Impact of Ligand-Mediated Inductive Effects on Electrochemical p-Doping of CsPbBr ₃ Nanocrystals

Lead halide perovskite nanocrystals (NCs) are promising materials for light-emitting diodes (LEDs) due to their wavelength tunability, narrow emission line width, and high photoluminescence quantum yield. Oftentimes, these devices suffer from charge carrier imbalance and reduced charge injection because as-synthesized NCs are covered by long aliphatic ligands. Here, we report ligand exchange to small electron-withdrawing or -donating cinnamate ligands. We probe the influences of the ligands’ inductive effect on hole injection by photoluminescence spectroelectrochemistry (PL SEC). We find that hole injection into NCs covered by electron-withdrawing ligands is facilitated, and hole-only devices exhibit higher currents compared to electron donating ligands. Our work highlights the potential of PL SEC as a powerful tool to rationalize the performance of lead halide perovskite NCs in LEDs.