Details

Autor(en) / Beteiligte

• Maphiri, V.M.
• Mhlongo, M.R.
• Hlatshwayo, T.T.
• Motaung, T.E.
• Koao, L.F.
• Motloung, S.V.

Titel

Citrate sol-gel synthesis of BaAl2O4:x% Cu2+ (0 ≤ x ≤ 1) nano-phosphors: Structural, morphological and photoluminescence properties

Ist Teil von

• Optical materials, 2020-11, Vol.109, p.110244, Article 110244

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2020

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• This paper reports on the effects of varying the Cu2+ doping concentration on the structure, morphology and optical properties of the BaAl2O4 phosphor. BaAl2O4:x% Cu2+ (0 ≤ x ≤ 1) series were successfully synthesized via citrate sol-gel method. The X-ray diffraction (XRD) results revealed that the prepared phosphor sample consist of a single phase hexagonal structure. The presence of Ba, Al, O and Cu were confirmed by the energy dispersive X-ray spectroscopy (EDS). Scanning electron microscope (SEM) revealed that the morphology of the prepared samples highly depends on the Cu2+ concentration. Transmission electron microscopy (TEM) results revealed the hollow tubular and nano-nature of the crystallite sizes. When the un-doped sample was excited at 283 nm, the photoluminescence (PL) results revealed six emission peaks located at 420, 435, 457, 521, 612 and 722 nm, which were attributed to the intrinsic intra band gap defects within the BaAl2O4 (host). The emission at 425 nm observed for the BaAl2O4:Cu2+ samples was attributed to the 3d84s1 → 3d9 transition in Cu2+ ion. The optimum doping Cu2+ concentration was found to be 0.075% Cu2+. Critical energy transfer distance (Rc) of Cu2+ ions was found to be 12.01 Å, which suggested that the multipole-multipole interaction was the main reason for the luminescence quenching. The International Commission on Illumination (CIE) colour showed that the bluish emission colour of the prepared samples depends on the excitation wavelength and Cu2+ concentration. Thermo stimulated luminescence (TSL) of the host material showed the presence of both the swallow and deep traps respectively located at 75 and 240 °C. •Hexagonal nanocrystalline BaAl2O4:x% Cu2+ (0 ≤ x ≤ 1) phosphor powders were succesfully prepared via the citrate sol-gel technique.•Photoluminescence emission intensity of the powder sample was dependent on the Cu2+ concentration.•Both emissions from the host and Cu2+ were observed.•The Commission on Illumination color coordinate evidently showed that the bluish emission depends on the Cu2+ concentration.•Themoluminescence results showed the precence of both the shallow and deep level tranps in BaAl2O4: Cu2+ phosphor material.