Behavior analyses of chromium into LiZnNbO4 host through optical spectroscopy and X-ray diffraction

Abstract

A LiZnNbO4 sample was produced through the solid-state reaction method, according to which, chromium was introduced in the sample as impurity. X-ray diffraction (XRD), luminescence, excitation, emission decay time and emission quantum efficiency analyses were carried out. Structural analysis based on the sample's XRD data showed LiZnNbO4 compound belonging to the P4122 space group. Luminescence measurements evidenced broad emission band centered at 800 nm, which was associated with spin-allowed electronic transition from the excited state 4T2(4F) to the fundamental state 4A2(4F). Emission decay time reached 7.8 μs under 460 nm excitation and 0.43 quantum efficiency. Excitation spectrum showed bands associated with of Cr3+ ions transitions4A2(4F)→ 4T1(4F) and 4A2(4F)→ 4T2(4F), at 460 nm and 644 nm, respectively in octahedral symmetry. Crystal field parameter Dq = 1553 cm−1 and Racah B = 621 cm−1 were found by using transition energies from both the excitation spectrum and Tanabe-Sugano matrices.