Spectroscopic investigation of ultrasound assisted sonochemical synthesis of BiOCl: Dy3+ nanophosphors for latent fingerprints visualization

Abstract A series of Dy3+ (1-9 mol %) doped BiOCl NPs were fabricated via ultrasound assisted sonochemical route using Aloe Vera (A.V.) gel as a bio-surfactant. Intense and sharp powder x-ray diffraction profiles confirm the matlockite-type tetragonal structure of BiOCl. The morphology of the nanophosphor was engineered by varying various experimental parameters, namely ultrasound irradiation time, pH level and A.V. gel concentration. The photoluminescence emission spectra of the prepared nanophosphor comprised of several intense peaks at ∼ 457, 549 and 614 nm, which are ascribed to 4F9/2→6H15/2 (Blue), 4F9/2→6H13/2 (Green) and 4F9/2→6H11/2 (Red) transitions of Dy3+ ions, respectively. The Judd–Ofelt intensity parameters Ωt (t= 2, 4) and other important radiative properties, such as total radiative transition probability, radiative life time and branching ratio of Dy3+ ions in the BiOCl were exploited using photoluminescent emission spectra. The photometric properties of the nanophosphors exhibit pure cool white light emission, which validate the potential applications of synthesized nanophosphor in phosphor converted white light emitting diodes. The optimized BiOCl:Dy3+ (5 mol %) nanophosphor was utilized as a powder dusting material to visualize LFPs on diverse surfaces. The stable optical properties and nano-regime of the nanophosphor permitted high resolution imaging enabling level I-III ridge arrangements details can be obtained. Therefore, the prepared nanophosphor has great potential for application in individual recognition.