Advanced room-temperature cured encapsulant film for crystalline silicon solar modules: enhancing efficiency with luminescent down-shifting, flame retardancy, and UV resistance†

Abstract

Solar energy sources have garnered significant attention as a renewable energy option. Despite this, the practical power conversion efficiency (PCE) of widely used silicon-based solar cells remains low due to inefficient light utilization. In this study, carbon dots (APCDs) were prepared via a hydrothermal method using ammonium polyphosphate and m-phenylenediamine, then incorporated into a silicone-acrylic emulsion (CAS) to create a luminescent down-shifting (LDS) layer for solar cells. The CAS/APCDs films can be molded at room temperature and exhibit outstanding optical and adhesive properties. Application of CAS/APCDs films on solar cell surfaces effectively enhances photovoltaic performance, increasing current density (J_SC) by 3.5% and overall PCE by 5.7%. Additionally, APCDs enhance flame retardancy in CAS films, increasing the limiting oxygen index from 29.3% to 32.0%, while reducing peak heat release and peak CO release by 20.2% and 38.9%, respectively. Moreover, APCDs absorb UV light and convert it into visible light, mitigating CAS film degradation. The aged CAS/1.0APCDs film exhibits superior morphology and mechanical properties compared to aged CAS film, maintaining 68.9% light transmission. Overall, this study introduces the development of room-temperature cured LDS layers with extended lifespan and flame retardant characteristics, offering promising applications in solar energy technology.