Effect of Washing Solvents on the Properties of Air-Synthesized Perovskite CsPbBr₃ Quantum Dots for Quantum Dot-Based Light-Emitting Devices

Abstract

In order to improve the stability and cost of perovskite CsPbBr3 and establish a preparation process for quantum dot materials with excellent luminescence properties, CsPbBr3 quantum dots were synthesized by the hot injection method and the ice bath method in air ambient. Then, a proprietary purification system was used to improve the properties of the quantum dots and prepare high-quality perovskite quantum dot films. Optimal material and light characteristics were exhibited with ethyl acetate:hexane as the purification solvent. In the solution form, the photoluminescence wavelength could be maintained at 508 nm with almost no shift compared with other conditions, and the quantum yield could reach 99%; however, superior performance was obtained in the thin-film form, which exhibited little to no shift in the photoluminescence wavelength and, surprisingly, achieved a quantum yield of 91.6% with a narrow PL emission with a full width at half-maximum of 28 nm. In addition, exceptional thin-film uniformity was observed from scanning electron microscopy image analyses. The CsPbBr3 quantum dot light-emitting diode purified with ethyl acetate:hexane demonstrated an open-circuit voltage of 4 V, a maximum luminous brightness of 488 cd m-2 , and a maximum external quantum efficiency of 0.14%.

A Facile Centrifuge Coating Method for High-Performance CsPbBr3 Compact and Crack-Free Nanocrystal Thin Film Photodetector

“…Usually after fabrication, a purification procedure of the QD crude solution is required. Typically, a polar solvent such as ethyl acetate is used to promote the precipitation during centrifugal purification [30]. After that, the QD was redispersed in toluene nonpolar solvent for long-time storage.…”

Influence of Binary Ligands in Designing Cesium Lead Halide (CsPbX3, X = Cl, Br, I) Perovskite Nanocrystals-Oleic Acid and Oleylamine

“…Purification by suitable solvents greatly assists in controlling ligand density in Cs LHP NCs. For example, purification using an ethyl acetate/hexane solvent mixture was found to precisely regulate OA/OAm ligand density in Cs LHP NCs with excellent PL properties [118][119][120]. When the prepared crude solid Cs LHP NCs undergo multiple purification cycles, the detachment of ligands substantially impacts the colloidal stability as well as the lifetime and PLQY of Cs LHP NCs.…”

Zeolite A-Coated Mn-Doped Perovskite Quantum Dots Prepared by Vapor Deposition Crystallization for Reduction of CO2

“…Therefore, surface encapsulation has emerged as the main strategy to improve the stability of perovskite QDs. As shown in Table , introducing long-chain and zwitterionic ligands to passivate the surface of QDs has acquired research focus to improve the stability of QDs for their application in electrical injection devices. − However, the ligand is highly dynamically bound to the surface of the QDs and has limited resistance to external environments (such as light and heat) . Compared with molecular-state ligands, polymer/inorganic coatings have higher stability to regulate the dynamic binding. − However, most polymers have a low thermal stability, , and with a core–shell structure, it is necessary to consider whether the lattices of the core and shell match .…”