Nanostructured Stannic Oxides for White Light Emitting Diodes Provides Authentication for Latent Fingerprints Visualization under Diverse Environmental Conditions

SnO2:Eu3+ nanopowders were prepared by biofriendly hydrothermal method using Aloe Vera gel as a biotemplate. Prepared samples were characterized for their structural, morphological, and optical properties using powder X-ray diffraction, scanning/transmission electron microscopies, and diffused reflectance spectroscopy. Morphology shows the layered structures with sharp edges confirms the system with better surface area along with sticky nature. Energy band gap of the samples varies from 3.44 to 3.74 eV. Photoluminescence results showed the dipolar–dipolar interactions and led to red light emission when excited with 392 nm excitation wavelength. Optimized compounds were explored for their feasibility to visualize well-preserved latent fingerprints on the various types of surfaces. Visualized fingerprints show the details of third-level ridges, bifurcations, and pores with high selectivity, better contrast, and without background hindrance. Clarity of developed fingerprints was also examined under aquatic e...