Photoluminescence Properties of Cr3+-Activated Oxide Phosphors

The Cr3+-activated phosphor properties are discussed in detail from an aspect of spectroscopic point of view. The host materials considered here are a various kind of oxide compounds. The photoluminescence (PL) and PL excitation spectra of the Cr3+-activated oxide phosphors are analyzed based on Franck-Condon analysis within the configurational-coordinate model. A new method is proposed for obtaining reliable crystal-field (Dq) and Racah parameters (B and C) based on a general ligand field theory with paying an attention to difficulty in the exact estimation of such important ligand field parameters. The intra-d-shell Cr3+ states, such as E-2(g) ((2)G), T-4(2g) (F-4), and T-4(1g) (F-4), in various oxide hosts are determined and plotted against Dq in the Tanabe-Sugano energy-level diagram. The results obtained are summarized in graphical and tabular forms. A comparative discussion of Cr3+ ion as an efficient activator in oxide and fluoride hosts is also given. The present analysis method can be used to predict an energy of Cr3+ emission and/or to check a validity of the Racah parameter values for a variety of Cr3+-activated phosphors and related optical and optoelectronic device applications.

Automated summary

The properties of Cr3+-activated phosphors in oxide hosts are discussed in detail from a spectroscopic perspective, with a proposed method for obtaining reliable crystal-field and Racah parameters. Results are summarized graphically and tabularly, with a comparative discussion on the efficiency of Cr3+ ion as an activator in different hosts. The analysis method presented can be used for predicting Cr3+ emission energy and checking the validity of Racah parameter values for various applications.