Luminescence of a novel double-perovskite Sr2InSbO6:Eu3+ orange-red-emitting phosphor for white LEDs and visualization of latent fingerprints

Eu3+-activated Sr2InSbO6 (SISO) orange-red-emitting double-perovskite antimonate phosphors were realized. The emission spectrum of SISO:Eu3+ sample exhibited a strong orange-red emission band at 594 nm under 395 nm excitation. Judd-Ofelt theory analysis indicated the Eu3+ ions were in the symmetrical environment of SISO host lattice. The fabricated white light-emitting diode presents a high Ra and a good CCT. For the visualization of latent fingerprints (LFPs), the hydrophilic SISO:Eu3+ phosphor was converted into hydrophobic SISO:Eu3+@OA phosphor by coating oleic acid (OA). The SISO:Eu3+@OA phosphor could show reliable level 1–3 fluorescent images of LFPs with high contrast and resolution. The LFPs still exhibited the excellent visualization on the various substrates (glass, aluminum foil, stainless steel, compact disk, student card, and so on). These results indicate the SISO:Eu3+ products have great potential applications for WLEDs and visualization of LFPs.