Electrical and dielectric properties of meridional and facial Alq_3 nanorods powders

摘要

The tris (8-hydroxyquinoline) aluminum (Alq_3) material has attracted a lot of attention from researchers due to its unique properties for the fabrication of organic light-emitting diode (OLED) and display systems. Herein, the crystal structure's effects, i.e., meridional (mir) and facial (fac) isomers' structure on its electrical and dielectric properties, were examined. Firstly, mir-Alq_3 nanorods powders were prepared using the facile solution method without adding surfactant. Then, fac-Alq_3 nanorods powders were prepared by annealing the mir-Alq_3 at a temperature of 410 °C. The morphological, structural, thermal, and optical properties of the prepared Alq_3 samples were investigated. The electrical and dielectric properties were then studied in a temperature range of 20-350 °C in the applied electrical frequency range of 500 Hz-A MHz. The results revealed that mir and /ac-Alq_3 nanorods powders were obtained with diameters of 81 and 94 nm, respectively. The electrical and dielectric results showed that both isomers' nanorods powders were stable up to the temperature of around 200 °C. Besides, the electrical conductivities of mir and fac-Alq_3 nanorods powders were found to increase linearly with increase the frequency. Moreover, the mir-Alq_3 nanorods powders showed higher electrical conductivity than their counterparts with the fac-Alq_3 nanorods powders. In contrast, the fac-Alq_3 nanorods powders showed better dielectric constants and dielectric losses properties than those of the mir-Alq_3 nanorods powders. Both mir and fac-Alq_3 nanorods powders showed decreased dielectric constants and dielectric losses with increased frequency, particularly at the higher temperature. The study concluded that the isomer structure's change could change the electrical and dielectric values without changing the general behavior. These findings could be utilized to improve the fabrication of the Alq_3-based OLED.