Enhancing photovoltaic efficiency in flexible perovskite solar cells through the incorporation of up-conversion Er3+ doped forsterite thin films

Perovskite solar cells (PSCs) have garnered attention due to their high efficiency and cost-effective production. However, their limited absorption in the near-infrared (NIR) range constrains their potential, as NIR accounts for 44 % of the solar spectrum. To address this, we incorporated an erbium-doped forsterite (Mg₂SiO₄:Er3 ⁺) upconversion layer into flexible PSC (MAFA-CsPb(Br,I)₃), converting NIR photons into visible light to enhance power conversion efficiency (PCE). This integration resulted in a significant increase in PCE from 16.1 % to 20.6 %, with the device also showing improved open-circuit voltage (Voc) from 1.05 V to 1.19 V and a higher shortcircuit current density (Jsc) from 22.1 to 23.1 mA/cm2 . Additionally, the thermal and moisture stability of the cells was enhanced, retaining 75 % of their initial efficiency after 500 h under ambient conditions. The use of erbium-doped forsterite as an up-conversion layer presents a promising strategy for overcoming spectral limitations and improving the durability of PSCs, providing a pathway toward more efficient and stable next generation photovoltaic devices.