Thermal analysis of white light-emitting diodes structures with hybrid quantum dots/phosphor layer

This study quantitatively analyzed the optical and thermal performances of remote quantum dots (QDs)-based white light-emitting diodes (QDs-WLEDs) with the same spectra power distribution (SPD) but reverse packaging structures. The output optical power and PL spectra were measured and analyzed by an integrating sphere system, and the temperature fields were simulated by combing optical measurement with thermal simulation, finally the temperature fields were validated by infrared thermal imager. It was found that when achieved identical SPD, the QDs-on-phosphor type achieved LE of 112.2 lm/W, while the phosphor-on-QDs type demonstrated lower LE of 101.4 lm/W. Moreover, the QDs-on-phosphor type generated less heat than that of another, consequently the highest temperature in the QDs-on-phosphor type was lower than another, and the temperature difference can reach 11.2°C at driving current of 160 mA. Therefore, the QDs-on-phosphor type is an optimal packaging architecture for higher optical efficiency and lower device temperature.