Wydział Chemii

Piotr Solarz

Mirosław Karbowiak

Michał Głowacki

Marek Berkowski

Ryszard Diduszko

Witold Ryba-Romanowski

2016

Journal of Alloys and Compounds

661

419-427

10.1016/j.jallcom.2015.11.155

Naukowa

Angielski

Artykuł

Undoped and samarium-doped SrB₄O₇polycrystalline samples were prepared by a solid state reaction method in air. XRD examination revealed that the undoped sample is consistent with the pure SrB₄O₇phase but in samarium-doped sample in addition to the main tetraborate SrB₄O₇phase there is a little amount of metaborate. Based on preliminary spectroscopic examination it was ascertained that Sm²⁺ions are incorporated without measurable traces of Sm³⁺admixture. High resolution luminescence spectra and decay curves of Sm²⁺luminescence were measured as a function of temperature in the 5-550K temperature region. Energies of crystal field components of the⁷F_J(J=1-5) multiplets at 5K and those of the⁵D₁multiplet at 300K were determined from luminescence spectra and used subsequently as input data for the crystal field calculation. Performed crystal field calculation predicts the energy level scheme for the 4f⁶configuration of Sm²⁺in SrB₄O₇up to 29000cm⁻¹and makes it possible to assess the contribution of transitions from the excited states above the⁵D₁to luminescence phenomena. Evaluated activation energy E_a∼4600cm⁻¹characterizing a steep decrease of the⁵D₀lifetime of Sm²⁺between 320K and 550K indicates strongly that electronic origin of the lowest energy⁷F₀- 4f⁵d¹vibronic transitions is located around 19200cm⁻¹, slightly below the⁷F₀-⁵D₃transition energy.

Divalent samarium, luminescence, Tetraborate, Crystal field, Red phosphor

http://dx.doi.org/10.1016/j.jallcom.2015.11.155

http://www.elsevier.com