Ultrasound induced synthesis of dual phased hierarchical ZrO2:Eu3+ architectures: Fluorescent based sensor for rapid visualization of latent fingerprints

Red emitting ZrO2:Eu3+ (1-7 mol %) nanophosphors were fabricated via ultrasonication route with Aloe Vera gel as a bio-surfactant. The sonication time engineered both the crystal structure and morphology of the prepared nanophosphor: shorter sonication time leads to the synthesis of tetragonal phase, while - longer sonication time favors the formation of cubic ZrO2 phase. A plausible growth mechanism of the architectures that implies aggregation via oriented attachment followed by an Ostwald ripening was proposed. The photoluminescence results showed the characteristic emission peaks of Eu3+ ions at (similar to) 591 nm (D-5(0) > F-7(1)), 606 nm (D-5(0) > F-7(2)), 661 nm (D-5(0) -> F-7(3)) and 712 nm (D-5(0) -> F-7(4)). The photometric results clearly evident that the nanophosphors emit pure red color with high purity, which signify its use as a warm red component in WLEDs applications. The - powder dusting strategy was followed for the visualization of sweat latent fingerprints using optimized ZrO2:Eu3+(5 mol %) nanophosphor on many surfaces. Most essential type 1-3 ridge characteristics were clearly revealed with high sensitivity, selectivity and low background hindrance. The adopted method was simple and environment friendly for sweat fingerprint development, and promising outlook in criminal investigation and forensic science.