Water-driven CsPbBr3 nanocrystals and poly(methyl methacrylate)-CsPbBr3 nanocrystal films with bending-endurable photoluminescence

Perovskite nanocrystals are regarded as next-generation functional materials for display applications, especially for flexible liquid crystal displays (LCDs). As a potential component of flexible LCD backlights, perovskite nanocrystal films are facing a challenge issue of deformation-induced shift of photoluminescence, leading to an image distortion. To date, most synthesis methods have involved the use of organic solvent in precursor solutions, such as N,N-dimethylformamide and dimethyl sulfoxide, which poses a potential threat to the environment, health and security. In this work, we demonstrate the feasibility to produce microsized CsPbBr3 crystals with deionized water as the precursor solvent via an environmental-friendly and cost-efficient approach and CsPbBr3 nanocrystals with green (similar to 522 nm) and blue (similar to 493 nm) emissions from the microsized CsPbBr3 crystals in toluene under sonication. The blue-emitting nanocrystals exhibit a photoluminescence (PL) quantum yield of 80%, much larger than 61.4% of the CsPbBr3 nanocrystals made by an anti-solvent method; the green-emitting nanocrystals exhibit better stability than those made by the antisolvent method over 9 days. Using the green-emitting CsPbBr3 nanocrystals, we prepare a bilayer structure with a poly(methyl methacrylate)-CsPbBr3 nanocrystal film on a polyethylene terephthalate plate. The films exhibit bending-endurable photoluminescence, i.e. the wavelength of the PL peak remains unchanged, for local radius of curvature of the bilayer up to 10.07 mm under bending. This study opens a new avenue to potentially produce microsized perovskite crystals without harmful organic solvents and bending-endurable backlight films for the applications in flexible display.

Automated summary

This study demonstrates the successful production of microsized CsPbBr3 crystals and CsPbBr3 nanocrystals using deionized water as the precursor solvent, showing their potential applications in flexible LCD backlights. The nanocrystals exhibit high PL quantum yields and improved stability, providing a promising avenue for environmentally-friendly and bending-endurable backlight films in flexible display applications.