Optical performance enhancement of light-emitting diodes with quantum dots through new remote type structure

Nowadays colloidal quantum dots (QDs) have been developed as a promising light-converting material for light-emitting diodes (LEDs). However, QDs-based LEDs always show saturation effect at high forward current. In this paper, a new remote packaging structure was proposed to reduce the saturation effect and utilize the QDs fully. The comparison of optical performance between proposed remote structure and current structures, flat structure and air-gap with regular lens was conducted through experiments. The luminous efficiencies of air-gap structure with regular lens and proposed remote structure are over 22% higher than flat structure at the driving current of 20mA. With the current increasing from 20 to 800mA, the luminous efficiencies of flat structure and air-gap structure with regular lens decrease by 66.5% and 61.5%, respectively. While the proposed remote structure shows the luminous efficiency decrease of 37.7%. Therefore, at the driving current of 800mA, compared to current structures, the proposed remote structure increases the luminous flux by 70.5% and 50.1%, respectively. The experimental results demonstrate that the new packaging structure have large advantages in terms of the luminous efficiency and the stability.