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摘要
A new Eu2+ activated, G-type La2Si2O7 phosphor was synthesized successfully via a novel SiC-reduction route. The valence state of the Eu2+ ions was identified with XRD and XPS analysis and the luminescence spectrum presented Eu2+ broad bands. The G-La2Si2O7: Eu2+ (LPS: Eu2+) phosphor exhibited tunable emission colors depending on the excitation wavelength or the Eu concentration, enabling the production of white light. The color tunable property is ascribed to the component ratio of the two specific luminescent centers, Eu(1) and Eu(2). Eu2+ ions prefer to occupy the La3+ crystallographic sites selectively, which was identified by electron paramagnetic resonance (EPR) spectroscopy. Furthermore, the relative emission intensity of the phosphor at 100 degrees C and 160 degrees C can maintain 89% and 76% of the value measured at room temperature, which is much better than that of most of Eu2+ doped silicon oxides phosphors. The Eu(1) emission possesses a better fluorescence thermal stability than the Eu(2) emission, and an energy transition from Eu(1) to Eu(2) occurs. This better thermal stability and energy transition have been explained by the schematic configuration coordination. A w-LED device was fabricated by combining the prepared La2Si2O7: Eu2+ and commercial BaMgAl10O17: Eu2+ phosphors with a 365 nm n-UV chip. The w-LED device generates white light (color rendering index R-a = 93.9), and its CIE chromaticity coordinates and correlated color temperature (CCT) are (x, y) = (0.3429, 0.3523) and 5090 K, respectively. These results suggest that LPS: Eu2+ has a great potential for use in UV-LED-driven white emitting diodes.
- 出版日期2017-2-21
- 单位中国科学院上海硅酸盐研究所; 上海材料研究所; 中国科学院大学; 高性能陶瓷和超微结构国家重点实验室
