Study on Reabsorption Properties of Quantum Dot Color Convertors for Light-Emitting Diode Packaging

Quantum dot (QD) attracts great attention in light-emitting diode (LED) packaging for high-quality light sources, while it leads to low light efficiency due to the significantly high reabsorption loss between QDs. Accordingly, we experimentally study the reabsorption properties of QD color convertors (QCCs) for LED packaging considering various thicknesses and concentrations under different injection current. The results indicate the QCC configuration with a small thickness and large concentration can have the same absorption ability for chip light as that with the opposite configuration, resulting in the same QD light proportion. However, the QCC configuration having smaller thickness is more useful to decrease the reabsorption loss, leading to higher radiant power (an increase of larger than 37.2%). Moreover, it is essential to gain a high radiant power of QD light with small reabsorption loss, which can be realized by combining QCCs with a low QD content and a source with a large injection current. Based on this simple and effective approach, a conversion loss smaller than 20%, close to their quantum yield, can be achieved, which is approximately four times smaller than that gained by QCCs with a high QD content. However, it introduces additional radiant power of chip light, suppressing further improvement in the QD light proportion. Much work is still required to make full use of the redundant chip light. This study provides a better understanding of the reabsorption properties of QCCs and can significantly accelerate their applications in illumination and display applications.