Wet chemically prepared terbium activated sodium calcium chlorosulfate phosphor for solid state lighting industry.

Rare earth ion plays an important role in the solid state lighting industry. Here, the terbium (III) ion doped sodium calcium chlorosulfate phosphor was prepared via wet chemical method. Structure, bonding between each element of the sample and morphology of the sample were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM), which showed that the samples were crystallized in a well known structure. XRD study shows the crystalline nature of the phosphor materials prepared at low temperature. Photoluminescence study of prepared phosphor was done using SHIMADZU Spectrofluorophotometer RF-5301 PC with a xenon lamp as the excitation source. The excitation spectra are obtained between 280 and 430 nm ranges on doping of terbium (III) ion. Among all these transitions excitation at 380 nm is strong excitation owing to ⁷F₆ → ⁵G₆ transition. The emissions from terbium (III) ions are at 416, 437, 490 and 545, 586, 621 nm. These emissions are attributed to ⁵D₃→⁷F₅ (417 nm), ⁵D₃→⁷F₄ (437 nm), ⁵D₄→⁷F₆ (491 nm) and ⁵D₄→⁷F₅ (545 nm), ⁵D₄→⁷F₄ (588 nm), ⁵D₄ → 7F₃ (624 nm) transitions of terbium (III) ions. Among these strong emission peak appears in green region at 545 nm. [ABSTRACT FROM AUTHOR]