Highly Efficient and Thermally Stable QD-LEDs Based on Quantum Dots-SiO₂-BN Nanoplate Assemblies

Abstract

Silica encapsulation effectively elevates the resistance of quantum dots (QDs) against water and oxygen. However, QDs-SiO 2 composites present low thermal conductivity and strong thermal accumulation, leading to considerable fluorescence quenching of QDs in optoelectronic devices at high power. Here, a sandwich structural QDs-SiO 2 -BN nanoplate assembly material (QDs-SiO 2 -BNAs) is developed to reduce the thermal quenching and enhance the stability of QDs in LEDs. The QDs-SiO 2 -BNAs is fabricated by embedding QDs-SiO 2 into the interlayer of layer-by-layer assembled BN nanoplates, and the BN nanoplates are pretreated by SiO 2 encapsulation to strengthen the interaction with QDs-SiO 2 . This assembly structure endows the QDs with fast heat dissipation and double surface protection against air. The medium power QDs-converted LEDs (QD-LEDs) fabricated by direct on-chip packaging of the QDs-SiO 2 -BNAs gain 44.2 °C temperature reduction at 0.5 W in comparison with conventional QD-LEDs. After aging, the resulting QD-LEDs present degradation of only 1.2% under sustained driving for 250 h. The QD-LEDs also pass the 1 week reliability test at 85 °C/85% RH with <±0.01 shift of the color coordinates, demonstrating the profound potential of the QDs-SiO 2 -BNAs in LED lighting and display applications.

Efficiency Enhancement of Quantum-Dot-Converted LEDs by 0D–2D Hybrid Scatterers

“…The thickness and refractive index of the BN scatterers are set as 35 nm and 1.73, according to the report and the product information. 47 The changes in refractive indices of the three scatterers (SiO 2 , BN, and SiO 2 −BN) within the ambiance of neat silicone gel, with a refractive index of n = 1.53, are shown in Figure S4. The electric field distributions of the three scatterers within the silicone gel ambiance under the illumination of two plane lights incident along the +x direction with the wavelength of 450 nm (emitting light of the LED chip) and 640 nm (emitting light of the QDs) were calculated, respectively.…”

51.3: Stable Quantum Dot Nanocomposites for Display Application

“…We further demonstrate the fabrication of stable all-inorganic QDs composites by integrating the characteristic of high thermal conductivity into the air-barrier encapsulations. 4 We show that the solid QDs composite can be handled like classical phosphors for directly on-chip packaging in medium and high-power LEDs. The prepared QD-LEDs display ultimate color quality and high thermal-and photo-stability.…”

Luminescence Enhancement, Encapsulation, and Patterning of Quantum Dots Toward Display Applications

“…developed a sandwiched QD‐SiO 2 ‐BN nanoplate by embedding the QDs in BN layers with modified SiO 2 surface to strengthen the interaction, as illustrated in Figure 11f. [ 99 ] The BN nanoplates reduced the thermal quenching of the QDs and enhanced their air‐barrier property together with the SiO 2 thin film. Silica/alumina particles were also used to encapsulate the PQDs, and PQD monolith was obtained that could be ground into powder.…”

“…Copyright 2019, Elsevier B.V. f) QD-SiO 2 -BN nanoplate assembly and the aging performance of QD-LED. Reproduced with permission [99]. Copyright 2019, American Chemical Society.…”