Hydrophobic stabilizer-anchored fully inorganic perovskite quantum dots enhance moisture resistance and photovoltaic performance.

Advances in surface chemistry and manipulation of fully inorganic CsPbI 3 perovskite quantum dots (CsPbI 3 -QDs) have enabled improving the charge transport and photovoltaic performance of CsPbI 3 -QD thin films by replacing their native long-chain, insulating ligands with short-chain ligands. However, the conventional approach based on formamidinium (FA) replacement removes the hydrophobic protective layer, opening the path for moisture penetration and resulting in poor device stability. We demonstrate that short-chain and hydrophobic phenethylammonium (PEA) cations, instead of FA, are efficiently incorporated only onto CsPbI 3 -QD surfaces, confirmed by Fourier-transform infrared, H nuclear magnetic resonance and density functional theory calculations. PEA incorporation leads simultaneously to improved photovoltaic performance and moisture stability of resultant CsPbI 3 -QDs without any change in size, fully inorganic composition, and dimensionality of CsPbI 3 -QDs. Therefore, PEA-incorporated CsPbI 3 -QD solar cells show a high device power conversion efficiency of 14.1% and high moisture stability, retaining over 90% of the initial performance after 15 days under ambient conditions. Aromatic ring-based phenethylammonium is incorporated into CsPbI 3 quantum dots (CsPbI 3 -QDs) by removing their native and insulating oleylammonium ligands. This approach simultaneously improves photovoltaic performance and cubic-phase stability of CsPbI 3 -QD solids under ambient moisture conditions up to 15 days. Thus, CsPbI 3 -QD solar cells show efficient device performance of 14.1% power conversion efficiency with improved device ambient stability. Image 1 • Long-chain, insulating OLA ligands of CsPbI 3 -QDs are exchanged to short-chain, hydrophobic PEA cations. • This strategy enables improved both charge transport and moisture stability of CsPbI 3 -QDs. • PEA incorporations show no changes in size, composition and dimensionality of fully inorganic CsPbI 3 -QDs. • PEA-incorporated CsPbI 3 -QD solar cells show improved device performance up to 14.1% PCE. • Initial PCE of PEA-incorporated CsPbI 3 -QD solar cells retained over 90% for 15 days under ambient conditions. [ABSTRACT FROM AUTHOR]