Exploring innovative applications of Sr2MgSi2O7:Fe3+ luminescent system in surface-triggered fingerprint divergence and cheiloscopy screening

In this study, we employ a cost-effective combustion method to synthesize (1–11 mol %) Fe3+ doped Sr2MgSi2O7 nanophosphors (SMSO NPs) and conduct a comprehensive investigation into their structural and luminescent properties. The impact of iron concentration on the structural and optical characteristics is thoroughly analysed, revealing a tetragonal crystal structure with space group P-421m through Rietveld refinement and X-ray Diffraction (XRD) patterns. Scanning electron microscopy showcases the random dispersion of agglomerated particles with non-uniform dimensionality. Energy Dispersive X-ray analysis (EDS) assesses the nominal composition of Sr, Mg, Si, Fe, and O, while X-ray Photon Spectroscopy (XPS) confirms the direct incorporation of Fe3+ ions into the SMSO lattice. Photoluminescence (PL) emission spectra exhibit a deep red emission band at 718 nm. The residual luminescence intensity of SMSO:7Fe3+ at 200 °C is 91 %. Under 365 nm UV light, the optimized SMSO:7Fe3+ NPs displays easily identifiable levels I-III fingerprints (FPs) features with good resolution and contrast. The resilient luminescence and nano-regime of the phosphor reveal well-defined type I–V groove patterns in latent lip prints (LLPs) on various non-porous surfaces, unaffected by background interference or colour distraction. This study highlights SMSO:7Fe3+ NPs as a promising option for individualizing and detecting latent fingerprints (LFPs) and lip prints (LPs). [Display omitted] •Intense red emitting Sr2MgSi2O7:Fe3+ (1–11 mol %) NPs are prepared using solution combustion method.•The phosphors showed red luminescence at 718 nm when stimulated by 345 nm.•Developed latent fingerprints and lip prints show superior contrast, sensitivity, selectivity and negligible background hindrance.•The overall results clearly indicated that Sr2MgSi2O7:Fe3+ NPs open up a new avenue in advanced forensic applications.