Review—Temperature Dependence of Transition-Metal and Rare-Earth Ion Luminescence (Mn4+, Cr3+, Mn2+, Eu2+, Eu3+, Tb3+, etc.) II: Experimental Data Analyses

Abstract

An analysis method presented in a separate article of I can be applicable not only to Mn4+ ion, but also to other kinds of ions like Mn4+, Cr3+, Mn2+, Eu2+, Eu3+, and Tb3+. Herein, the characteristic luminescence behaviors of such ion-activated phosphors are summarized from various spectroscopic points of view. The phosphors discussed in this article are classified into five groups: (i) transition-metal 3d 3-activated phosphors of types F-Mn, O-Mn (Mn4+), and O-Cr-A (Cr3+), (ii) transition-metal 3d 3-activated phosphors of types F-Cr and O-Cr-B (Cr3+), (iii) transition-metal 3d 5-activated phosphors (Mn2+), (iv) divalent rare-earth ion-activated phosphors (Eu2+), and (v) trivalent rare-earth ion-activated phosphors (Eu3+, Tb3+). Particularly, the effects of the crystal field on the electronic energy-level scheme of these ions are demonstrated in graphical form with presenting their typical excitation absorption and luminescence spectra. The phosphor materials actually examined here are: (i) Rb2GeF6:Mn4+ and K2SiF6:Mn4+, (ii) RbIn(WO4)2:Cr3+, (iii) Zn4B6O13:Mn2+, (iv) SrSi2O2N2:Eu2+, and (v) CaTiO3:Eu3+ and Ca3Ga2Ge3O12:Tb3+. The experimental photoluminescence intensity (I PL) vs T data for these phosphors are analyzed using our proposed model. An electron trap model has recently been proposed as an alternative model of ours to explain negative or zero thermal quenching phenomenon. Detailed discussion is also given on the reliability of this electron-trap model.