Synthesis and Luminescence Properties of Intensely Red-Emitting M[sub 5]Eu(WO[sub 4])[sub 4−x](MoO[sub 4])[sub x] (M=Li, Na, K) Phosphors

We have investigated the luminescence of a series of phosphors and discovered that exhibit the most intense red emission among the three investigated. Powder X-ray diffraction investigations show that a complete solid solution can be formed in the indicated composition range. The effect of chemical compositions on the luminescence properties of has been investigated and discussed. The Commission International de l'Eclairage chromaticity coordinates were found to be (0.66,0.33) for , which reaches the same level as that of the commodity. The color-rendering index ( a) of a typical white-light–light emitting diode (WL-LED) based on was found to be 82.3, higher than that (i.e., ) obtained for the WL-LED fabricated using the commodity of when the WL-LEDs were operated at a forward-bias current of at room temperature. is therefore suggested to be a potential red-emitting phosphor for WL-LED.