Excitation-wavelength-dependent luminescence of Sr3P4O13:Eu3+ amber-emitting microphosphor for fluorescence latent fingerprint visualization

In this work, the feasibility of applying Sr 3 P 4 O 13 :Eu 3+ , a micron phosphor, to latent fingerprint visualization was explored and discussed. The preferential occupancy of Eu 3+ in the host lattice was analyzed based on the bond energy method. The excitation-wavelength-dependent luminescence properties of the phosphor were investigated through the photoluminescence emission and excitation spectra . The phosphor could be pumped effectively by deep ultraviolet and near ultraviolet. The luminescent color of the phosphor could be tuned from reddish orange (0.6025, 0.3939) to yellow (0.4729, 0.5031) with the change of excitation wavelength from 254 nm to 394 nm. The multilevel features of the phosphor-attached latent fingerprint could be identified clearly in deep ultraviolet. The high color contrast between ridge and valley lines provided a splendid condition for the observation. Moreover, the effect of the phosphor used on different substrates for latent fingerprint visualization was explored. All the results reveal that the phosphor was a good potential choice for latent fingerprint visualization.