General Method for the Synthesis of Ultrastable Core/Shell Quantum Dots by Aluminum Doping

Abstract

Semiconductor quantum dots (QDs) have attracted extensive attention in various applications because of their unique optical and electronic properties. However, long-term photostability remains a challenge for their practical application. Here, we present a simple method to enhance the photostability of QDs against oxidation by doping aluminum into the shell of core/shell QDs. We demonstrate that Al in the coating shell can be oxidized to Al2O3, which can serve as a self-passivation layer on the surface of the core/shell QDs and effectively stop further photodegradation during long-term light irradiation. The prepared CdSe/CdS:Al QDs survived 24 h without significant degradation when they were subjected to intense illumination under LED light (450 nm, 0.35 W/cm(2)), whereas conventional CdSe/CdS QDs were bleached within 3 h.

Stability of Quantum Dots, Quantum Dot Films, and Quantum Dot Light‐Emitting Diodes for Display Applications

“…Oxide overcoating is an excellent way to protect QDs from water and oxygen, but careful control is required not to lose quantum yield and stability simultaneously . For example, In 2 O 3 overcoating enhanced the quantum yield of InP/ZnS QDs from 48% to 59% .…”

Pure Blue and Highly Luminescent Quantum‐Dot Light‐Emitting Diodes with Enhanced Electron Injection and Exciton Confinement via Partially Oxidized Aluminum Cathode

“…The chemical components of the graded core/shell ZnCdS/ZnS QDs were further confirmed by X‐ray photoelectron spectroscopy (XPS) measurement and Figure d exhibits core level of S 2p peaks in the XPS spectrum. After deconvolution calculation of the spectra, we can easily figure out the three peaks of 161.6, 162.1, and 162.8 eV, representing S atoms in ZnCdS, ZnS, and Octanethiol, respectively . Peaks corresponding to Zn 2p and Cd 3d can also be found in the XPS spectra as shown in Figure S1 (Supporting Information), and their peak positions are in good agreement with previous reports …”

Highly Luminescent and Ultrastable CsPbBr3 Perovskite Quantum Dots Incorporated into a Silica/Alumina Monolith

“…[7] Due to the very low diffusion rates of ions or atoms,oxides such as silica oxide (SiO 2 ), titanium oxide (TiO 2 ), alumina (Al 2 O 3 ), and zirconium oxide (ZrO 2 ), often are used as barrier materials to protect organic light-emitting diodes, phosphors,a nd metals from oxidations,c orrosions or other chemical attacks. [10] These findings naturally inspired us to think about the idea of SiO 2 /Al 2 O 3 binary coating for PQDs.Actually,the SiO 2 /Al 2 O 3 binary coating has been already proved of providing better protection than the individual coating, for various materials,s uch as steel, [11] graphite, [12] and laser anti-damage material. [9] Moreover,w ef ound that Al 2 O 3 passivation layer significantly improved the photostability and thermal stability of CdSe/CdS QDs.…”

“…[9] Moreover,w ef ound that Al 2 O 3 passivation layer significantly improved the photostability and thermal stability of CdSe/CdS QDs. [10] These findings naturally inspired us to think about the idea of SiO 2 /Al 2 O 3 binary coating for PQDs.Actually,the SiO 2 /Al 2 O 3 binary coating has been already proved of providing better protection than the individual coating, for various materials,s uch as steel, [11] graphite, [12] and laser anti-damage material. [13] This is possibly because the combination of SiO 2 and Al 2 O 3 decreases the pinhole defects of coating layers which often form in the individual coatings of SiO 2 or Al 2 O 3 ,a nd achieve very low permeabilities of water and oxygen.…”