Combustion synthesis and characterization of blue long lasting phosphor CaAl2O4: Eu2+, Dy3+ and its novel application in latent fingerprint and lip mark detection

Abstract

This work investigates the structural, optical and photometric characterization of a Eu2+/Dy3+ doped calcium aluminates phosphor (CaAl2O4: Eu2+/Dy3+) for finger and lip print detections. Synthesis of CaAl2O4: Eu2+/Dy3+ (CAED) phosphors were carried out via a combustion synthesis method with urea as a fuel. Eu2+/Dy3+ doped CaAl2O4 phosphors have been studied with X-ray diffraction (XRD, Energy Dispersive X-Ray Spectroscopy Selected Area Diffraction (SAED) and High resolution Transmission Electron Microscope (HR-TEM). The XRD pattern shows that the synthesized Eu2+/Dy3+ doped CaAl2O4 phosphor have a single monoclinic structure and show that the addition of the dopant/co-dopants didn’t change the crystal structure. The formation of monoclinic phase was confirmed by the selected area diffraction pattern. The TEM micrograph displays the morphology of the synthesized Eu2+/Dy3+ doped CaAl2O4 phosphors as spherical particles with an average particle size of 33nm. The optical band gap was calculated using the diffuse reflectance for the synthesized nanophosphor powders. The photoluminescence emission spectra was recorded for the synthesized powder, with an excitation wavelength of 326nm and the major bands was recorded at 447nm corresponding to the blue color and two minor bands were recorded at 577nm and 616nm. To the best of our knowledge, this work is the first to show the use of CaAl2O4: Eu2+/Dy3+ nanophosphor in developing latent fingerprint and lip print effectively.