Reduced Working Temperature of Quantum Dots-Light-Emitting Diodes Optimized by Quantum Dots at Silica-on-Chip Structure

Abstract

White light-emitting diodes (WLEDs) composed of blue LED chip, yellow phosphor, and red quantum dots (QDs) are considered as a potential alternative for next-generation artificial light source with their high luminous efficiency (LE) and color-rendering index (CRI) while QDs' poor temperature stability and the incompatibility of QDs/silicone severely hinder the wide utilization of QDs-WLEDs. To relieve this, here we proposed a separated QDs@silica nanoparticles (QSNs)/phosphor structure, which composed of a QSNs-on-chip layer with a yellow phosphor layer above. A silica shell was coated onto the QDs surface to solve the compatibility problem between QDs and silicone. With CRI > 92 and R9 > 90, the newly proposed QSNs-based WLEDs present 16.7% higher LE and lower QDs working temperature over conventional mixed type WLEDs. The reduction of QDs' temperature can reach 11.5 °C, 21.3 °C, and 30.3 °C at driving current of 80 mA, 200 mA, and 300 mA, respectively.