Photoluminescence study of Yb3+/Er3+ co-doped Sb2O3-WO3-Li2O (SWL) ceramic phosphor for fingerprint detection in forensic science and security writing

The article reports the development of invisible cryptography writing and latent fingerprint detection techniques using upconversion emission of rare earth doped ceramic for the application in forensic science. The upconversion (UC) emission studies on Yb³⁺/Er+³⁺ co-doped Sb₂O₃-WO₃-Li₂O (SWL) ceramics under 980 nm laser excitation has been done. Due to its intense green and red visible emission, the ceramic finds a great application in developing latent fingermark detection using powder dusting technique. In addition to fingerprint detection, the present ceramic is a promising candidate for coding cyphers in invisible manner. An observed comparison between UV vs. NIR excited fingerprint images shows that fingerprint images exposed by NIR excitation have more clear edges than the UV excitations. Hence the current upconversion emission studies on the present ceramic samples reveal its potential application in forensic science, security writing and cryptography information (cypher).