A Cycling Cooling System Of Liquid Quantum Dots For Laser Illumination Applications

The unique photoelectric properties of quantum dots have relevant applications in the fields of bioimaging,medical treatment,sensing,batteries,display and lighting.At present,quantum dots are mainly used in low power applications,because quantum dots are prone to fluorescence quenching due to temperature rise.The poor thermal stability of quantum dots restricts the development of high-power applications of quantum dots.To solve these problems,a novel liquid quantum dot circulating cooling light converter was designed for high-power laser lighting.The temperature of liquid quantum dots excited by high-power laser was controlled by two kinds of flow cycles: external pressure driving and internal phase transition driving.The stable application of liquid quantum dots in high power laser illumination was realized.The performance of the laser-excited liquid quantum dot flow cycle system was studied for the optical,chromaticity and temperature parameters of the laser lighting system.The main research contents are as follows:(1)Performance influence of external pressure driving cycle system of laser excited liquid quantum dots: The liquid quantum dots solution was driven to circulate by a peristaltic pump.And the Peltier cooler cooled the liquid quantum dots in the circulation pipeline.In this way,the external pressure driven circulating cooling system of liquid quantum dots was established.The effect of factors such as the temperature of the solution,the flow rate of the solution,and the laser drive power on the optical and thermal performance of laser illumination was systematically studied and analyzed.The influence of external pressure driving cycle on the photothermal properties of liquid quantum dots excited by laser was investigated.(2)Research on the performance of the driving cycle system of the internal phase transition of liquid quantum dots excited by laser: Flowing liquid quantum dots can effectively resist the quenching phenomenon of quantum dots caused by high power laser.The driving cycle mode of liquid quantum dots was optimized.The driving cycle mode of liquid quantum dots was optimized,and the heat dissipation mechanism of internal phase transition driving cycle was proposed.The heat which generated by the non-radiative recombination of quantum dots excited by laser drove the solution to cycle spontaneously to achieve the purpose of heat dissipation.A quartz glass tube with closed vapor-liquid cycle was designed for the internal phase transition driving cycle of liquid quantum dots.The internal phase transition driving cycle laser illumination system of liquid quantum dots was built.The photothermal properties of liquid quantum dots under the internal phase transition driving cycle and static closed state were studied.(3)Research on the performance of laser illumination system of liquid quantum dots: The influence of the free-form surface shape of the closed vapor-liquid cycle quartz glass tube on the photochromic performance of the laser lighting system was investigated by simulation.The mechanism of the influence of the free surface shape of quartz glass tube on the laser quantum dot lighting system was proposed.Based on the simulation results,the closed vapor-liquid cycle quartz glass tube was optimized,and the double channel square closed vapor-liquid cycle quartz glass tube and single channel square closed vapor-liquid cycle quartz glass tube were designed for white light lighting.The photothermal effects of layered and hybrid quantum dot packaging methods on laser white light illumination system were investigated.According to the emission spectrum,radiation flux,light efficiency and chromaticity indexes,the performance differences of the laser drive current on different packaging structures were further analyzed.Finally,the best packaging method based on the liquid quantum dot internal driving cycle white light illumination was obtained.