Preparation Of High-performance Solar And Thermal Composite Materials For Application Research On White LED

With the development of material and the innovation of semiconductor manufacture technology,the rapid development of white LEDs is more and more significant.White LEDs have tended to replace the traditional lighting,owing to their long life,non-polluting,low-power performance.LEDs will open a new era in "green lighting".The paper first briefly introduces the concept and characteristics of LEDs. Currently,white LEDs are confronted with two problems of low luminescent efficiency and bad heat dissipation.To solve the above problems,the investigation in novel luminescent and thermal composite materials is performed in this paper.1,Water-soluble cadmium selenide(CdSe) QDs by employing CdCl₂ and NaHSe as precursors were synthesized in alkaline aqueous solution by ultrasonic method.Their structure and optical properties were studied by photoluminescence spectroscopy,UV-Vis spectra and transmission electron microscope.The result showed that the size of CdSe QDs was about 2-3nm and their optical properties such as the wavelength and intensity of photominescence were dependent on the reaction time,the growth temperature,the pH value,the concentration of stabilizing agent and reactants etc.Eventually quantum dots were doped into the LED light-emitting phosphors and further study is to be carried out.2,Another aspect is the heat dissipation.In general,the cooler the environment,the higher an LED's light output will be.Higher temperatures generally reduce light output and LED's lifetime.If the heat within the junction is dissipated by convection and conduction,the actual lifetime and the efficiency of LED would be increased.Nano-composite materials with high thermal conductivity have been explored to enhance the LED performance.