Enhanced long-persistence of Ca2Al2SiO7:Ce3+ phosphors for mechanoluminescence and thermoluminescence dosimetry

Abstract

Ca 2 Al 2 SiO 7 phosphors having various concentration of Ce 3? were synthesized by combustion-assisted method at initiating temperature of 600°C, using urea as a fuel and its XRD, SEM, TEM and EDX were studied. X-ray diffraction (XRD) pattern indicates that the crystal structure of Ca 2 Al 2 SiO 7 is mainly tetragonal and particle size of prepared phosphor was determined by TEM. Scanning electron microscope (SEM) image was recorded to observe the surface morphology. Mechanoluminescence (ML) and thermoluminescence (TL) properties of Ca 2 Al 2 SiO 7 :Ce 3? phosphors was also investigated. The TL intensity of Ca 2 Al 2 SiO 7 :Ce 3? was recorded for different exposure time of c-irradiation and it was observed that TL intensity is maximum for c dose of 1180 Gy. The increase in TL intensity indicates that the concentration of traps increases with c exposure time. The peak of ML intensity versus time curve increases linearly with increasing impact velocity of the moving piston. The ML intensity increases by increasing c irradiation time up to 1180 Gy. The ML and TL spectra of Ca 2 Al 2 SiO 7 :Ce 3? phosphor exhibits a sharp emission at 400 nm wavelength due to transition of Ce 3? ions. Mechanism of TL and ML excitation and suitability of Ca 2 Al 2 SiO 7 :Ce 3? phosphor for radiation dosimetry have been discussed.

Luminescence and structural characterization on praseodymium (Pr3+) doped potassium bromide (KBr) single crystals

“…The morphological study seems to have a flower like structure with large extent of agglomeration. The formation of agglomeration is due to high temperature treatment during growth process, which was reported in earlier work . SEM image shows that the particle size ranges in between a few micrometers to 5 μm.…”

“…We use Chen's peak shape method to analyze activation energy ( E ) and frequency factor ( s ) for the prominent glow peak. These parameters are calculated by the formula reported in earlier work . The Pr 3+ doped KBr crystals consist of two glow peaks with the low temperature peak located at 415 K and the high temperature peak located at 486 K. The high temperature glow peak has high intensity compared with the low temperature glow peak.…”

“…The lattice parameters of the grown crystal is a = b = c = 6.596 Å and α = β = γ = 90°. The average crystallite size from the X‐ray diffraction pattern was calculated using Debye Scherrer relation D = kλ / β cos θ , where k is the dimensionless shape factor with a value close to unity, λ the wavelength of the incident X‐ray radiation CuKα (0.154 nm), β is the full width at half maximum (FWHM) in radian and θ is the corresponding angle of high intensity Bragg diffraction . The calculated average crystallite size is about 2.5 μm.…”

CÔNG NGHỆ CHẾ TẠO VÀ TÍNH CHẤT QUANG CỦA VẬT LIỆU Sr2Al2SiO7 PHA TẠP EUROPIUM

“…Nhiều năm gần đây, vật liệu phát quang trên nền aluminate kiềm thổ pha tạp các nguyên tố đất hiếm như SrAl2O4: Eu 2+ , Dy 3+ ; CaAl2O4: Eu 2+ , Nd 3+ và BaAl2O4: Eu 2+ , Dy 3+ đã được chế tạo và nghiên cứu rộng rãi [1][2][3][4]. Gần đây, vật liệu lân quang dài trên nền silicate alumino kiềm thổ (Sr, Ca)2Al2SiO7 đã được các nhà khoa học quan tâm nghiên cứu [5][6][7][8][9][10][11][12]. Silicate alumino kiềm thổ có tính ổn định hóa học cao và khả năng chịu nước tốt hơn nhiều so với vật liệu phát quang trên nền sunfua và aluminate nên thích hợp làm mạng nền của vật liệu phát quang.…”

Energy Transfer between Ce³⁺-Dy³⁺ in Ca₂Al₂SiO₇: Ce³⁺, Dy³⁺ Phosphor

“…Materials that emit visible light with high luminescent efficiency under stimulation by near UV radiation or blue light have been applied in white LED manufacturing. Alkaline earth alumino silicate materials have attracted a lots of attention from scientist, and become an interesting research topic in the luminescent material field because their high chemical stability and better water resistance compared to the materials on sulfite and aluminate lattice [2][3][4]. This paper presents research results on luminescence and energy transfer from Ce 3+ ion to Dy 3+ ion in Ca2Al2SiO7 lattice.…”