Photoluminescence-based nanomaterial sensors doped with rare-earth elements have a potential for use in sensitive, portable, and low-cost detectors. The oxide with the formula XY2ZO5 has potential for fluorescence applications because of its orthorhombic structure, stable physical and chemical properties, and high thermal stability. In this study, BaY2ZnO5 phosphors with various concentrations of Tm3+ and urea ions were synthesized at 1200 oC for 8 h in air by the sol-gel method. The characteristics of the phosphor powders were analyzed by field-emission scanning electron microscopy, X-ray diffraction (XRD), and photoluminescence spectroscopy. The diffraction peaks of phosphors with Tm3+ ion doping concentrations from 0 to 5 mol% and urea additions from 1 to 50 wt% are attributed to the orthorhombic BaY2ZnO5 structure examined by XRD analysis. When the Tm3+ ion concentration is 2 mol%, the maximum emission intensity of the 1D2→3F4 transition can be obtained, which then decreases with increasing Tm3+ ion concentration. Concentration quenching occurs when the Tm3+ ion concentration is above 2 mol%. For BaY2ZnO5 phosphors prepared by doping with Tm3+ ions and adding urea, excitation with an emission wavelength of 457 nm yields the color tone in the vivid blue region.