Preparation And Luminescence Properties Of Aluminate Cyan Phosphors And Borate Near-infrared Phosphors For Full-spectrum LED Health Lighting

Sun-like full-spectrum healthy lighting is not only important for human physical and mental health,but also provides a high-quality light environment for people to study,work and live.However,there are"cyan gap"in the spectrum of traditional lighting sources and the lack of continuity in the spectrum from deep red light to near-infrared light.Aiming at the above problems,a series of new broadband cyan Ba_1-xAl₁₂O₁₉:x Ce³⁺and Ba_1-xAl₁₂O₁₉:x Eu²⁺phosphors with adjustable luminescence color and performance were developed by high-temperature solid-phase method,and Sr₂Sc_1-xLi(B₄O₁₀):x Cr³⁺broadband near-infrared phosphors were developed by the same method.The phase analysis,particle morphology,element distribution,luminescence kinetics,steady-state spectrum,transient spectrum,and the local environment where the luminescence center is located were carried out on the sample,as well as the evaluation of its device application.The specific research results are as follows:1.Select BaAl₁₂O₁₉with multiple cation sites as the matrix material,and rare earth elements Ce³⁺and Eu²⁺ions with 4f-5d characteristic transitions as activators.The activators occupy different crystallographic lattice sites in the matrix,and the emission bands are superimposed to form broadband cyan emission.The experimental results show that:（1）Ba_1-xAl₁₂O₁₉:x Ce³⁺phosphor,under the excitation of near-ultraviolet light wavelength of 361 nm,exhibits cyan emission in the spectral range of 365-650 nm,the main peak is located at 450 nm,and its full width at half maximum is 120 nm.Combining Ba_0.95Al₁₂O₁₉:0.05Ce³⁺and commercial red phosphors to prepare simple two-color pc-WLEDs that can be excited by ultraviolet light chips（λex=365 nm）,and realize fully visible color rendering index and correlated color temperature tunable Spectral white light.（2）Ba_1-xAl₁₂O₁₉:x Eu²⁺phosphor,under the excitation of near-ultraviolet light wavelength of 380 nm,the emission spectrum covers the blue light to green light（390-650 nm）region,and the main peaks are located at 450 nm（blue light）and 515 nm（green light）.The fluorescence internal quantum efficiency is as high as 83%.By changing the excitation wavelength,the luminescence is shifted from blue light to cyan and green regions.Finally,two-color white light was obtained by encapsulation,and a full-spectrum white LED device with a lower color temperature CCT=3696 K and a higher color rendering index CRI（Ra=94）was obtained.BaAl₁₂O₁₉:Re^3/2+(Re=Ce³⁺,Eu²⁺)phosphors all successfully filled the"cyan gap".2.Sr₂ScLi(B₄O₁₀)pyroborate with octahedral environment was selected as the matrix material,and a new type of Sr₂Sc_1-xLi(B₄O₁₀):x Cr³⁺phosphors with broadband near-infrared emission was successfully developed by taking advantage of the characteristic that Cr³⁺can produce broadband near-infrared emission in the weak octahedral environment.The experimental results show that:under excitation at 473 nm and 621 nm,the phosphor exhibits near-infrared emission at 700-1100 nm with a peak position of 821 nm and a full width at half maximum of 172 nm.At 150℃,the overall luminescence intensity of the sample can still maintain about 46.5%of the initial luminescence intensity,with good thermal stability.The emission range of the phosphor can be well overlapped with the solar spectrum in the near-infrared region,indicating that the Sr₂Sc_1-xLi(B₄O₁₀):x Cr³⁺phosphor has potential application value in the field of full-spectrum health lighting.