Dual Function Polymer Ligands of Perovskite Nanocrystals for Extraordinary Water Resistance and X-Ray Imaging Scintillators

Lead perovskite nanocrystals (PNCs) have shown great potential for optoelectronic device applications due to their excellent optoelectronic properties. However, the application of PNCs is significantly limited due to the inferior stability resulting from the highly dynamic ligands on the surface. Herein, poly(maleic anhydride-alt-1-octadecene) (PMAO) with low molecular weight (M-n = 1911) is synthesized by copolymerization and used as multi-dentate ligands to prepare CsPbBr3 PNCs via hot injection. The PNCs exhibit excellent water resistance, which maintains fluorescence for 2600 min while conventional PNCs are completely destroyed after 100 min. Density functional theory calculations demonstrate that PMAO as a multi-dentate ligand has higher adsorption energy to the surface of PNCs. Due to the large amount of extra anhydride structure of PMAO, PMAO-PNCs are used as a cross-linking agent to directly prepare flexible films by an in situ one-step polymerization reaction with 1,3-bis(3-aminopropyl) polydimethylsiloxane (PDMS-NH2). The fluorescent flexible films show great potential for applications including X-ray imaging scintillators and flexible light-emitting diodes (LEDs). This study can provide guidance to prepare ultra-stable PNCs and flexible perovskite films with good stability in a simple and efficient way.