"Nano Synthesis and Characterization of Er3+, Ho3+ & Li+ Co-Doped, Er3+ & Li+ Co-Doped and Ho3+ & Li+ Co-Doped Lanthanum Borosilicate Luminescent Materials (LaBSiO5) by Sol-Gel Pyrolysis Method for forensic applications"

Abstract

ABSTRACT: In the present investigation, lanthanum borosilicate nano materials doped with Er3+ /Ho3+ co-doped with Li+ or both Er3+ & Ho3+ co-doped with Li+ are synthesized using sol-gel Pyrolysis method taking urea as an organic precursor. The samples are found to be phase Pure from the XRD data analysed using X ’pert high score software. All the samples are found to have single phase Stillwellite structure with hexagonal symmetry. The unit cell dimensions are a = b = 6.870, c = 6.6964, V=274.26 in accordance with P31 space group. From the SEM studies it is observed that the spherical agglomerated particles are formed. The agglomeration is found to be more in Er3+ /Ho3+ and Li+ Co-doped samples than in Er3+, Ho3+ and Li+ co-doped samples. The agglomerated particle size is found to be in the range of 0.25 µm to 0.80 µm. From the HRTEM selected area diffraction pattern studies and XRD using Debye Scherer formula, the crystallite sizes are calculated which showed the formation nano particles. The synthesized samples when exposed under long range UV lamp emitted in the blue to violet region and when exposed under short range UV lamp emitted in the orange red region. The photoluminescence spectra showed the presence of two different cationic sites and intensity of the spectra is found to be more in the Er 3+, Ho3+ and Li+ co-doped samples than in the Er3+ /Ho3+, Li+ co-doped samples indicating the emission from the co -dopants following the carrier energy transfer model. The finger prints recorded on different materials using the synthesized phosphors throw light on the usefulness of the phosphors for forensic latent finger print detection.