Eco-friendly Solvent-Processible and highly luminescent perovskite nanocrystals with polymer zwitterions for Air-Stable optoelectronics

Perovskite quantum dots (QDs) have been studied as building blocks for next-generation optoelectronics owing to the wide tunability of their crystal structure and shape. One of the greatest hurdles for perovskite QDs is material instability when exposed to water, heat and polar solvents. Furthermore, the toxicity of solvents used for perovskite materials can lead to hazardous solution processes, unfavourable for large-area processes. In this paper, we report a perovskite surface engineering technique using zwitterionic polymer ligands, poly(carboxybetaine acrylamide) (PCA), to produce ultrastable perovskite QDs in polar solvents. We demonstrate that PCA polymers have a strong binding energy on the perovskite surface as coordinate bonds, according to experimental data and density functional theory (DFT) calculations. Moreover, the QDs produced with PCA maintained photoluminescence stability for over 50 d and uniform dispersion in alcohol solvents, which shows potential for an eco-friendly processability. Finally, we developed a band-gap-tuned white light-emitting diode (WLED) and produced roll-to-roll-processed thin films using slot-die coating.