Study On Single-matrix White Light Phosphor For LED Driven By UV Chip

Compared with traditional lighting sources,white LEDs have higher luminous efficiency,longer service life and lower power consumption,and are non-polluting to the environment and easy to recycle.With the strong support of the government and continuous research and development by researchers,white LED will completely replace incandescent and fluorescent lights as a new generation of lighting energy.At present,LEDs of blue light chips are harmful to human eyes,and the color purity of white light is low,which is difficult to meet the requirements of high color purity lighting.The white light obtained by three-color phosphors excited by ultraviolet chips effectively solves this problem.The prepared LED has high color purity,but the white LEDs of three-color phosphors excited by ultraviolet also have some disadvantages,such as complex color ratio control,low color stability caused by self-absorption and different light decay of each phosphor.LED devices employing a single white-light-emitting substrate as a phosphor can avoid these problems.A single white light phosphor can be divided into inorganic materials,organic materials,and organic-inorganic hybrid materials.However,inorganic phosphor materials often require complex manufacturing processes and very high synthetic temperatures,which results in high cost of preparation.To solve this problem,a series of organic materials and organic-inorganic hybrid materials used as single luminescent substrate of white LED were synthesized by a simple solution method.The effects of reaction conditions on its structure,luminescent properties and stability were studied by means of NMR,XRD and fluorescence spectrum.The main contents of this paper are as follows:(1)By using phenyl maleimide with yellow light,bisindolylmaleimide derivative with green light,and non-emissive spirobifluorene as the core,and blue light-emitting polyfluorene as the arm,two single white light star-like polymers TC-F-02 and TC-F-03 were synthesized through Suzuki reaction coupling reaction.By changing the ratio of different central cores and their content,the partial energy transfer from the polyfluorene chain to the central cores is realized.And the star-like polymers were encapsulated by silica gel to give a composite film material with excellent white light properties and the CIE of(0.33,0.34),(0.33,0.37).(2)A series of white-light organic-inorganic hybrid perovskites P_xM_yC_1.5B_2.5 were synthesized by using two-dimensional phenethylamine perovskite as the host and Mn²⁺as the dopant.By changing the content of Mn²⁺,the light color and quantum yield of perovskites can be controlled.When the ratio of Mn/Pb is 1:1,the quantum yield of P_0.5M_0.5C_1.5B_2.5is 31.9%,which is 3.3 times higher than that of the undoped sample.The CIE of P_0.5M_0.5C_1.5B_2.5 is(0.33,0.27).Perovskite were blended with silica gel to fabricate composite materials,which shows excellent stability under water,heat and ultraviolet.(3)The above materials were coated on 380nm UV chips to fabricate LED devices.It was found that each device showed excellent white light performance.Among them,the color rendering index(CRI)of perovskite LED devices can reach 90.4,accompanied by the color temperature of 3080k,and the CIE of(0.41,0.36),which is a very excellent warm white LED device.