X-RAY LUMINESCENT COMPOSITES BASED ON POLYCRYSTALLINE DIAMOND WITH INTEGRATED NAGDF4:EU NANOPARTICLES FOR PHOTONICS

Abstract

The luminescent diamond composite with high-intensity narrow-band X-ray luminescence at a wavelength of 612 nm with 6.2 nm width at half-height was developed. In the luminescence spectra of composites, compared with the initial powders, there are no transitions with 5D1 and 5D0–7F4 transitions. The ratio of line intensities between the 5D0–7F1 and 5D0–7F2 transitions has changed. In the composite, the intensity of the induced electric dipole transition of 5D0–7F2 with respect to the intensity of the magnetic dipole transition of 5D0–7F1 was much larger than in the initial powder. This was indicated about a decrease in the local symmetry of the Eu3+ ions environment in the composite. The positions and intensities of individual lines in the 5D0–7F2 transition had changed markedly in the composite, in particular, the most intense line of this transition has shifted from 616 to 612 nm. This was indicated as a change in the structure of NaGdF4: Eu upon composite production. X-ray luminescence spectra of a composite with different amounts of dispersed droplets were showed that the sample with 3 droplets of dispersion with a total concentration of applied particles of 96 mg/ml was exhibited the most intense luminescence. A sample with a 65 mg/ml total concentration (1 drop of dispersion) slightly exceeds the intensity of the sample with a total concentration of 64 mg/ml (2 drops of dispersion). The lowest intensity was recorded for a sample with a 32 mg/ml total concentration (1 drop of dispersion). The concentration dependence of the intensity of X-ray luminescence from the number of dispersed particles was noted. The use of β-NaGdF4: Eu nanopowders instead of europium oxide and europium fl uoride made it possible to obtain high-intensity luminescence with a higher aspect ratio of signal-to-noise ratio than previously published by various authors. The possibility of using a fl uorescent diamondfl uoride composite as a X-ray luminescent screen has been shown for the fi rst time.

Keywords

• sodium-gadolinium fl uoride
• polycrystalline diamond
• X-ray luminescent composites.