Red Photoluminescence from Bi³⁺and the Influence of the Oxygen-Vacancy Perturbation in ScVO₄: A Combined Experimental and Theoretical Study

Abstract

We report on a red-emitting ScVO4:Bi3+ phosphor which does not show excitation at energies below 2.88 eV (430 nm). X-ray diffraction, time-resolved, and quantitative photoluminescence (PL) spectroscopy were employed to characterize relations between crystal structure and luminescence properties of the material. Results show that incorporation of Bi3+ renders the blue photoemission of blank ScVO4 to red. Dynamic luminescence analysis between 10 and 300 K reveals a complicated dependence of energy transfer from VO4 3– groups to Bi3+ ions and population redistribution of 3P1 and 3P0 of Bi3+ on temperature. This reflects in distinct changes in the luminescence decay functions. That is, a dramatic decrease of Bi3+ luminescence lifetime occurs from hundreds to only several microseconds. Density functional theory is employed to reveal how the unusual red Bi3+ luminescence comes, and results indicate that the perturbation of oxygen vacancies which is generated readily when bismuth precipitates into ScVO4 is the reason for the experimental observation, although the vacancies themselves do not show photoluminescence. Upon excitations at 330 and 380 nm, internal quantum efficiencies can be up to ∼56% and ∼47%, respectively, implying the potential application of the red phosphor in warm-white-light-emitting diodes. As a proof of concept, an exemplary device was developed by combining the present phosphor with an ultraviolet-light-emitting diode and a commercial phosphor (Ba, Eu)MgAl10O17:Mn. We obtain a color rendering index (CRI) of >90 and a color temperature of ∼4306 K at chromaticity (0.3744, 0.3991).

Site Occupancy Preference, Enhancement Mechanism, and Thermal Resistance of Mn4+ Red Luminescence in Sr4Al14O25: Mn4+ for Warm WLEDs

“…The red phosphor should be excitable by blue light (for instance with a wavelength between 450 nm to 480 nm) and not by green light. 1,[6][7][8][9] In this way the composite system can efficiently avoid the reabsorption of the as-generated white light. This idea has stimulated research on red phosphors activated by rare earths, with outstanding candidates being divalent europium-doped (oxy)nitrides.…”

Color - Tunable Phosphors in Weberite Type System, La3 SbO7 :Bi3+ , Eu3+ for Near-UV LED Applications

“…have reported the greenish‐yellow luminescence of Bi 3+ ions in lanthanide vanadate phosphors. Whereas red luminescence in scandium vanadates and blue emission in calcium antimonates were reported by Kang et al . and Yao et al .…”

Optical properties of orthovanadates, and periodates studied from first principles theory

“…The electronic structure of zircon-type orthovanadates under pressure was investigated and it was reported that cation substitution influence the electronic states [8]. Red shift of the vanadate band gap observed with the cation substitution, further results in decrease of the band gap as observed with the Bi doping in these orthovanadates [9,10]. Errandonea et al [2] studied the transition pressure of ABO 4 orthovanadates, and found it to be in the range of 7e8 GPa independent of cation size, and also observed two transitions i) zircon / scheelite ii) scheelite / monazite but in the case of ScVO 4 only first transition is observed, whereas in the case of EuVO 4 , LuVO 4 , both the transitions are observed.…”