Improved efficiency and durability of perovskite solar cells through ionic liquid-[EMIM]PF6 interface modification

Abstract

This study presents a novel strategy for enhancing perovskite solar cells (PSCs) by employing 1-ethyl-3-methylimidazolium hexafluorophosphate ([EMIM]PF6) as an interface modification layer. The authors systematically investigated the impact of this ionic liquid on device efficiency enhancement, as well as on the optical and electronic characteristics of perovskite (PVK) films and NiOx/[EMIM]PF6/(Cs0.1FA0.81MA0.09PbI2.86Br0.14) perovskite interfaces, utilizing various characterization techniques. The results demonstrate that the ionic liquid facilitates dynamic interactions at the interface, enhancing the conductivity of NiOx, aligning energy levels with the PVK, and consequently facilitating charge injection and extraction. The authors' optimized PSC device achieved an impressive Photovoltaic Conversion Efficiency (PCE) of 22.11 % and a current density of 25.23 mA/cm2, demonstrating excellent stability. Notably, the modified film maintained over 75 % of its initial efficiency for more than 800 h. This work presents a straightforward and efficient approach to developing cost-effective, stable, and efficient PSCs.

Keywords

• Perovskite solar cells
• High stability
• Hole transport layer
• Ionic liquid
• [EMIM]PF6
• Interface engineering