Investigation on the luminescent properties of a novel Bi3+ based blue long afterglow phosphor Ca14Ga10Zn6O35:Bi3+

Abstract

A series of Bi3+ based blue long afterglow phosphor Ca14Ga10Zn6O35:Bi3+ were successfully synthesized via solid state reaction method. Under ultraviolet excitation of the samples, a blue emission originated from 3P1→1S0 transition of Bi3+engendered a broadband from 380 to 600 nm with peak at around 432 nm. The peak positions of the emission curves have experienced a slight red shift from 432 to 442 nm when the concentrations of Bi3+ were increased from 0.1 % to 1.5 %. After excitation stopped, the persistent luminescence from Bi3+ ions could last more than half an hour. The afterglow duration times were shortened remarkably with the increasing concentration of Bi3+, from several thousand seconds to several hundred seconds, along with decreased afterglow intensity. With the alkaline metals Li+ and Na+ co-doped to provide charge compensation, the emission intensity of Bi3+ ions was increased, together with compensated by the shortened persistent time. A series of thermoluminescence glow curves of 0.1 % Bi3+ doped sample were measured with different delay times to detect the population dynamics of traps. With the systematical experimental results, a reasonable model was proposed to illuminate the mechanism of the emission and persistent phenomenon of this promising novel Bi3+ based blue long afterglow phosphor.