Design,Preparation And Luminescence Properties Study Of Non-rare-earth(NRE=VO₄,Bi³⁺) Activated Broadband Phosphors

To address the problems of insufficient spectral width and missing components of the mainstream white light illumination technology in the market,this paper selects non-rare earth VO₄ and Bi³⁺without visible excitation as activators and synthesizes a series of phosphors with broadband emission,K₂Ba Ca（PO₄）_2-x（VO₄）_x（0≤x≤0.25）and Ba₂Y₅B_5-xP_xO₁₇,:0.5%Bi³⁺（0≤x≤1）by high-temperature solid-phase method.The crystal structure,particle morphology,elemental distribution,steady-state spectra,transient spectra,luminescence property,luminescence kinetic processes,luminescence thermal stability,and device packaging of the phosphors were studied in detail to improve the lighting quality of white light and provide design ideas for the development of non-rare earth broadband phosphors.The specific research results are as follows.（1）In order to enrich the number and type of VO₄-activated phosphors and improve their thermal stability,this experiment proposes the construction of luminescent centers VO₄ in thermally stable phosphates.The formation of VO₄ centers was successfully constructed by replacing P⁵⁺in K₂Ba Ca（PO₄）₂（KBCP）substrates with V⁵⁺,which has a high electron localization property.In the K₂Ba Ca（PO₄）_2-x（VO₄）_x(KBCP_2-xV_x)compound,the presence of the VO₄ group greatly enhanced the absorption efficiency of near-UV light,producing a broadband yellow emission centered at 568 nm with a full width at half maximum（FWHM）of 213 nm.At 150°C,the KBCP_1.8V_0.2 sample showed excellent thermal stability with an emission loss of only 10%,exceeding the previously reported performance of VO₄-activated vanadate phosphors.The white light emitting diodes（WLEDs）obtained using KBCP_1.8V_0.2 phosphors showed high color rendering index（87.3-93.4）and a wide range of correlated color temperatures（4357-6510 K）（2）Single-component,single-activator Bi³⁺-activated full visible spectrum Ba₂Y₅B_5-xP_xO₁₇:0.5%Bi³⁺（0≤x≤1）white-light phosphors were synthesized using an anionic group co-replacement strategy.Under 360 nm excitation,the corresponding luminescence color was coordinated from blue to white with increasing PO₄ content.This is attributed to the substitution of the three-dimensional structure PO₄ tetrahedral group for the triangular planar structure of BO₃,which leads to a more distorted lattice and affects the local structure of Ba²⁺ions in this structure,allowing Bi³⁺to occupy the otherwise unoccupiable Ba1 and Ba2 lattice sites,thus inducing a new emission peak at 600 nm and finally obtaining white light emission covering the full visible spectrum.The experimental analysis proves that the anionic group co-substitution strategy PO₄-BO₃ can provide a new path for the occupation of the activator in the matrix lattice and effectively broaden the emission spectrum of the phosphor.In addition,the phosphor also achieves controlled color emission from blue to white under 280-350 nm excitation due to the complex energy transfer between different luminescent centers.Most importantly,the x=0.8 sample achieves an ultra-wide emission with a half-height width of 280 nm covering the entire visible spectrum under 340 nm excitation,which is similar to that of sunlight.The quantum efficiency of the phosphor was as high as 65.8%,showing its great potential for applications in health lighting light sources.