Enhanced luminescence efficiency and thermal stability via introduction of non-rare earth Bi3+ in Gd5Si2BO13:Eu3+

Abstract

A series of Gd5Si2BO13:Eu3+ and non-rare earth Bi3+ ions doped Gd5Si2BO13:Eu3+ phosphors was successfully synthesized via high-temperature solid-state method, and the as-obtained phosphors were studied on their phase structures, luminescence characteristics, thermal stability and luminescence lifetime. Transient fluorescence spectroscopy data show that the addition of Bi3+ can obviously enhance the emission intensity of Eu3+ in the near-ultraviolet band owing to energy transfer from Bi3+ to Eu3+. Besides, the addition of Bi3+ can improve the thermal stability of a single-doped phosphor Gd5Si2BO13:0.35Eu3+ from 70.33% to 87.45% at 150 °C and the quantum yield from 58.80% to 78.61% at room temperature. Finally, Gd5Si2BO13:Eu3+,Bi3+ was used to encapsulate white light-emitting diodes (WLEDs) with green ((Ba,Sr)2SiO4:Eu2+) and blue (BaMgAl10O17:Eu2+) commercial phosphors. The color rendering index of WLEDs was calculated to be larger than 90, and the color temperature was estimated to be 4300–4500 K, which demonstrate that Gd5Si2BO13:Eu3+,Bi3+ can be regarded as a red phosphor with great potential application. This paper can provide a new insight into design of high-efficiency phosphors by introducing non-rare earth Bi3+ ions via energy transfer from Bi3+ to Eu3+.