Synthesis of ZnQ_2, CaQ_2, and CdQ_2 for application in OLED: optical, thermal, and electrical characterizations

摘要

Abstract In this study, zinc, calcium and cadmium based organometallic complexes were synthesized as fluorescent materials for the application in organic light-emitting diodes (OLEDs). The crystal structure of ZnQ2, CaQ2, and CdQ2 complexes was determined applying X-ray diffraction. The synthesized complexes were characterized using visible and ultraviolet (UV–Vis), Fourier transform infrared (FT-IR), thermal gravimetric analysis (TGA), and photoluminescence (PL) spectroscopy analysis. The energy levels of Zn, Ca, and Cd complexes were determined by cyclic voltammetry measurements. Heat-treatment was carried out under nitrogen atmosphere at the temperature determined by thermo-gravimetric analysis. TGA results indicated that the complexes with initial decomposition temperatures more than 260 °C had high thermal stability. The ZnQ2 complex has also a maximum temperature in 527 °C with Mres= 55% which is the highest values among three complexes. Further structural elucidation was carried out using FT-IR in which the stretching frequencies of ZnQ2, CaQ2, and CdQ2 bonds were determined. The maximum green photoluminescence at 565, 523, and 544 nm were observed from ZnQ2, CaQ2, and CdQ2 powders, respectively. Comparing fluorescence data results showed that the intensity fluorescence of ZnQ2 and CdQ2 was reduced in comparison with the fluorescence of CaQ2. The optical, thermal and electrical properties of ZnQ2, CaQ2, and CdQ2 powders were evaluated for possible application in organic light emitting devices.