Enhancing thermal and optical properties for liquid quantum-dot-based self-loop system toward laser illumination by controlling the layer location

White light sources based on laser diodes are considered to be the next-generation light sources owing to their high luminous efficiency, high luminous flux, and excellent directivity. Quantum dots (QDs) are new fluorescent materials that have been widely used in lighting and displays. However, when used for high-power illumination, QDs excitation and emission are accompanied by obvious attenuation problems owing to their reabsorption effect and low stability in high temperature environment. To solve these problems, this study proposes three types of QD-based self-loop systems for laser illumination and analyzes their thermal and optical properties. White light is obtained by exciting red and green QDs using a blue laser. The three types of self-loop converters are green-QD-front type (structure I), red-QD-front type (structure II), and hybrid type (structure III). The average temperatures of the excitation region of structures I and II were maintained at approximately 37.3 degrees C and 37.0 degrees C, respectively, which were both lower than that of the hybrid structure (46.7 degrees C). The radiation flux of structure I only attenuated by 15.6% after laser irradiation for 120 min. Furthermore, the shift in color coordinates was the smallest. When the laser driving current was changed from 500 mA to 1500 mA, the correlated color temperature (CCT) drift was only 474 K. We believe that these results will provide guidelines for QD-based laser-driven illumination.