Phosphonic Acid Stabilized Colloidal CsPbX3 (X=Br, I) Perovskite Nanocrystals and Their Surface Chemistry

We demonstrate the improved stability of colloidal CsPbX3 (X=Br, I) perovskite nanocrystals (NCs) using the phosphonic acid ligand. Photoluminescence spectra indicated that the phosphonic acid-based CsPbX3 perovskite NCs had stable optical properties in solution, and inductively coupled plasma-mass spectrometry provided a deeper insight of their decomposition mechanism and the surface chemistry of CsPbX3 NCs. With the aid of liquid chromatography-mass spectrometry, we show more detail in the ligand binding of NC solutions, suggesting that strong binding of phosphonic acid ligands is the key to stabilize the NC structures, probably with both metal and halide ions on the NC surface.