Thermally stable Mn ²⁺ ‐activated zinc silicate nanophosphor for speedy recognition of high‐contrast latent fingermarks

Abstract Crystalline divalent manganese‐activated zinc orthosilicate (Zn ₂ SiO ₄ :Mn ²⁺ ) 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 Zn ₂ SiO ₄ powder. The size and shape of Zn ₂ SiO ₄ 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 Mn ²⁺ dopant concentration. A dominant green (∼526 nm) emission broad peak was observed owing to the characteristic ( ⁴ T ₁ → ⁶ A ₁ ) transition of Mn ²⁺ ion under UV/blue excitation. The green emission (∼526 nm) intensity depends upon the doping concentration of Mn ²⁺ ion, and it is found to be optimum for 2.0 mol%, after that quenching phenomenon was registered. The CIE color coordinate of Zn ₂ SiO ₄ :Mn ²⁺ 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 Zn ₂ SiO ₄ nanophosphor on various porous and nonporous substrates.