Abstract
Red-emitting Gd2O2S:Eu3+ nanophosphors were successfully prepared using a microwave irradiation method followed by hydrogenation treatment. The optimum calcination temperature (900 ºC) was determined by thermogravimetric-differential scanning calorimetry. The X-ray diffraction results showed that all the samples consisted of the pure hexagonal Gd2O2S:Eu3+ phase. The field emission scanning electron microscopy images showed that the Gd2O2S:Eu3+ nanophosphors were spherical, and their average particle diameter increased parallel with the microwave irradiation power. The photoluminescence spectra (under 325-nm excitation) of the samples exhibited red emission corresponding to the 5D0→7F2 transition of Eu3+ ions. A Gd2O2S:Eu3+ nanophosphor screen film was fabricated using the particle-binder sedimentation method. The result shows that the luminance of the Gd2O2S:Eu3+ nanophosphor screen film increased with an increase in the X-ray energy. Hence, this film would become one of the potential candidate for future imaging applications.
Highlights
Phosphors are well-known materials that exhibit luminescent phenomena when they absorb a certain amount of energy
Gd(NO3)[3], Eu(NO3)[3] and (NH4)2SO4 were weighed in a suitable stoichiometric ratio and were dissolved in a 1:1 mixture of deionized water and ethylene glycol20. 2% w/v of polyvinyl pyrrolidone (PVP) was added to the reaction mixture and vigorous stirred for 2 h
We found that the PL intensity obtained in this study was much higher than obtained by Osseni et al (2011) who prepared Gd2O2S:Eu3+ phosphors for medical applications by precipitating carbonate precursors[36]
Summary
Phosphors are well-known materials that exhibit luminescent phenomena when they absorb a certain amount of energy. Gd2O2S:Tb3+ phosphors are widely used in conventional imaging detectors such as storage phosphors because of their strong green emitting[2]. Silicon detectors coupled with Gd2O2S:Tb3+ phosphors produce images with low sensitivity and poor definition[3]. This is because only 45 – 55 % of the light (λ:500-550 nm) generated by terbium activated phosphor will detected by the silicon and CMOS devices incorporated in x-ray imaging systems due to less sensitive towards green light[4]. It is well known that silicon based photodetectors more sensitive to longer wavelength ranges and red-emitting Gd2O2S:Eu3+nanophosphors should be of interest to investigate
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