Multi-dynamics and emission tailored fluoroperovskite-based down-conversion phosphors for enhancing the current density and stability of the perovskite solar cells

Abstract

State-of-the-art and innovative research is being intensively employed on perovskite solar cells (PSCs) to expand their frontiers further. This study is a successful attempt to drive the limit of photocurrent density (J_sc) beyond conventional PSCs (which typically utilize the visible spectrum alone) through a nonlinear optical phenomenon called down-conversion (DC). The use of DC luminescence to harness the UV region from the solar spectrum is explored by utilizing Eu³⁺ activated RbCaF₃, a fluoroperovskite-based phosphor material. It is observed that PSCs, which used RbCaF₃:Eu³⁺ incorporated TiO₂ electron transport layer (ETL), enhanced their J_sc and UV stability compared to those with pristine TiO₂-oriented ETL. Such improvement in the aforementioned devices is due to the result of converting high-energy UV photons to effectively absorbable low-energy visible photons for perovskite absorbers. Overall, the DC-aided PSC offered a substantial J_sc of 23.54 mA cm⁻² (9.2% superior to the conventional PSC) and boosted its power conversion efficiency (PCE) from 11.2% to 13.3%. It is evident that DC-based PSCs show a much better shelf-life when compared to conventional PSCs. This unique approach for boosting the J_sc with enhanced stability can be utilized for the potential applications of PSCs.