Transcript 幻灯片 1 - Science24.com

3+
Sm -Doped
Synthesis and Luminescence Properties of
Sr3B2SiO8 Phosphors
for Near-UV pumped light-emitting diodes
Jianfeng Sun
Department of Chemistry, Tsinghua University, Beijing, P. R. China
Email: [email protected]
Motivation
Examples of LED devices (left) and schematic depiction
of a warm-white-emitting diode based on a blue LED
coated with a green and a red phosphor (right)
The rare earth-doped phosphors
excited by near-UV light have attracted
extensive research interest because
they are irreplaceable components of
white LEDs. However, most available
phosphors
usually
offers
the
unsatisfactory
optical
indexes.
Therefore, it is still necessary to seek
some new phosphors in order to
satisfy the applications of white LEDs.
In this poster, we demonstrated the
structure and luminescence properties
of Sm3+-doped Sr3B2SiO8 (SBSO)
phosphors.
Crystallization behavior
Color diagram of the CIE (Commission Internationale
d’Eclairage): by mixing of the three emissions A, B, and
C defined by their color coordinates, all white shades
within the triangle are accessible.
B. ZnS: (Cu+, Al3+)
C. Ca2Si5O8: Eu2+
A. BAM (BaMgAl10O17: Eu2+)
Structure
The TG-DTA (left) and XRD (right) curves indicate the crystallization of SBSO:
Sm3+, Na+ precursors entirely completes at 1050 oC.
The compound SBSO, crystallizing in an orthorhombic system with Pnma space group and
reported lattice constants a = 12.361(4) Å, b = 3.927(1) Å, c = 5.419(1) Å, and the cell volume V
= 263.05(11) Å3, has a pseudo chained structure consisting of a series of TOx polyhedra (T = B,
Si; x = 3-4).
Photoluminescence properties of SBSO: xSm3+, xNa+ (x = 0.01-0.09) phosphors
Under near-UV excitation (400 nm), the SBSO: xSm3+, xNa+ phosphors exhibits three novel emission bands peaking at 561, 600, and 648 nm,
respectively, corresponding to the characteristic emission transitions of 4G5/2-6HJ (J = 5/2, 7/2, and 9/2) of Sm3+ ions in SBSO host lattice.
The diffuse reflection spectra of
BSBO and BSBO: 0.03Sm3+, 0.03Na+
The PLE spectra of BSBO:
(λem = 613 nm)
xSm3+,
xNa+
The PLE spectra of BSBO: xSm3+, xNa+
(λex = 400 nm)
The theoretical calculation based on the Judd-Ofelt (J-O) theory and CIE coordiantes of BSBO: xSm3+, xNa+ phosphors
xSm3+,
The PL decay curves of BSBO:
xNa+ (λex = 400 nm, λem = 600 nm)
PL data of the selected phosphors of BSBO: xSm3+,
xNa+ calculated on the basis of the J-O theory
CIE chromaticity diagram of BSBO: 0.03Sm3+,
0.03Na+ under 400 nm excitation
Summary
References
We have synthesized and investigated the luminescence
characteristics of Sm3+-doped SBSO phosphors. In addition, the
effects of charge compensation on the luminescence behaviors of
BSBO: xSm3+, xM+ where M+ represented a monovalent cation like
Li+, Na+, or K+ acting as a charge compensator, have also been
investigated in the paper. In view of their strong absorption in the
near-UV region, and the intense visible emitting light, the Sm3+doped BSBO phosphors can serve as potential new materials for
near-UV-pumped white LEDs.
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Acknowledgment
This work was financially supported by the State Key Program of National Natural Science of China (Grant No. 51132005)