Effects of X-ray irradiation on the structural and optical properties of microcrystalline Alq3 powder and its potential dosimetry application

Tris-(8-hydroxyquinoline) aluminum (Alq3) is a well-known organometallic compound due to its numerous applications in electronic devices including organic light-emitting diodes, photodiodes, and optoelectronics. It has unique optical properties; however, the effect of ionizing radiation on its properties has not been investigated to date. In this study, Alq3 microrods were pressed into small pellets, annealed at 150 degrees C for 1 h and then exposed to X-ray radiation at different doses in the range of 5-20 Gy. Subsequently, their structural and optical properties were analyzed by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and photoluminescence (PL) emission spectroscopy. XRD results showed a slight shift in the positions of the Alq3 peaks, with no significant change in the crystallinity or phase of Alq3, whereas the intensity of the Raman and FTIR peaks of these pellets systematically decreased upon irradiation. The intensity of the PL band of Alq3 at 510 nm initially increased to about three times higher than the unirradiated PL signal under 10 Gy irradiation and then started to decrease. The observed decreases in the intensities of the Raman and FTIR peaks are attributed to the slow/gentle degradation of Alq3, particularly to the breakage of its C-H, C-O, and Al-O bonds. In addition, the linear dose response of Raman and FTIR signals present a nearly excellent dose dependence with a minimal percentage error of 1% and 4%, respectively. These results might serve as a basis for the further investigation of Alq3 microrods as a radiation dosimeter. In particular, the observed systematic modifications in the optical properties of Alq3 and the resulting excellent linear response curves of irradiation doses verses signal intensities are quite encouraging.

Automated summary

Tris-(8-hydroxyquinoline) aluminum (Alq3) is a well-known organometallic compound with various applications in electronic devices. When exposed to X-ray radiation, the structural and optical properties of Alq3 undergo changes, showing potential for use as a radiation dosimeter. The observed systematic modifications in the optical properties and the excellent linear response curves of irradiation doses verses signal intensities are quite encouraging for further investigation.