Direct Photo-Patterning of Perovskite Nanocrystals with Siloxane Resin Showing Highly Stable Luminescence

Metal halide perovskite nanocrystals (PeNCs) are promising light emitting materials for color-converting light-emitting diodes (CC-LEDs) due to their high absorption coefficient, narrow full width at half maximum (FWHM) and easily tunable bandgap. However, PeNCs face challenges, such as instability against chemicals and high humidity, as well as limited patternability without any additive, which limit their potential as color conversion layer (CCL) in CC-LEDs. Also, there are no reports regarding stable PeNCs patterns, despite the achievements of their high-resolution patterning using ligand crosslinkers.<br/>Herein, we report highly stable PeNCs (green emitting MAPbBr₃/resin composites) patterns encapsulated in siloxane resin which is synthesized by the sol-gel reaction between methoxy groups of (3-methacryl oxypropyl) trimethoxysilane (MPTS) and hydroxyl groups of diphenylsilanediol (DPSD). The synthesized siloxane resin provides physical protection to core materials by crosslinking between methacrylate functionalized siloxane resin and unsaturated hydrocarbon of organic ligands (e.g., oleic amine or oleic acid) via UV-induced free radical reactions, resulting in direct optical patterning without ligand crosslinkers.<br/>By introducing the siloxane resin, PeNCs patterns demonstrate high photoluminescence quantum yield (PLQY) in various harsh conditions: in DI water (&gt; 100 days), ambient conditions (&gt; 150 days) and under 40 °C/RH 70% (&gt; 8 hours) without additional encapsulation process, since the siloxane resin suppresses hydrolysis of PeNCs and controls permeation of H₂O molecules moderately. Moreover, direct optical patterning with siloxane resin can be applied to various inorganic light emitting materials (red emitting CdSe QDs/resin composites).<br/>We believe that our material design, which combines MAPbBr₃and CdSe QDs with siloxane resin, will offer a universal solution, demonstrating high levels of pattern stability in harsh conditions while enabling direct optical patterning without the need for ligand crosslinkers, simultaneously.