Swift heavy ion induced structural, iono and photoluminescence properties of β-CaSiO₃:Dy³⁺ nanophosphor.

Prof C.N.R. Rao Centre for Nano Research (CNR), Tumkur University, Tumkur 572 103, India.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy (Impact Factor: 1.98). 03/2012; 93:300-5. DOI: 10.1016/j.saa.2012.03.013
Source: PubMed

ABSTRACT CaSiO(3):Dy(3+) (1-5 mol%) nanophosphors have been prepared by a low temperature solution combustion method. The structural and luminescence (ionoluminescence; IL and photoluminescence; PL) studies have been carried out for pristine and ion irradiated samples. The XRD patterns of pristine sample show a prominent peak at (320) for the monoclinic structure of β-CaSiO(3). Upon ion irradiation, the intensity of the prominent peak is decreased at the fluence of 7.81 × 10(12)ions cm(-2) and at higher fluence of 15.62 × 10(12)ions cm(-2), the prominent peak completely vanishes. The decrease in peak intensity might be due to the stress induced point defects. On-line IL and in situ PL studies have been carried out on pelletized samples bombarded with 100 MeV Si(7+) ions with fluences in the range (7.81-15.62)×10(12)ions cm(-2). The characteristic emission peaks at 481,574, 664 and 754 nm recorded in both IL and PL are attributed to the luminescence centers activated by Dy(3+) ions. It is found that IL and PL emissions intensity decreases with increase in Si(7+) ion fluence. The decrease in intensity can be due to the destruction of Si-O-Si and O-Si-O type species present on the surface of the sample. FTIR studies also confirm the Si-O-Si and O-Si-O type species observed to be sensitive for swift heavy ion (SHI) irradiated samples.

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    ABSTRACT: The effect of 120 MeVAg9? ion irradiation on the structural, optical and luminescence properties of NaSr1-xBO3:xDy3? (x = 0.5–2.5 mol%) phosphor synthesized by the conventional solid state reaction route is reported. The samples were irradiated with Ag9? swift heavy ions (SHIs) using fluences of 1 9 1012, 5 9 1012 and 1 9 1013 ions cm-2. The unirradiated as well as irradiated samples were characterized by powder X-ray diffraction (PXRD), diffuse reflectance (DR) and photoluminescence techniques. PXRD confirms no change in the phase after irradiation except that loss of crystallinity had been observed which may be due to the fragmentation caused by the SHI. A blue shift in the absorption band of the DR was observed, resulting in an increase in the band gap from 5.61 eV to 5.77 eV, after ion irradiation. An increase in photoluminescence intensity (excited at 385 nm) was observed with increased ion fluences. The ratio of the blue to yellow emission peaks (I483/I577) was calculated and found to be varying with ion fluences suggesting that the white light can be achieved by tailoring this yellow to blue ratio. The Commission Internationale de l’Eclairage coordinates were calculated and found to move toward the white region after irradiation.
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