Preparation And Properties Of Novel Ultraviolet Excited Tri-color Phosphors For LED

White LED?Light Emitting Diode?has excellent physical and chemical properties,such as high light efficiency,no radiation,small size,long life,low power consumption,etc.,can effectively convert electrical energy into light energy,showing huge application potential and value.However,the current commercial white LEDs also have some deficiencies,such as blue LED chips+YAG:Ce³⁺(Y₃Al₅O₁₂:Ce³⁺)yellow phosphors because of the lack of red light components,resulting in low color rendering index and high color temperature.In order to improve the luminous performance of existing commercial LEDs,the combination of near-ultraviolet LED chips to excite red,green,and blue primary phosphors has become a current research hotspot.Therefore,it is very important to study new and efficient phosphors for near ultraviolet LED.?1?The luminescence characteristics of a novel silicate matrix-based KBaY_1-xSi₂O₇:xRE³⁺?RE=Dy,Eu?color temperature adjustable white phosphor was prepared and studied.When the single-doped Dy³⁺and Eu³⁺concentrations are x=0.05 and x=0.10,respectively,the phosphor has the best luminous intensity,emitting white light and red light,respectively.Under the excitation of near ultraviolet light at 394 nm,Dy³⁺can effectively transfer the excitation energy from the ⁴F_9/2 energy level to the ⁵D_J energy level of Eu³⁺ions.KBaY_1-xSi₂O₇:xDy³⁺,yEu³⁺phosphors obtain warm white light.?2?The luminescence properties of a new type of Ca_1-xNaB₅O₉:xRE³⁺?RE=Dy,Eu,Tb?phosphor based on borate matrix were prepared and studied.Under the excitation of near-ultraviolet light at a certain wavelength,the single-doped Dy³⁺,Eu³⁺,and Tb³⁺samples emit white light,red light,and green light,respectively.Under the excitation of 377 nm,Ca_1-x-yNaB₅O₉:xTb³⁺,yEu³⁺phosphors due to the energy transfer from Tb³⁺to Eu³⁺,Tb³⁺can effectively transfer the excitation energy through the ⁷F₆ energy level to the ⁵D_J energy level of Eu³⁺ions.As the concentration of Eu³⁺increases,Tb³⁺The fluorescence lifetime gradually decreases.Under the excitation of 393 nm,Ca_1-x-yNaB₅O₉:xDy³⁺,yEu³⁺phosphors due to the energy transfer from Dy³⁺to Eu³⁺,the fluorescence lifetime of Dy³⁺will decrease with the increase of Eu³⁺ion concentration.?3?The Ba₃YB₃O₉ red phosphor co-doped with Eu³⁺/Bi³⁺was prepared and studied.By analyzing the excitation spectrum of the phosphor,it is known that the sample can be efficiently excited by near ultraviolet light at 393 nm.Due to the ⁵D₀-⁷F₂ transition of Eu³⁺,the emission spectrum shows a strong characteristic peak at 613 nm.Bi³⁺doping can effectively improve the luminous intensity and color purity of Eu³⁺.Among them,Ba₃Y_0.87B₃O₉:0.12Eu³⁺,0.01Bi³⁺samples have the best color purity,and the CIE chromaticity coordinates are?0.6433,0.3563?.?4?The luminescent properties of the tunable Ba_3-x-yB₆Si₂O₁₆:xTb³⁺,yEu³⁺series phosphors based on borosilicate matrix were prepared and studied.Under the excitation of 377nm,the characteristic transitions of Tb³⁺and Eu³⁺ions are observed in the emission spectra of Ba_3-x-yB₆Si₂O₁₆:xTb³⁺,yEu³⁺.The excitation spectra of Tb³⁺and Eu³⁺overlap in the excitation spectrum,so there will be an energy transfer relationship of Tb³⁺?Eu³⁺.By changing the concentration of Eu³⁺,a color-adjustable phosphor is obtained.As can be seen from the chromaticity diagram,the emission color can be adjusted from green to yellow and red.?5?La_1-x-ySiBO₅:xTb³⁺,yEu³⁺color tunable phosphors based on borosilicate matrix were prepared and studied.Under excitation of 369 nm,Eu³⁺red light?580⁶50 nm?and Tb³⁺yellow-green light?480⁵00 nm,530⁵60 nm?were produced.Due to the energy transfer of Tb³⁺?Eu³⁺,the color can be adjusted by changing the concentration of Eu³⁺.From the chromaticity diagram,it can be seen that the emission color changes from green to yellow and red.