Dual-functional interface engineering of CsPbBr3 quantum dots for photon downshifting composite films in crystalline silicon solar cells

Crystalline silicon solar cells (CSSCs) continue to dominate the photovoltaic market due to their decreasing costs and increasing efficiency. However, as CSSC efficiency approaches the Shockley–Queisser limit, conventional strategies for further performance improvement have become increasingly ineffective. The photon downconversion effect offers a promising solution. However, obtaining stable and efficient downconversion materials remains a significant challenge. This study proposes using trioctylphosphine (TOP) as a passivating ligand for CsPbBr 3 quantum dots, combined with a ZnO protective layer constructed using Zn(C 2 H 5 ) 2 , to enhance stability and performance. The use of 70 μL TOP and 30 μL Zn(C 2 H 5 ) 2 leads to the optimal downshifting film. The resulting CsPbBr 3 QD@TOP@ZnO/EVA composite film exhibits a significant 0.85% enhancement in CSSC efficiency. In addition, after an 18-day PCE stability test on the device, its PCE efficiency stability was comparable to that of EVA film, demonstrating its potential to enhance solar cell performance by downconverting.