Research On Quantum Dots Light-emitting Diodes For Lighting And Communication

With the rapid development of wireless communication technology,wireless spectrum resources have become increasingly tight.Visible light communication?VLC?as a supplement to wireless communication technology has attracted the attention and research of governments and researchers from various countries since its introduction.Compared with the traditional wireless microwave communication,visible light communication technology has the advantages of abundant spectrum resources,no electromagnetic pollution,and safety,and has shown broad application prospects in many fields such as indoor positioning,safety communication,and intelligent transportation.GaN-based white light-emitting diodes?LEDs?based on third-generation semiconductor materials have been used in our daily life as a new generation of lighting sources.Compared with traditional lighting such as incandescent lamps and fluorescent lamps,nitrogen Gallium-based white LEDs have the advantages of high luminous efficiency,long life and low power consumption.In addition,it has the characteristics of high-speed modulation,which can realize the wireless optical transmission of data while illuminating,which further promotes the development and application of visible light communication technology.At present,the main research content of visible light communication is how to improve the modulation bandwidth and stability of the entire optical communication system.Among them,the quality of the white light source will directly affect the performance of the entire system.Although the GaN-based white LED has many advantages and can be used as a light source of visible light communication technology,the modulation bandwidth of the white LED is only about 3 MHz.Aiming at this problem,this paper has carried out detailed research in theory and experiment.The white LED made of colloidal quantum dot material has taken into account both lighting and communication needs.The main research contents of this paper are as follows:?1?CdSe-based core-shell quantum dots and CsPb(Br_1.65/I_1.35)perovskite colloidal quantum dots were synthesized and characterized.Using optical simulation software,the optical and structural characteristics of quantum dot phosphor white LEDs were analyzed and simulated.According to the simulation results,corresponding quantum dot white LEDs were prepared,and the optical characteristics and stability of quantum dot white LEDs were analyzed.?2?According to the luminescence principle of phosphor white LED,the theoretical model between modulation bandwidth and fluorescence lifetime is established,and the correctness of the theoretical model is verified through experiments.The transmitter and receiver modules of the visible light communication system are designed,and the quantum dot white LED is used as the light source of the visible light communication system.The relationship between the bias voltage and bit error rate of the quantum dot white LED and the communication distance and bit error rate is tested.In summary,the innovation of this article is:by simulating the luminescence characteristics of phosphor white LEDs,using quantum dots with short fluorescent life and high luminous efficiency as phosphor materials,white LEDs prepared by the LED meet the requirements of the lumen efficiency,The color temperature requirement also meets the high bandwidth requirement of VLC;for the first time,the theoretical model between the modulation bandwidth and the fluorescence lifetime is established based on the principle of phosphor white LED.