Synthesis, photoluminescence and theoretical explanations of trivalent europium-doped lithium nitrate crystal

Abstract

Novel red emitting europium-doped lithium nitrate were prepared by using the solid-state reaction, and characterized by the X-ray diffraction and photoluminescence techniques. The characteristic main emission bands from 5D0 to 7F1 (594nm, yellow) and to 7F2 (615, 625nm, red) transitions of trivalent europium were observed in the emission spectra of europium-doped lithium nitrate while excited by the near-ultraviolet light (394nm). The effects of the europium concentration in europium-doped lithium nitrate phosphors on the photoluminescence were investigated in detail. The results showed that the relative photoluminescence intensity increases with europium-concentration increasing until a maximum intensity is reached, and then it decreases due to concentration quenching, which are explained satisfactorily with the luminescent theory. The optimum concentration (∼0.07M) of europium in lithium nitrate is obtained. The f-f transitions of europium in lithium nitrate are calculated by diagonalization crystal-field energy matrix of 4f6 ion, and the optical spectra of europium-doped lithium nitrate are explained satisfactorily. The results are discussed.