Synthesis and Characterization of Nb₂O₅:La³⁺,Eu³⁺Phosphors Obtained by the Non-Hydrolytic Sol-Gel Process

Effect of gadolinium incorporation on the structure and luminescence properties of niobium-based materials

“…Figures 3(a) and (b) illustrate the detailed Raman spectra of the samples, which display bands related to the vibrational modes of the matrix. The observed bands are in accordance with the published works [2,4,9,[15][16][17][18][19]. As can be noted, the samples exhibited very complex, similar spectra; as predicted for similar structural observed by the XRD patterns; the exception in some aspects was the sample containing the highest concentration of Gd 3+ .…”

“…Ultraviolet (UV) radiation provides high excitation energy and in the light emitter field, the strategy to obtain white light emitters relies on the use of UV radiation by LEDs coated with blue/green/red luminophores [1,2]. For the red light luminophore, yttrium oxysulfide doped with Eu 3+ (Y 2 O 2 S:Eu 3+ ) is commercially available, however, compared with the blue and green phosphors, the efficiency of Y 2 O 2 S:Eu 3+ is about eight times lower and a mixture containing 10% blue, 10% green, and 80% red is necessary to obtain appreciable color rendering [2,3]. In addition, it has a shorter lifetime under UV radiation, and is unstable because it releases hydrogen sulfide.…”

“…In addition, it has a shorter lifetime under UV radiation, and is unstable because it releases hydrogen sulfide. Therefore, it is mandatory that scientists design new processes and search for novel materials to synthesize stable luminophores that can efficiently absorb near UV radiation while emitting red light [1][2][3].…”

“…Although GdNbO 4 presents features like high chemical stability and a self-activated luminescent center, which suggest its potential use as a host matrix for rare earth ions (RE 3+ ), there is few research on niobium-based oxide luminophores sensitized with gadolinium [8]. Therefore, it is known that particle morphology and size affect the luminescent properties of niobium oxide-based phosphors; that is, the features of the material depend on the methodology used to prepare the solid [2,9,10].…”

“…Among the various methodologies that are available to synthesize luminophores, the non-hydrolytic sol-gel process stands out as one of the most advantageous: it yields highly pure products (the metallic oxides originate in situ) with fewer pores; occurs at relatively low temperatures; allows for incorporation of organic species, to give more homogeneous hybrid materials; and is easier to reproduce [2,11]. Acosta et al [12] developed the non-hydrolytic sol-gel process, which consists of the reaction of a metallic or semi-metallic halide (M-X) with an alkoxide (M′-OR), to produce an inorganic oxide chain (M-O-M′).…”