Strongly luminescent and highly stable core-shell suprastructures from in-situ growth of CsPbBr3 perovskite nanocrystals in multidentate copolymer micelles

Abstract

Lead halide perovskite nanocrystals (NCs) have shown exceptional optoelectronic characteristics and photovoltaic performance; however, their instability has limited their use in optoelectronic applications. Herein, we introduce a facile and effective in-situ synthesis strategy to prepare stable core-shell colloidal perovskite nanocrystal-polymer micelle composites (abbr. ap-POSS-PMMA-b-PDMAEMA@CsPbBr3) by using amphiphilic copolymer (abbr. ap-POSS-PMMA-b-PDMAEMA) self-assembled “reverse micelle” templates. The amphiphilic block copolymer with hydrophobic (ap-POSS and polymethylmethacrylate, PMMA) and hydrophilic blocks (poly 2-(dimethylamino)ethyl methacrylate, PDMAEMA) can be regulated to self-assemble into “reverse” micelles. The micelle serves as a confined nanoreactor during perovskite crystallization, which passivates the perovskite surface by forming a multidentate capping shell and yields the formation of multi-nanocubes with size between 6 and 8 nm and a photoluminescence quantum yield (PLQY) that surpasses 60%. Benefitting from femtosecond transient absorption (fs TA) and time-resolved photoluminescence (PL) spectroscopy studies, the excited carrier dynamics of the obtained composites substantiate fewer internal band-gap trap states from micelle-induced CsPbBr3 NCs. The films cast from these composites showed enhanced water-resistant properties as compared to bare NCs and previously reported encapsulated NCs. Therefore, the copolymer “reverse” micelle induced in-situ grown NCs provide a potential approach for further engineering the morphology of NC-based composites and open the door to potential scalable and robust optoelectronic applications.