지원사업
학술연구/단체지원/교육 등 연구자 활동을 지속하도록 DBpia가 지원하고 있어요.
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연구자들이 자신의 연구와 전문성을 널리 알리고, 새로운 협력의 기회를 만들 수 있는 네트워킹 공간이에요.
초록· 키워드
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Two types of Tb- and Na-substituted green phosphors $Ca_{(1-1.5x)}WO_4:Tb_x^{3+}$: and $Ca_{(1-2x)}WO_4:Tb_x^{3+},Na_x^+$ were synthesized with various x values, using a solid-state reaction. The former phosphors contained both substitutional and vacancy point defects, while the later had only substitutional defects. X-ray diffraction results showed that the main diffraction peak, (112), was centered at $2{\theta}=28.72^{\circ}$ and indicated that there was no basic structural deformation caused by substitutions or vacancies. The photoluminescence emission and photoluminescence excitation spectra revealed the optical properties of trivalent terbium ions, $Tb^{3+}$. Typical transitions, $^5D_3{\rightarrow}^7F_6,\;^7F_5,\;^7F_4$ and $^5D_4{\rightarrow}^7F_6,\;^7F_5,\;^7F_4,\;^7F_3$, and cross relaxations were observed. Subtle differences in the photoluminescence of green phosphors were observed as a result of the point defects. The FT-IR spectra indicated that some of the ungerade vibrational modes had shifted positions and changed shapes, spreading out over a wide range of frequencies. This change can be attributed to the different masses of $Tb^{3+}$ and $Na^+$ ions and $V_{Ca}$" vacancies compared to $Ca^{2+}$ ions. The gerade normal modes of the Raman spectra exhibited subtle differences resulting from point defects in $Ca_{(1-1.5x)}Tb_xWO_4$ and $Ca_{(1-2x)}Tb_xNa_xWO_4$.
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