Ultrastable highly-emissive amphiphilic perovskite nanocrystal composites via the synergy of polymer-grafted silica nanoreactor and surface ligand engineering for white light-emitting diode

Instability of perovskite nanocrystals driven by their ionic crystal characteristic poses a grand challenge for long-term practical applications in optoelectronic materials and devices. Herein, we report the crafting of amphiphilic perovskite nanocrystal composites (APNCCs) with a set of markedly improved stabilities via capitalizing on polymer-grafted silica nanosheets as nanoreactors in conjunction with surface ligand engineering. First, SiO2 nanosheets grafted with poly(acrylic acid)-block-polystyrene (denoted SiO2 @PAA-b-PS) are rationally designed and exploited as nanoreactors to form SiO2 @CsPbBr3 @PS. Subsequent passivation with small-molecule ligands (L) yields highly emissive SiO2 @CsPbBr3 @ (PS/L) APNCCs with an array of outstanding stabilities against UV, heat, water, long-term storage, and various polar organic solvents. Remarkably, our strategy integrating polymer-grafted SiO2 nanosheet nanoreactor with surface ligand engineering is general and viable. A diversity of stable APNCCs can be readily created. Finally, white light-emitting diode (WLED) with wide color gamut and excellent stability composed of green-emitting SiO2 @CsPbBr3 @ (PS/L) APNCCs is demonstrated. This work highlights the robustness of the synergy of judiciously-designed nanoreactor and surface ligand engineering to produce highly emissive, ultrastable perovskite nanocrystals shielded with soft and hard materials (i.e., possessing a Janus surface chemistry).