Structure, photoluminescence, and thermal quenching properties of Eu doped Sr₂Al_xSi_5−xN_8−x/3red phosphors

Abstract

Eu 2+ doped Sr 2 Al x Si 5−x N 8−x/3 red phosphors have been synthesized by a solid state reaction method, with the aim of improving their thermal quenching properties. The XRD patterns confirm that Al 3+ can efficiently substitute Si 4+ in the Eu 2+ doped Sr 2 Si 5 N 8 host. The crystal structure is studied by Rietveld refinement, selected-area electron diffraction (SAED) and solid-state NMR analysis. With an increase in x, the emission spectra show no obvious shift and the full width at half maximum (FWHM) increases from 86 to 94.2 nm.Remarkably, the thermal quenching properties are obviously improved as appropriate Al 3+ substituted Si 4+ .The corresponding mechanism is discussed in detail based on the influence of size mismatch and the configurational coordinate model.

Structure and luminescence properties of La6Ba4(SiO4)6F2:Dy3+ phosphor with apatite structure

“…Because of nonradiative relaxation through the excited state and its crossover to the ground state, the thermal quenching effect, where the probability of non-radiative transition strictly relies on the temperature causes PL quenching of Dy 3+ emission at high temperatures. The relationship between the temperature and photoluminescence intensity could be described with a modi-ed Arrhenius equation: [56][57][58] IðTÞ…”

Optical and structural properties of the Fe3+-doped Lu3Al5O12:Ce3+ garnet phosphor

“…Activation energy (Δ E ) was calculated using the Arrhenius equation: 45 where I and I 0 indicate the emission intensity at temperature T and the initial temperature (in absolute scale), respectively. A is a constant, and k B is the Boltzmann constant (8.629 × 10 −5 eV −1 ).…”

Synthesis, electronic structures, and photoluminescence properties of an efficient and thermally stable red-emitting phosphor Ca3ZrSi2O9:Eu3+,Bi3+ for deep UV-LEDs

“…The photoluminescence (PL) intensity increase is generally ascribed to the formation of defect levels in the phosphor, which can capture electrons and then release them with increasing temperature, causing the increase of the PL intensity. 40,41 Because of the effect of defects in increasing the thermal stability, this Bi 3+ -doped phosphor can remain at 84.2% of the initial quantum yield (at room temperature) when the temperature was increased up to 150 C. The yield is better than that of Y 2 O 3 :Eu 3+ (approximately 81%) and comparable to commercial Sr 2 Si 5 N 8 :Eu 2+ (approximately 85%), [42][43][44] and is much higher than that without Bi 3+ doping (70.1%). This thermal stability enhancement is different from the traditional reduction of cross relaxation or thermal ionization, 45,46 mainly ascribing to the appropriate amount of defects created by Bi 3+ doping.…”