Optical Characteristics of Porous Alumina Modified by Chromium Oxide

Abstract

In this paper, the chromium ions luminescence in Cr2O3/Al2O3 nanocomposites has been studied. No photoluminescence from the nanocomposite was observed at room temperature, while at liquid nitrogen temperature the two broad bands were detected at 497 and 665[Formula: see text]nm caused by [Formula: see text]- and [Formula: see text]-type oxygen vacancies and Cr[Formula: see text] and Mn[Formula: see text]impurity centers. The photoluminescence band observed at 616[Formula: see text]nm is attributed to Cr[Formula: see text] ions. The excitation of Cr[Formula: see text] ions occurs at 265 and 375[Formula: see text]nm, and their formation is the result of Cr[Formula: see text]–Cr[Formula: see text] redox processes on the surface of Cr2O3 crystallites at the annealing temperatures of 400–[Formula: see text]C.