Mesoporous Trap of Molecular Sieves via Water-Selective Capture for Stable Perovskite Quantum Dots

Abstract

Attaining good stability while maintaining superior properties is one of the main requirements for the application of organic/inorganic halide perovskite CH3NH3PbBr3 quantum dots (QDs) in lighting and display devices. However, stability and surface defects of QDs have been negatively affected because of the presence of H2O in solvents and humidity in air. Herein, a facile strategy is proposed to synthesize colloidal QDs with long-term luminescent and high quantum yield (QY) (92.1%) at room temperature. Molecular sieves are used with a pore size of 3 angstrom to selectively induce adsorption and reflection according to the size of the diameter. H2O removal is facilitated by the addition of molecular sieves to a polar solvent, thereby generating dehydrated QDs. Contact angle measurement and surface energy calculation (Owen-Wendt method) of a thin film coated with the dehydrated QDs confirm hydrophobicity. Moreover, 30 days after coating thin films with pristine and dehydrated QDs, cracks are observed on the pristine QD-coated thin film surface due to the decomposition of QDs. This is a crack formed by the separation of the QD ligand and the perovskite decomposition. Furthermore, dehydrated QDs maintained a PL intensity of 83.7% after 30 days. The proposed synthesis method is effective for the rational design of high-quality QDs having high efficiency and long-term stability.