Wydział Chemii

Małgorzata Puchalska

Marcin Sobczyk

J. Targowska

Adam Watras

Eugeniusz Zych

2013

Journal of Luminescence

143

503-509

10.1016/j.jlumin.2013.05.020

Naukowa

Angielski

Artykuł

Two series of calcium aluminates: Singly doped CaAl₄O₇:Yb(x%) and co-doped CaAl₄O₇:Yb(x%),Na(x%) (x=0.002, 0.01, 0.02, 0.04, 0.05, 0.06, 0.07, 0.1) were synthesized by a modified Pechini citrate process and their optical properties at 298 K and 77 K were investigated. Direct excitation of Yb³⁺ by means of ²F_7/2→²F_5/2 absorption at 940–980 nm leads to a reversed ²F_5/2→²F_7/2 transition giving Yb³⁺ emission in the range of 970–1130 nm as well as bluish-green up-converted (UC) luminescence whose energy doubles that of the near-IR (NIR) one. The UC luminescence was characterized by absorption and emission spectra, decay time measurements as well as its intensity dependence on the pumping power. The effect of dopant concentration and charge compensation by co-doping with Na⁺ ions on morphology and luminescent properties were also studied. The co-doping affected the luminescence behavior but had no influence on the powders morphology. Na⁺ addition led to narrowing of NIR luminescence bands, suggesting smaller disturbance of Yb³⁺ ions local symmetries and also significantly enhanced NIR and UC luminescence of Yb³⁺.

Calcium aluminate, cooperative liminescence, Yb3+ luminescence, charge compensation

http://dx.doi.org/10.1016/j.jlumin.2013.05.020

http://www.elsevier.com