Luminescence of Iron‐Activated Lithium Meta Gallate

Abstract

LiGaO2: Fe is an efficient phosphor under both ultraviolet and cathode-ray excitations, with peak emission at 742 nm in the near-infrared region. It is best prepared at about 1000~ with stoichiometric proportions of the host ingredients and 0.01 moles Fe2Os. At this optimum Fe 3+ concentration, the relative quantum efficiency is about 80%. Potential use in fluorescent lamps is discussed in relation to plant growth applications ~or activation of the enzyme phytochrome.The behavior of Fe 3 + ions in various hosts has been studied extensively. In LiA15Os with a spinel-like structure (1), Fe 8+ activator has a peak emission at about 680 nm under 254 nm excitation (2). On the other hand, Fe3+-activated LiA102 with a distorted tetragonal structure (3) emits at about 740 nm (4). In the search for efficient near-infrared emitting phosphors for special fluorescent lamp applications, the author examined several gallium-containing hosts for possible emission when activated with iron. LiGaO2: Fe was found to be an efficient phosphor under both ultraviolet (u.v.) and cathode-ray (CR) excitation. This paper describes the preparation, luminescent properties, and performance of LiGaO2:Fe in fluorescent lamps. Comparisons with LiA102:Fe phosphors are also described. Some potential uses in fluorescent lamp applications are indicated.

Luminescence of Rare Earth Activated Lutetium Oxyhalide Phosphors

“…The complete spectra between 300 and 700 nm showed no other unusual emission characteristics and are similar to emission spectra reported for the corresponding LaOC1 phosphors. Assignments of transitions are not indicated in most cases since these correspond closely to those reported previously for LaOBr phosphors (1)(2)(3)(4)(5)(6). The emission spectra, under CR excitation, for LuOBr: 0.002 Tb are shown in Fig.…”

“…The 403 nm emissions are more intense under 254 nm excitation. By contrast, LaOBr:0.005Ce has a single emission peaking at 430 nm with a half-intensity width of 70 nm (5). Figure 7 shows the emission spectra for LuOBr:0.005Sm using CR excitation.…”

Single-LED solar simulator for amorphous Si and dye-sensitized solar cells

“…To produce the sunlight spectra, we selected 10 UV-active phosphors with broadband luminescence. We used vanadate phosphors (CsVO 3 and Zn 3 V 2 O 8 ) for visible light emission, Eu 2+ / Mn 2+ -doped silicates [38][39][40] and aluminosilicates 41 for UV and visible light emission, and Fe 2+ -doped gallate 42 for near-infrared emission. Polycrystalline phosphor powders were synthesized by solid-state reactions using previously reported procedures (Table S1 †).…”

“…Polycrystalline phosphor powders were synthesized by solid-state reactions using previously reported procedures (Table S1 †). [38][39][40][41][42] The purity and crystallinity of the polycrystalline samples were conrmed by X-ray powder diffraction. All polycrystalline samples consisted of a well-crystallized single phase with no impurities (Fig.…”

High-Pressure Near-Infrared Luminescence Studies of Fe3+-Activated LiGaO2

“…It shows a strong persistent luminescence under ambient conditions along with thermoluminescent and pyroelectric luminescent properties. Consequently, it is highly regarded as a promising phosphor material for fluorescent lamps in plant growth applications. − Apart from its optical properties, solid β-LiGaO 2 also demonstrates intriguing mechanical characteristics such as elasticity and piezoelectricity . β-LiGaO 2 has also found applications as a ceramic tritium breeder material in experimental fusion reactors. , It serves as a lattice-matched substrate for the growth of GaN, InN, and ZnO and as a solid gallium precursor source material for bulk GaN crystal growth. , Recent studies have indicated the applicability of these ceramic phosphors in various biological fields due to their biocompatible nature and promising NIR luminescence properties when doped with transition-metal elements. , Iron (Fe 3+ ) is an efficient transition-metal dopant for achieving the NIR luminescence and persistent luminescence in LiGaO 2 . − …”