Optical and phonon properties of nanocrystalline Al2(WO4)3 doped with chromium(III) prepared by co-precipitation method

Abstract Pure and chromium(III) doped nanosized Al 2 (WO 4 ) 3 was prepared by co-precipitation method. X-ray, transmission electron microscopy, vibrational, absorption and luminescence studies of the obtained nanoparticles are reported. The particle size of the obtained samples ranged from about 20 nm to a few hundreds of nm. Raman and IR studies showed that vibrational properties have been modified in comparison with the bulk material, indicating that with decreasing particle size some weak structural changes are induced in Al 2 (WO 4 ) 3 . The luminescence revealed that the prepared materials have similar properties as the bulk material and chromium(III) ions occupy sites of intermediate crystal field strength. Nevertheless, the obtained results indicate that the electron–phonon coupling slightly decreases with decreasing particle size.