Review—Photoluminescence Spectroscopy of Mn<sup>2+</sup>-Activated Phosphors: Part I. Fundamentals
Sadao Adachi
Abstract
The purpose of this review article is to present and clarify the various phosphor properties of Mn 2+ activator ion in the intra-3 d 5 -shell electronic configuration. Even though the concepts of intra-3 d 5 -shell electronic configuration in Mn 2+ ion are well understood at this time, some important properties of this ion in the various host materials have been hampered by a lack of definite knowledge of such phosphor systems. The Mn 2+ -activated phosphor properties examined in the present article can be classified into seven groups: (1) spectral feature of Mn 2+ -ion photoluminescence (PL) and PL excitation (PLE) transitions, (2) temperature dependence of PL intensity, (3) temperature dependence of PL decay lifetime, (4) Mn 2+ concentration effects on PL properties, (5) excitonic transition-related Mn 2+ luminescence, (6) crystalline morphology effects: bulk sample vs microcrystalline sample, and (7) crystalline morphology effects: quantum confinement-induced phenomena. Key expressions for theoretically analyzing PL and PLE spectral features, together with PL intensity variation with temperature, for the Mn 2+ emission were discussed in detail. A detailed discussion is also given of the acceptability of such phosphor properties and behaviors from an applicational point of view.