Simultaneous enhancement in performance and UV-light stability of organic–inorganic perovskite solar cells using a samarium-based down conversion material

Abstract

Extending the spectral response from the ultraviolet (UV) to the visible-light range and enhancing the UV-light stability are two remaining challenges for the development of perovskite solar cells (PSCs). Lanthanide complexes show a broad absorption range in the UV region and can down convert UV-light into visible-light; thus, they are potentially able to improve the device performance of PSCs. Herein, we report the fabrication of PSCs with a novel samarium (Sm)-based down conversion nanomaterial, Sr₂CeO₄:Sm³⁺ (SCOS). In comparison to the control device without a SCOS layer, the SCOS-coated device shows an enhancement of 11.4% in photocurrent and 16.2% in average power conversion efficiency (PCE), due to the harvesting and re-emitting of UV-light in the visible range through the SCOS layer. Significantly, the SCOS-coated devices retain 50% of their initial PCE for 60 hours under continuous UV-light illumination and even after 60 days of storage under ambient environment conditions, whilst for the control device the longevity is 15 hours and 26 days, respectively. The results suggest that the SCOS layer makes an important contribution in terms of both enhanced photovoltaic performance and prolonged device stability by reducing photo-loss and photo-degradation.