Physico-chemical nanomaterials science

Synthesis, morphology and luminescence properties of Pr3+-doped BiPO4 nanopowders
Chornii V.1,2, Boyko V.1, Bychkov K.2, Nedilko S.G.2, Slobodyanik M.2, Terebilenko K.2, Gomenyuk O.3, Sheludko V.3
1 National University of Life and Environmental Sciences of Ukraine, Geroiv Oborony st.,15, Kyiv-03041, Ukraine. 
E-mail: vchornii@gmail.com 
2 Taras Shevchenko National University of Kyiv, Volodymyrska st., 64/13, Kyiv-01601, Ukraine.
3 Oleksandr Dovzhenko Hlukhiv National Pedagogical University, Kyievo-Moskovs’ka st., 24, Hlukhiv-41400, Ukraine.

Effective transformation of electric energy in lighting sources is the technical task of a high priority. At present time the most effective lighting devices are light emitting diodes (LEDs). Typical LEDs consist of semiconductor chip covered by phosphor material and the last one greatly determines spectral characteristics of a device and efficiency of electricity-to-light conversion. The commercially available red phosphors can be considered as ones that have lower efficiency in comparison to blue, green or yellow phosphors. In the same time Pr3+ doped oxide materials including phosphates, aluminates or borates have been widely used as a red emitting phosphor exhibiting relatively strong absorption in the near ultraviolet range of the light and intense red luminescent emission of good color purity
In this work the results of synthesis procedure for BiPO4:Pr polycrystalline samples as well as their characterization by X-ray diffraction, scanning electron microscopy and luminescent spectroscopy are presented. It is found that doping leads to phase transformation from high temperature monoclinic to low temperature monoclinic phase of BiPO4. Scanning electron microscopy studies show that depending on praseodymium content particles either prism-like or rod-like with 100-200 nm sizes are present. At room temperature and under excitation into absorption band of praseodymium ions the studied samples revealed intensive orange/red luminescence. The mechanisms of photoluminescence excitation and emission are discussed together with data on structure and morphology of the samples.