Targeting cooling for quantum dots by 57.3°C with air-bubbles-assembled three-dimensional hexagonal boron nitride heat dissipation networks

The non-radiative electron transitions of Quantum dots (QDs) in White light-emitting diodes (WLEDs) not only generates thermal phonons with temperature rise but also degrades their photonic properties. These nanoscale heat sources are usually embedded in low-thermal-conductivity polymer matrix, which is difficult for building efficient heat dissipation pathways without sacrificing the optical performance simultaneously. Herein, we reported an air-bubbles-assembly strategy to construct three-dimensional (3D) thermal dissipation network inside the QDs-WLEDs. Owing to the lateral expulsion of massive microscale air-bubbles, an interconnected hexagonal boron nitride (hBN) network was established under an extremely low hBN loading of 2.74 wt%. With this efficient 3D/hBN network, the highest working temperature of QDs was dramatically decreased by 57.3°C at 700 mA. More than that, the 3D/hBN-WLEDs also show high luminous efficacy of 84.6 lm/W as well as superior color rendering index of Ra = 94.1 and R9 = 93.8, which are comparable to those of traditional WLEDs. The proposed strategy is expected to pave a new door for targeting cooling QDs and other photoluminescent nanoparticles at high-power applications.