| Popis: |
New red tungstates phosphors, Na 5 La 1− x Ln x (WO 4 ) 4 (Ln = Eu, Sm) and Na 5 Eu 1− x Sm x (WO 4 ) 4 , were prepared by solid-state reaction technique. And their structure and photo-luminescent properties were investigated. The introduction of Sm 3+ broadened the excitation band around 400 nm of the phosphors, and strengthened the red emission. And the possible energy transfer process from Sm 3+ to Eu 3+ is discussed. The single red LED was fabricated by combining InGaN chip with Na 5 Eu 0.94 Sm 0.06 (WO 4 ) 4 as red phosphor, intense red light can be observed by naked eyes. Then the phosphor Na 5 Eu 0.94 Sm 0.06 (WO 4 ) 4 may be a good candidate for red component of near-UV InGaN-based W-LEDs, because of efficient red-emitting with broadened absorption around 400 nm and appropriate CIE chromaticity coordinates ( x = 0.65, y = 0.34). |
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