Abstract

Recently, many Eu3 -doped tungstate systems have been reported for possible application in photonics. However, some of these materials require high amounts of europium or extensive time and energy consumption to obtain high red emission. Also, it is notable that due to the price and critical resource of rare earth elements, it would be better to reduce the amount of these elements for an economic, energetic and environmental friendly synthesis procedure. Alkali-metal ions (Li, Na, and K) codoped Eu-emitting phosphors can be an alternative for these conventional materials. Small amount of these ions can act as a charge compensator, as a sensitizer changing the CT band of the host lattice (O2- - W6 ), enhance the intensity of Eu3 red emission and improve the color purity of the material. So, this approach can reduce the amount of Eu needed to produce better and more efficient phosphors. α-(Ag2-3x-yEuxLiy)WO4 (x = 0 and 1; y = 0-3 mol%) nanocrystals were efficiently synthesized by the coprecipitation method without any further heat treatment. X-ray powder diffraction patterns show all peaks can be indexed to the pure α-Ag2WO4 orthorhombic phase (Fig. 1). It was also observed most defined and sharp Raman modes and luminescence peaks for the samples with Li (Fig. 2). This can be explained because of Li are smaller than Ag allowing a better insertion of Eu3 into the matrix relaxing the host lattice and contributing for the charge balance of the system. These results show new phosphor for luminescent application