Combustion synthesis was used to obtain nanocrystalline Y(2-x-y)TmxYbyO3 blue-emitting phosphors. From X-ray diffraction (XRD) it was determined that the powders in the as-synthesized state were in a state of high strain. Upon thermal treatment, the strain in the lattice decreased, which resulted in an improvement in the photoluminescence emission intensity of these phosphors. Fourier-transform infrared spectrometry analysis showed that there is a negligible difference in the absorbed impurities with heat-treatment temperature and time. Hence, it was concluded that the surface impurities do not play a role in the increase in luminescence intensity of these phosphors. The optimum activator concentrations were determined to be approximately x = 0.02 and y = 0.01.