Targeting Cooling for Quantum Dots in White QDs-LEDs by Hexagonal Boron Nitride Platelets with Electrostatic Bonding

Although quantum dots (QDs) show excellent advantages in flexible wavelength-tuning and high color rendering capability in white light-emitting diodes (WLEDs) lighting and display applications, the less-than-one quantum efficiency inevitably gives rise to a non-negligible heat generation problem, which induces high-temperature quenching issues of QDs and severely hinders their potential applications. Efficient heat dissipation for these nanoscale QDs is challenging since these nanoparticle heat sources are usually embedded in a low-thermal conductivity polymer matrix. In this work, this problem is attempted by targeting cooling of the QDs in the silicone matrix by electrostatically bonding the hexagonal boron nitride (hBN) platelets onto QDs without sacrificing the optical performance of WLEDs. The red-emissive QDs/hBN composites are mixed with yellow-emissive phosphor to fabricate QDs/hBN-WLEDs. Due to the effective heat transfer channels established by the QDs/hBN in the silicone, the heat could be dissipated efficiently to ambient air, and the working temperature of WLEDs is reduced by 22.7 degrees C at 300 mA. The QDs/hBN-WLEDs still maintain a high luminous efficiency of 108.5 lm W-1 and a high color rendering index of Ra > 95, R9 > 90, showing that the present strategy can improve heat dissipation without sacrificing the optical performance.