Synthesis And Properties Of Y₂O₃: Eu³⁺ And New Phosphors For Lamps

has been used as commercial red phosphor in fluorescent lamps for its high efficiency, intensity and other advantages. But, the sintered temperature of Y2O3:Eu3+is very high, which lead to the high cost of the phosphor. So we must cut down the price by reducing the calcination temperature. However, the emission intensity decreases at the same time. So the key point to solve this problem is improving the luminescence intensity of Y2O3:Eu3+ at relatively low synthesis temperature. In this work, the main purpose is to improve the luminescence properties of Y2O3:Eu3+ red phosphor.In order to reduce the calcination temperature, we use some low melting point materials as flux which added to the Y2O3:Eu3+ phosphor. The addition of flux in Y2O3:Eu3+ can decrease the sintering temperature. In this study, H3BO3,Li2CO3, Na2CO3, K2CO3, Li2B4O7, Na2B4O7, K3PO4, LiF, CaF2, and BaF2 assist as flux in Y2O3:Eu3+ phosphors to increase the luminescence intensity. The results show that the sample incorporated 2 wt% of K2CO3 and Li2B4O7 in Y2O3:Eu3+ demonstrates the highest emission intensity. In addition, Y2O3:Eu3+ phosphor coated with B2O3 can increase the luminous intensity, for which the reaction temperature is low, and it is easy to operate. And the results show that the best sample is the Y2O3:Eu3+phosphor with 0.04 wt% of H3BO3 added to.At the same time, fluorescent lamps contain mercury which is not friendly to the environment, so replacing mercury lamp becomes more and more important. And the mercury-free fluorescent lamp and white LED are novel light source with environmental-friendly excitation sources. The excitation sources of the mercury-free fluorescent uses Xe rare gas with 147 and 172 nm. The LED chip with emission wavelength around 350～420 nm has been wildly used. The researches on new phosphors with excitation wavelength located in this range are necessary.In this paper, we also studied the luminescence properties of Ca3Y2(Si3O9)2:Eu3+ red phosphor upon UV and VUV excitation. The UV excitation spectrum shows that Ca3Y2(Si3O9)2:u3+ can absorb the 254 nm excitation light and convert to red emission. The emission spectra of Ca3Y2(Si3O9)2:Eu3+ under different excitation wavelengths show different emission spectra profiles, indicating that Ca3Y2(Si3O9)2 matrix has at least two different sites. The selective excitation has been observed. The luminescent properties of the new Ca3Y2(Si3O9)2:Tb3+ green phosphor under UV and VUV excitation have also been studied. The emission spectra show the strongest emission peak is located at 546 nm for green emission.Combining tricolor phosphors is a way to form a white light source, and using a single white phosphor is another way. Based on this, new white phosphors Ca3Y2(Si3O9)2:Dy3+, NaCaPO4:Dy3+ and LaSrAl3O7:Ce3+, Tb3+ have been studied by UV and VUV light excitation.