Nanorod Suprastructures from a Ternary Graphene Oxide–Polymer–CsPbX₃ Perovskite Nanocrystal Composite That Display High Environmental Stability

Abstract

Despite the exceptional optoelectronic characteristics of the emergent perovskite nanocrystals, the ionic nature greatly limits their stability, and thus restricts their potential applications. Here we have adapted a self-assembly strategy to access a rarely reported nanorod suprastructure that provide excellent encapsulation of perovskite nanocrystals by polymer-grafted graphene oxide layers. Polyacrylic acid-grafted graphene oxide (GO-g-PAA) was used as a surface ligand during the synthesis of the CsPbX perovskite nanocrystals (NCs), yielding particles (5-12 nm) with tunable halide compositions that were homogeneously embedded in the GO-g-PAA matrix. The resulting NC-GO-g-PAA exhibits a higher photoluminescence quantum yield than previously reported encapsulated NCs while maintaining an easily tunable bandgap, allowing for emission spanning the visible spectrum. The NC-GO-g-PAA hybrid further self-assembles into well-defined nanorods upon solvent treatment. The resulting nanorod morphology imparts extraordinary chemical stability toward protic solvents such as methanol and water and much enhanced thermal stability. The introduction of barrier layers by embedding the perovskite NCs in the GO-g-PAA matrix, together with its unique assembly into nanorods, provides a novel strategy to afford robust perovskite emissive materials with environmental stability that may meet or exceed the requirement for optoelectronic applications.

Highly Luminescent Lead Halide Perovskite Quantum Dots in Hierarchical CaF2 Matrices with Enhanced Stability as Phosphors for White Light‐Emitting Diodes

“…It can be seen from the spectrum of the resulting device (Figure 4a), three discrete emission peaks located at 442, 520, and 621 nm were observed. And the as-prepared composites [28,36,37,40,42,46,47,51,53] could act as the green phosphors with decent performance. The selected triangle of blue, green, and red monochromatic light covers 130% of the National Television System Committee (NTSC) standard, which indicates great potential application in white backlights for LCDs.…”

“…[39][40][41][42] However, suffering from the poor thermal stability of organic components, polymers do not seem to be the best choice to protect PQDs. Especially, the obtained perovskite-polymer composites display waterproof property whereas the pristine perovskite materials are highly sensitive to humidity.…”

Unveiling the Photo‐ and Thermal‐Stability of Cesium Lead Halide Perovskite Nanocrystals

“…[15] This phase change is accelerated with harsh washing reagents and, with a more gentle washing strategy-using methyl acetate or MeOAc-CsPbI 3 , is stable in the γ (black) phase for over 2 months. Additionally, several groups have been developing methods of protecting the perovskite structure from moisture, including overlaying silicone resins, [60] preparing polymer or related composites, [61][62][63] and coating with zwitterion [64] or metal complexes. Park et al observe a 16-nm blue shift and eventual degradation in CsPbI 3 nanocrystals that were caused by the irreversible generation of surface defects during photoluminescence measurements.…”

Highly Efficient and Stable Inorganic Perovskite Quantum Dots by Embedding into a Polymer Matrix

“…Blending with polymer matrices has been developed in recent years to improve the stability of the perovskite QDs. Besides the enhanced stability, polymer matrices endow the perovskites with advantages in many aspects, such as water resistant ability, mechanical performance and enhanced luminescent properties ,,,. For example, recently, the perovskite film based on Polyvinylidene fluoride (PVDF) slight change even immersing them into water for 400 h .…”