High Thermal Performance and Reliability of Quantum-Dot-Based Light-Emitting Diodes With Watt-Level Injection Power

Abstract

Quantum dots (QDs) attract great attention due to their narrow emission spectra, providing excellent light quality for light-emitting diodes (LEDs) in illumination and display applications. However, their low thermal reliability suppresses the commercial applications of QD-based LEDs. In this report, it is the first time that we realize high thermal performance and reliability QD-based LEDs with watt-level injection power. The QD-on-reflector (QOR) structure is proposed to separate QDs from the heat source of chips, and targeted cooling for QD/polymer composites is achieved with an Al-based reflector. Compared with the reference [conventional QD-on-chip (QOC) structures], the QOR-LEDs exhibit higher total radiant power/luminous flux and color consistency. Most important, the QOR-LED has a steady temperature of only approximately 50 °C in QD/polymer composites, which is 90 °C lower than the reference and is the reported lowest temperature for QD-based LEDs. The working-aging test shows that the luminous flux maintenance (LFM) factor of the QOR-LED is 92.2%, whereas that of the reference is only 21.2% after aging for 20 min. This corresponds to a lifetime of 88.5 times longer than that of the QOC-LED at the same LFM of 20%. Consequently, the QOR structure can provide better optical performance, superior thermal performance, and longer lifetime for QD-based LEDs.