Structural and Luminescence Properties of Ca\(^{2+}\)-Substituted Self-Activated Photoluminescence Material of Na\(_{2}\)TiSiO\(_{5}\) Dzaky Dian Ruhimat (a), Fainan Failamani (a), Bambang Prijamboedi (a), *
(a) Inorganic and Physical Chemistry Research Division, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology
Jl. Ganesha 10, Bandung, 40132, INDONESIA
*E-mail : prijamboedi[at]itb.ac.id
Abstract
White light emitting diode (WLED) is widely used as lighting devices. Self-activated luminescence materials, such as Na\(_{2}\)TiSiO\(_{5}\) (NTSO) becomes a good candidate for the WLED emitting device, because it does not contain any rare-earth elements as luminescence center. However, the low emission intensity of NTSO limits its application as commercial LED. In order to improve its luminescence intensity, one needs to study the photoluminescence mechanism. It was proposed that the different coordination of Ti\(^{4+}\) is responsible for the luminescence properties. Therefore, we study the effects of Ca\(^{2+}\) substitution into Na\(^{+}\) site in NTSO. The Ca\(^{2+}\) ions are expected to change the coordination of Ti\(^{4+}\). The Na\(_{2(1-x)}\)Ca\(_{x}\)TiSiO\(_{5}\) (x = 0.00, 0.50, 1.00) samples were synthesized by means of solid state method, and its structural properties were characterized and analyzed by X-ray diffraction (XRD) method and Rietveld refinement, respectively. The local Ti\(^{4+}\)-O\(^{2-}\) coordination is studied by IR spectroscopy. The absorption and emission properties were studied by UV diffuse reflectance spectroscopy (UV-DRS) and photoluminescence (PL) spectroscopy, respectively. The effects of Ca\(^{2+}\)-substitution into NTSO to the crystal structure, optical absorption and emission would reveal the photoluminescence mechanism in this compound.
