Glass-to-glass encapsulation with ultraviolet light curable epoxy edge sealing for stable perovskite solar cells

Perovskite solar cells (PSCs) have rapidly achieved power conversion efficiencies comparable to those of first generation c-Si and second generation thin film solar cell technologies. Although studies on upscaling of PSC technology for practical applications are growing, operation stability remains a challenge and need to be addressed. Ingress of ambient moisture into the device architecture and subsequent decomposition of organometal halide perovskite absorber is identified as one of the major reason for poor operational stability of PSCs. In this letter, we report a low temperature glass-to-glass encapsulation of PSCs using ultraviolet (UV) light curable epoxy edge sealant. Controlled UV irradiation induces epoxy cross-linking and hermitic glass-to-glass encapsulation at <50 °C and therefore device retains 85% of its original performance. Nevertheless, conventional encapsulation carried out using surlyn thermoplastic gasket at 120 °C decreased the device's original performance by about 25%. Preliminary stability studies carried out by aging the PSCs at 30 °C, 50% humidity show that UV cured epoxy edge sealing effectively prevent the moisture ingress and thus improve the device stability beyond 70 days.