The effective fingerprint detection application using Gd2Ti2O7:Eu3+ nanophosphors

Highlights: • Gd₂Ti₂O₇:Eu³⁺ nanophosphors have been synthesized by using a citrate sol-gel method. • The structural, morphological and optical properties of Gd₂Ti₂O₇:Eu³⁺ nanophosphors were analyzed. • The detection results (level 1–3) of latent fingerprints developed by Gd₂Ti₂O₇:Eu³⁺ nanophosphors were investigated. Nanostructure phosphors have been used for optical device and identification of individual fingerprint information. Herein, we report the orange-red emitting Eu³⁺ ions activated cubic Gd₂Ti₂O₇ nanophosphors through a citrate sol-gel method. The crystal structure, morphology, optical band gap, luminescent properties, Judd-Ofelt and fingerprint were analyzed. The crystal structure of Gd₂Ti₂O₇:Eu³⁺ nanophosphors confirmed the cubic phase. The morphology of nanophosphors exhibited the irregular particle shape with tens-nanometer size. The PL intensity was increased with rising Eu³⁺ ion concentration, indicating an optimum concentration of 0.09 mol. The emission spectra appeared an orange-red emission (⁵D₀→⁷F₁) with the CIE coordinates of (x = 0.615, y = 0.384). The latent fingerprints developed on various substrate have been exhibited excellent visualization and sensitivity. Based on these results, Gd₂Ti₂O₇:Eu³⁺ nanophosphors are promising applications such as luminescent materials for luminescent devices and latent fingerprint.