Cd3Al2Ge3O12:Mn2+锗酸盐石榴石光谱性质

本文报道室温下Cd₃Al₂Ge₃O₁₂:Mn²⁺(简称CAGG:Mn²⁺)锗酸盐石榴石的漫反射光谱、激发和发射光谱.在UV光激发下,在CAGG中Mn²⁺离子发射强黄光,这是基质到Mn²⁺离子无辐射能量传递的结果.Mn²⁺的黄发射带是由一个弱的红带和一个强的绿带所组成.讨论了这两个Mn²⁺发射带的起因.

SPECTROSCOPIC PROPERTIES OF Cd3Al2Ge3O12:Mn2+ GERMANATE GARNET

The diffusive reflection spectra, the excitation and emission spectra of Cd3Al2Ge3O12 host (abbr.: CAGG)and Cd3Al2Ge3O12: Mn2+ (abbr.: CAGG: Mn2+ )garnet phosphors at RT have been systematically investigated. The diffusive reflection spectrum (Fig.1) of the CAGG: Mn2+ shows a strong absorption band at about 250urn which coincides with that of the CAGG host and three weak absorption bands at 360urn, 397urn and 414um from 4T2, 4A1 and 4E levels of Mnz+, respectively. As shown in Fig. 2 the excitation spectrum of Cd3Al2Ge3O12: Mn2+ is the same as that of the CAGG host.CAGG host Under excitation of 254um at RT shows a blue emission band extending from 350um to 560nm with a peak at about 450um. Photoluminescence spectrum ofCd3Al2Ge3O12: Mn2+ garnet consists of two emission bands (to see Fig. 3). The emission band in blue region is from CAGG host and the strong emission band in yellow region is from Mn2+ emission, whose peak is at 570nm resulting from transition of 4T1 (G) to 5A1 level of the Mn2+ ion. With increasing the concentration of the Mn2+ ion, the emission intensity in the blue region from CAGG host decreases and then emission intensity of Mn2+ ion increases. The emission of CAGG host is completely quenched when the concentration of Mn2+ion reaches 0. 2%.We consider that the nonradiative resonance energy transfer from CAGG host to Mn2+ ion occurs in the system of Cd3Al2Ge3O12: Mn2+ garnet phosphors. The spectroscopic properties of the yellow band of the Mn2+ ion in CAGG garnets have been disc ussed.