Silica encapsulated ZnO quantum dot-phosphor nanocomposites: Sol-gel preparation and white light-emitting device application

Abstract

ZnO quantum dots (QDs) as an eco-friendly and low-cost material has bright fluorescence, which makes it promising material for healthy lighting and displaying. However, the low fluorescence efficiency and poor stability of ZnO QDs impede their applications in lighting application. In this work, silica encapsulated ZnO QD-phosphors nanocomposites (ZSPN) have been prepared through a sol-gel synthesis process, where yellow-emitting ZnO QDs and blue-emitting BaMgAl 10 O 17 :Eu 2+ are employed as the luminescence cores and silica as link between two luminescence materials. Tunable photoluminescence of ZSPN and the white light emission have been achieved through changing mass ratio of both of ZnO QDs and commercial phosphors. The PLQY of the ZSPN can reach 63.7% and they can maintain high luminous intensity even the ambient temperature up to 110 • C and after 35 h of UV irradiation. In addition, they can keep stable for 40 days. By coating the ZSPN phosphors onto a ultraviolet chip, WLEDs with luminous efficiency of 73.6 lm/W and the color coordinate, correlated color temperature, and color rendering index can reach (0.32, 0.34), 5580 K, and 87, respectively, indicating the bright prospect of the ZSPN phosphors used in healthy lighting.

Zinc oxide light-emitting diodes: a review

“…Very recently, a Chinese research collaboration has made use of silica-containing ZnO quantum dots to fabricate LED phosphors. 166 They used solgel techniques to prepare yellow-emitting silica-encapsulated ZnO quantum dots. The powdered material was then mixed with blue-emitting BaMgAl 10 O 17 ∶Eu 2þ phosphor.…”

Single-component electroluminescent white light-emitting diodes based on zinc oxide quantum dots with high color rendition and tunable correlated color temperature

“…17 To date, most of the ZnO-WLEDs were realized on the basis of ZnO-QD phosphors that were usually integrated with an ultraviolet or blue excitation source. 25–28 The success of ZnO-QD phosphor WLEDs demonstrated that the ZnO-QD phosphor is a promising material for application in WLEDs. However, the potential risk of backlight leakage in the phosphor WLEDs greatly reduces their practical value because the ultraviolet or blue backlight is harmful to human eyes.…”

Water-Dispersed Perovskite Nanocube@SiO2-C18-PC Core–Shell Nanoparticles for Cell Imaging

“…In addition to TiO 2 encapsulation, SiO 2 is often used to coat fluorescent nanoparticles for its well-known advantages, such as easy preparation, low toxicity, and excellent light transparency. Additionally, inert SiO 2 layers are able to passivate material surfaces and restrict the rotation and vibration of the bonds, thus coating of SiO 2 can effectively improve the stability and quantum yield of fluorescent nanoparticles. , Hu et al prepared monodisperse PQDs/SiO 2 Janus nanoparticles using an interfacial synthesis method and used the stabilized PQDs for fabricating white light LED devices . In the PQDs/SiO 2 Janus particles, single PQD nanocubes were protected by SiO 2 only at one side; thus, it was still difficult to apply them in aqueous environments usually met in bioimaging and chemical sensing.…”