Controlled Nucleation and Crystallization for Efficient Solution-Processed CIGS Solar Cells

Solution-processed CIGS solar cells present a cost-effective alternative for photovoltaic production, yet they exhibit significant power conversion efficiency (PCE) losses compared to vacuum-deposited counterparts. The performance limitations originate from inferior film quality, which stems from fundamentally different growth mechanisms. Here, we propose a novel preannealing strategy for the CIGS precursor film, which can regulate the nucleation and crystallization pathway. Characterization reveals that preannealing enlarges nucleation sizes while reducing nucleation sites, thereby promoting grain growth and yielding high-quality absorbers with compact morphology, enhanced crystallinity, and fewer defects. Ultimately, the optimized CIGS solar cells exhibit an impressive PCE of 17.51%, which is among the top values for solution-processed CIGS solar cells. This nucleation and crystallization regulation strategy provides a framework for growth optimization to achieve high-performance, solution-processed chalcopyrite photovoltaics.