Synthesis and spectroscopic analysis of Eu3+-doped tungsten bronze Sr5YTi3Nb7O30 phosphors for w-LED and visualization of latent fingerprint

Abstract

A series of novel Sr5YTi3Nb7O30: x Eu 3+ ( x = 0.05–0.40) red-emitting phosphors were firstly synthesized using the high-temperature solid-state method. The X-ray diffraction (XRD) patterns demonstrate that the phosphors are pure phase with the space group P 4 bm of tetragonal system. Under the 395 nm excitation wavelength, the red emission of Sr5YTi3Nb7O30:Eu 3+ phosphor is considered to be dominated by the 5 D 0 → 7 F 2 transition at 613 nm. The asymmetry ratios (R/O) of Sr5YTi3Nb7O30: x Eu 3+ ( x = 0.05–0.40) phosphors are identified as 2.64–2.78, which contribute to the high color purity (99.5%–99.8%). The phosphor has good thermal stability with 0.17 eV of activation energy. The Commission International de L'Eclairage (CIE) coordinates of the w-LED nearly overlap with the standard white light (0.333, 0.333), the R a is as high as 90. Meanwhile, the features of fingerprint are simultaneously distinguished at three levels on aluminum foil by Sr5YTi3Nb7O30:0.30Eu 3+ phosphor. In addition, the latent fingerprint on various nonporous substrates (stainless steel, glass, and plastic surfaces) were identified. In summary, the phosphor is feasible to apply in the w-LEDs and latent fingerprint detection.