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

Pure and chromium(III) doped nanosized Al2(WO4)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 Al2(WO4)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.

► Nanosized Al2(WO4)3 can be synthesized by simple co-precipitation method.
► Decrease of the particle size leads to weak structural changes.
► Chromium(III) ions occupy sites of intermediate crystal field strength.
► The electron–phonon coupling slightly decreases with decreasing particle size.