| Nowadays in China, the problem of energy is an important problem without a doubt. As new type of lighting technology which waste less energy than traditional ones, the WLED is attracted widespread attention at home and abroad. The white light is the color of the light composite made of a variety of needs, but in current WLED Market is lack of efficient red phosphor which can improve the optical properties of WLED, So to find a good red phosphor is very pivotal.In this paper, we used the traditional high-temperature solid-phase method and the two-step reaction method before and after to prepare series of Ca2La8Si6O26:xEu3+ red phosphor, and we explored the best parameters for the preparation of these two methods. In using conventional solid phase prepared Ca2La8Si6O26:xEu3+ phosphor process, this paper explored the best parameters using a single variable and orthogonal method from the aspects of the calcination temperature, holding time, cooling rate, the typeand the amount of flux, Eu3 + doping concentration respectively. The results show that under calcination conditions of temperature of 1400 ℃ incubated 4h, and controls the cooling rate at a high temperature furnace for 20 ℃ / min to obtain excellent performance may be synthesized phosphor sample; when in use the total mass ratio of 2% Li2CO3 + BaF2 flux and BaF2/Li2CO3=1:3, the Ca2La8Si6O26:xEu3+ phosphor can be prepared in the best performance; and when the light emitting center of Eu3 + doping concentration is x = 0.4, the sample has the strongestemission peak performance for concentration quenching, and finally found the calcination temperature and doping concentration of Eu3 + phosphor have greater impact on this phosphors.The best preparation ofCa2(La0.6Eu0.4)8Si6O26sampleusing the above parameters and analyze it, found its XRD patterns of samples and standards Ca2La8Si6O26 card(No.29-0337) the degree of agreement, explain the main crystalline phase consisting Ca2La8Si6O26; its product particle uniformity is good, theproduct particle hasregular shape and high integrity, the sample at a wavelength under 614nm(red) to monitor light conditions, 394nm(near ultraviolet) and 464nm(blue) are present at this strong excitation peak, indicating that this kind phosphor has great value in current LED market.For Ca2(La0.6Eu0.4)8Si6O26 best phosphor samples were using different types of alkaline earth metal cations substitution matrixcations and adding co-doped different types of ions for modification, the results show that when using the Ca2+ which has the smaller radius as the cation of the R2(La0.6Eu0.4)8Si6O26(R=Ca、Sr、Ba), the phosphor has the higher fluorescence; were added content of 0.05 Gd3 + and Bi3 + able to Ca2(La0.6Eu0.4)8Si6O26 phosphor role played sensitizer so as to enhance its fluorescence properties.Finally, a two-step reaction prepared Ca2La8Si6O26:xEu3+ phosphor under conditions of 1200 ℃ heat 3h prepared Ca2La8Si6O26 precursor and Ca2Eu8Si6O26 precursor, then mix them for the second firing, the results showed that in 1300℃ as a secondary sintering temperature and hold for 4h,and Eu3 + doping concentration is 0.3,the Ca2(La0.7Eu0.3)8Si6O26 has the best performance; finally the optimum samples in these two methods were compared, found that the crystalline aspects ofperformance and particle morphology of these two samples are close but the fluorescence performance of sample which is prepared in two-step method is slightly better than conventional solid-phase method. |
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