標題: | (Ca,Mg,Sr)(9)Y(PO4)(7):Eu2+,Mn2+: Phosphors for white-light near-UV LEDs through crystal field tuning and energy transfer |
作者: | Huang, Chien-Hao Wu, Pin-Jiun Lee, Jyh-Fu Chen, Teng-Ming 應用化學系 Department of Applied Chemistry |
公開日期: | 1-一月-2011 |
摘要: | Two series of single-composition (Ca,Mg,Sr)(9)Y(PO4)(7):Eu2+ and (Ca0.5Sr0.5)(9)Y(PO4)(7):Eu2+,Mn2+ phosphors were synthesized via high-temperature solid-state reactions. Their emission colors could be tuned from blue to green and eventually to red through tuning the crystal field splitting and energy transfer. On examining the Mn2+ concentration-dependent photoluminescence properties, we found that co-doping with Mn2+ would lead to a change in Eu2+/Eu3+ ratio. Moreover, an energy transfer from Eu2+ to Mn2+ occurs because of the spectral overlap between the emission band of Eu2+ and the excitation band of Mn2+. The resonance-type energy transfer via a dipole-quadrupole interaction mechanism was supported by decay lifetime data and the critical distance of energy transfer was calculated to be 11.09 angstrom A. A trichromatic white-light emitting diode was fabricated by integrating a 380 nm near-ultraviolet (n-UV) chip comprising yellow-emitting (Ca0.5Sr0.5)(9)Y (PO4)(7):0.007Eu(2+),0.02Mn(2+) and blue-emitting (Ca0.5Mg0.5)(9)Y(PO4)(7):0.007Eu(2+) phosphors into a single package. Such a composite device emitted white light with a correlated color temperature of 6303 K, a color rendering index of 87.4, and color coordinates (0.314, 0.348) close to those of ideal white light. The results suggest that a phosphor blend of (Ca0.5Sr0.5)(9)Y(PO4)(7):0.007Eu(2+), 0.02Mn(2+) and (Ca0.5Mg0.5)(9)Y(PO4)(7):0.007Eu(2+) is potentially useful for white n-UV light-emitting diodes (LEDs). |
URI: | http://dx.doi.org/10.1039/c1jm11018g http://hdl.handle.net/11536/150344 |
ISSN: | 0959-9428 |
DOI: | 10.1039/c1jm11018g |
期刊: | JOURNAL OF MATERIALS CHEMISTRY |
Volume: | 21 |
起始頁: | 10489 |
結束頁: | 10495 |
顯示於類別: | 期刊論文 |