We have prepared a new phosphor Dy-substituted La2W2O9. The La2-xDyxW2O9 exhibited a yellow-white luminescence consisting of sharp emission peaks assigned to 4F9/2→ 6H15/2, 4F9/2→ 6H13/2, 4F9/2→ 6H11/2, and 4F9/2→ 6H9/2 transitions in Dy3+ ions, respectively. The maximum internal quantum efficiency was 21.3% at x = 0.05 under the 387 nm excitation light. The white LED was fabricated by using a UV LED at 385 nm and the La2-xDyxW2O9 (x = 0.05) phosphor (Dy-WLED). The plant cultivation experiments for Chlorella photosynthetic growth was carried out by using the Dy-WLED and a reference commercial white LED, and the reduction of the Chlorella growth was confirmed in the Dy-WLED.

Keywords: Photoluminescence, La2W2O9, Dy3+, Plant habitat-concious LEDs.