Thermally stable Mn2+-activated zinc silicate nanophosphor for speedy recognition of high-contrast latent fingermarks

摘要

Crystalline divalent manganese-activated zinc orthosilicate (Zn2SiO4:Mn2+) nanophosphor has been synthesized via the solution-based sol-gel process. Structural, morphological, and photoluminescence (PL) properties were explored. X-ray diffraction pattern confirms the crystalline hexagonal structure of the single-phase Zn2SiO4 powder. The size and shape of Zn2SiO4 powder were analyzed using micrographs, which implies that the prepared phosphor particles are in the nano range. PL spectra have been recorded as a function of Mn2+ dopant concentration. A dominant green (similar to 526 nm) emission broad peak was observed owing to the characteristic (T-4(1)->(6)A(1)) transition of Mn2+ ion under UV/blue excitation. The green emission (similar to 526 nm) intensity depends upon the doping concentration of Mn2+ ion, and it is found to be optimum for 2.0 mol%, after that quenching phenomenon was registered. The CIE color coordinate of Zn2SiO4:Mn2+ lies in the bright green region under UV excitation with 94.3% color purity. Real-time experiments have been carried out for speedy development of high-contrast fingermarks using Zn2SiO4 nanophosphor on various porous and nonporous substrates.