Highly Emissive and Color-Tunable Perovskite Cross-linkers for Luminescent Polymer Networks

Emissive cross-linkers are of special interest for polymer science because of their ability to endow polymer networks with luminescent properties. Methylammonium lead halide perovskite nanoparticles (MAPbCl(x)Br(3-x) NPs) are extensively explored for optical and optoelectronic applications. In this work, MAPbCl(x)Br(3-x) NPs with cross-linkable and polymerizable ligands are successfully prepared as new emissive cross-linkers for polymer networks. Commercially available reagent 2-aminoethyl methacrylate hydrochloride (AMHCl) can act as a ligand to stabilize MAPbBr(3) NPs in solution. Compared with traditional ligands (oleic acid and oleylamine), AMHCl retains the architecture of perovskite effectively and affords polymerizable groups (vinyl) on the surface of perovskites. The as-prepared MAPbCl(x)Br(3-x) NPs can serve as cross-linkers in the radical polymerization of (meth)acrylates by UV-light to form polymer networks. Meanwhile, such cross-linkable emitters exhibit bright luminescence and color-tunability at room temperature, attributed by a unique halide exchange of perovskites between CH3NH3Br and AMHCl, which provides the polymer networks with varied emissive bands. These perovskite-crosslinked networks showed high air stability, water stability, and prominent photoluminescence quantum yields. On the basis of these excellent properties, white light-emitting diodes were successfully fabricated from these perovskite-crosslinked composites with color-coordinate values at (0.316, 0.315), very close to the standard coordinates of white light. This work elucidates a new and convenient technique to convert nanocrystals into luminescent cross-linkers to build functional polymeric networks for technological applications.