Bright-blue organic electroluminescent device based on bis (2-methyl 8-quinolinolato) (triphenyl siloxy) aluminium

Abstract

An organic-luminescent material bis (2-methyl 8-quinolinolato) (triphenyl siloxy) aluminium (III) (SAlq) was synthesized and its electrical and optical properties were studied. The material exhibited high photoluminescence (PL) and electroluminescence (EL). Photoluminescence (PL) spectra recorded at room temperature revealed a broad blue emission peak at 490 nm along with a shoulder at 448 nm. The material was characterized by UV-visible, photoluminescence, electroluminescence and IR spectroscopic methods. The thermal stability of the material was determined using Thermo Gravimetric Analysis (TGA), which suggests that the material is thermally stable up to 300 ^oC. Using the Tauc relation and the absorbance cut-off wavelength at 410 nm, the optical band gap of the material was evaluated to be 3.1 eV. OLEDs were fabricated in the configuration ITO/TPD/SAlq/LiF/Al. The CIE chromaticity was also studied and the coordinates were found to be independent of operating voltage. The devices show typical non-linear diode <i style="">I</i>-<i style="">V</i> characteristics under forward bias with the threshold voltage of 5 V.