second-step laser processing. We finally prepared ST silicon solar cells with power conversion efficiency of 10.2% at AVT of 13%, damp-heat endurance, and neutral colors. This fabrication strategy represents a significant step toward the development of efficient ST solar cells and their application.