Enhanced luminescence intensity of novel red-emitting phosphor -Sr3Lu2(BO3)4:Bi3+,Eu3+ via energy transfer

Irish Valerie B Maggay,Pin-Chun Lin,Wei-Ren Liu

doi:10.1186/s40539-014-0013-6

Irish Valerie B Maggay, Pin-Chun Lin + Show 1 more

Open Access

https://doi.org/10.1186/s40539-014-0013-6

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Abstract

Abstract Bi3+/Eu3+ co-activated Sr3Lu2(BO3)4 was successfully synthesized via a solid state reaction. The optimal concentration of Bi3+,Eu3+ and Bi3+/Eu3+ are 1 mol%, 60 mol% and 1 mol%/20 mol%, respectively. The emission spectra of Sr3Lu2(BO3)4:Bi3+, Eu3+ gives three peaks located at 405 nm, 489 nm which were attributed to Bi3+ S6 (blue) and C2 (green) site symmetry, respectively and 610 nm which was ascribed to Eu3+ (5D0 → 7 F2) transition. The emission intensity of Bi3+ decreases with increasing Eu3+ content which indicates that a efficient energy transfer occurred in the Sr3Lu2(BO3)4 host. The relative intensity of Sr3Lu1.79(BO3)4:0.01Bi3+,0.20Eu3+ excited at 327 nm and 370 nm was remarkably enhanced by 201% and 265%, respectively, via the energy transfer from Bi3+ to Eu3+. The results indicate that Sr3Lu2(BO3)4:Bi3+, Eu3+ is a potential novel red-emitting phosphor for UV LED applications.

Highlights

There has been a rapid increase in the number of researches on white-light emitting diodes (W-LEDs) and it has begun replacing conventional lighting sources due to its advantages such as high brightness, high energy efficiency, low power consumption, longer working performance and low environmental risk [1,2,3,4,5,6]
The results show that the as-synthesized Sr3Lu2(BO3)4 and Bi3+, Eu3+ or Bi3+/Eu3+ co-doped Sr3Lu2(BO3)4 are in well consistent with standard pattern of ICSD 10213, indicating that single-phased phosphors were successfully obtained by a solid state reaction
The host phosphor belongs to Sr3RE2(BO3)4 (RE: Gd3+, Y3+, La3+ and Lu3+) system which has an orthorhombic structure with Pc21n space group

Summary

Introduction

There has been a rapid increase in the number of researches on white-light emitting diodes (W-LEDs) and it has begun replacing conventional lighting sources due to its advantages such as high brightness, high energy efficiency, low power consumption, longer working performance and low environmental risk [1,2,3,4,5,6]. The common fabrication of W-LEDs involves a blue-emitting InGaN chip and a yellow emitting phosphor Y3Al5O12:Ce3+ (YAG) [1,2,7]. This combination displays low color rendering index (Ra) of ~80 and high color temperature which is due to the insufficiency of red emission in the visible spectrum [5]. Eu3+ rare earth ions have drawn much attention of scientists in obtaining a redemitting due to its lowest excited level 5D0 of the 4f6 configuration which is located below the 4f65d configuration and it principally displays very sharp red emission lines at 5D0-7 F2 transition around 610 ~ 618 nm [8,9]. Liu et al [1] found that the luminescence intensity and quantum efficiency of ZnB2O4:Bi3+, Eu3+

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