Size-Dependent Metal-Embedded Packaging for Performance Enhancement in Quantum-Dot-Converted Light-Emitting Diodes

A colloidal quantum dot (CQD) package with convex-surface solder reflectors of various diameters exhibited more favorable thermal characteristics and optical reliability performance than did the traditional in-chip package. The results indicated that solder balls provided a direct cooling path on the top of the LED chip to accelerate heat dissipation, and blue photons were reflected by the ball surfaces to enhance their recycling. The areal temperature results decreased from 88.4 °C (in-chip) to < 70 °C (solder ball) at a current of 180 mA. By contrast, continuous aging tests indicated that the devices with metal structures exhibited lifetimes four to six times longer than that of the in-chip device. The metal embedded structures not only provided a relatively low operating temperature but also extended the operating time of the packaged CQDs. This study pushes the envelope in the endeavor to integrate high-thermal-conductivity components into quantum dot photonic devices.