Switchable Anion Exchange in Polymer-Encapsulated APbX3 Nanocrystals Delivers Stable All-Perovskite White Emitters

We report a one-step synthesis of halide perovskite nanocrystals embedded in amphiphilic polymer (poly(acrylic acid)block-poly(styrene), PAA-b-PS) micelles, based on injecting a dimethyl-formamide solution of PAA-b-PS, PbBr2, ABr (A = Cs, formamidinium, or both) and additive molecules in toluene. These bifunctional or trifunctional short chain organic molecules improve the nanocrystal-polymer compatibility, increasing the nanocrystal stability against polar solvents and high flux irradiation (the nanocrystals retain almost 80 degrees 0 of their photoluminescence after 1 h of 3.2 w/cm(2) irradiation). If the nanocrystals are suspended in toluene, the coil state of the polymer allows the nanocrystals to undergo halide exchange, enabling emission color tunabili . If the nanocrystals are suspended in methanol, or dried as powders, the polymer is in the globule state, and they are inert to halide exchange. By mixing three primary colors we could prepare stable, multicolor emissive samples (for example, white emitting powders) and a UV-to-white color converting layer for light-emitting diodes entirely made of perovskite nanocrystals.

Automated summary

The study presents a one-step synthesis method for halide perovskite nanocrystals embedded in amphiphilic polymer micelles, with the addition of organic molecules to enhance compatibility and stability as well as enable color tunability. By mixing three primary colors, stable multicolor emissive samples and UV-to-white color converting layers entirely made of perovskite nanocrystals can be prepared.