Optimization of fluorinated interfacial layers with minimal surface coverage for hybrid perovskite materials

Abstract

A little is enough: ultrathin fluorous layers improve perovskite surface properties.

Tailoring Defect Passivation for Efficient and Stable Perovskite Solar Cells via an Ionic Liquid Additive

“…14−16 Among these, additive engineering is considered the simplest and most effective way to passivate the defects of perovskite films. For example, ionic liquid, 17 perfluorinated additives, 18 and small organic molecules 19 have been widely added into perovskite precursors for defect passivation. During the process, explanations based on Lewis acid−base theory have been generally accepted, for which Lewis acid groups such as carboxylic acid groups, sulfonic acid groups, and phosphoric acid groups can coordinate with Pb 2+ and electron-rich Lewis base substances such as aromatic rings and amino groups can provide lone-pair electrons and affect halogens in the perovskite structure, thus improving stability.…”

“…To address these problems, a wide range of strategies including interface engineering, additive engineering, and dimension engineering have been employed. − Among these, additive engineering is considered the simplest and most effective way to passivate the defects of perovskite films. For example, ionic liquid, perfluorinated additives, and small organic molecules have been widely added into perovskite precursors for defect passivation. During the process, explanations based on Lewis acid–base theory have been generally accepted, for which Lewis acid groups such as carboxylic acid groups, sulfonic acid groups, and phosphoric acid groups can coordinate with Pb 2+ and electron-rich Lewis base substances such as aromatic rings and amino groups can provide lone-pair electrons and affect halogens in the perovskite structure, thus improving stability. − In particular, ionic liquids (ILs) that have both Lewis acid and Lewis base properties can be used as useful additives in PSCs, which can passivate positive and negative defects through chemical interactions with perovskite components .…”