Efficient luminescence of doped bismuth oxychloride nanophosphors and its surfaces prompted applications

The materials which cater to excellent sensitivity, superior contrast, inexpensive and eco-friendly are in urgent need for law enforcement applications. To overcome these barriers, red-emitting BiOCl:Eu3+ (1–9 ​mol %) nanophosphors were prepared by the self-ignited combustion method. The powdered x-ray diffraction profiles were well indexed to a tetragonal phase of BiOCl without any traces of impurities. The 2-dimensional agglomerated irregular flake-like structures without any clear boundaries were clearly revealed. The photoluminescence emission spectra consist of distinct sharp peaks at ∼ 536, 555, 594, 621, 652 and 698 ​nm, which were owing to 5D1→7F1, 5D1→7F2, 5D0→7F1, 5D0→7F2, 5D0→7F3 and 5D0→7F4 transitions of Eu3+ ions, respectively. A noticeable increment in the photoluminescence emission intensity with an increase of activator Eu3+ concentration up to 5 ​mol % and later it diminished. The dipole-dipole interaction was mainly responsible for observed concentration quenching. The estimated commission international de l'eclairage coordinates are found in orange-red as well as a red region in the diagram, indicating that the emission color can be tuned by varying activator Eu3+ ions concentration. The fingerprints developed using optimized nanophosphor showed distinctive papillary ridge particulars and hence specifies the higher sensitivity without any background hindrance. The aged fingerprints developed on the glass surface retained their ridge characteristics up to level 2 even after being stored for 180 days. The developed anti-counterfeiting labels can only be decoded under ultra-violet 365 ​nm light with clear intense red color. The obtained results clearly demonstrated the effectiveness of the fluorescence nanophosphor for latent fingerprint visualization and data encryption applications. [Display omitted] •Red emitting BiOCl:Eu3+ (1–9 ​mol %) phosphors were prepared by solution combustion route.•A new fluorescence based platform has been setup for visualization of latent fingerprints by powder dusting method.•Developed latent fingerprints shows superior contrast, sensitivity, efficiency, selectivity and negligible background hindrance.•Developed anti-counterfeiting labels can only be decoded under ultra-violet 365 ​nm light.