G. Mallesham, Shanigaram Balaiah, M. A. Reddy
Jan 23, 2014
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0
Influential Citations
17
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Journal
Photochemical & Photobiological Sciences
Abstract
Six novel anthracene-oxadiazole derivatives, 4a (2-(4-(anthracen-9-yl)phenyl)-5- p -tolyl-1,3,4-oxadiazole), 4b (2-(4-(anthracen-9-yl)phenyl)-5-(4- tert -butylphenyl)-1,3,4-oxadiazole), 4c (2-(4-(anthracen-9-yl)phenyl)-5-(4-methoxyphenyl)-1,3,4-oxadiazole), 8a (2-(4-(anthracen-9-yl)phenyl)-5- m -tolyl-1,3,4-oxadiazole), 8b (2-(3-(anthracen-9-yl)phenyl)-5-(4- tert -butylphenyl)-1,3,4-oxadiazole) and 8c (2-(3-(anthracen-9-yl)phenyl)-5-(3,4,5-trimethoxyphenyl)-1,3,4-oxadiazole) have been synthesized and characterized for use as emitters in organic light emitting devices (OLEDs). They show good thermal stability ( T _d, 297–364 °C) and glass transition temperatures ( T _g) in the range of 82–98 °C, as seen from the thermo gravimetric analysis and differential scanning calorimetric studies. The solvatochromism phenomenon and electrochemical properties have been studied in detail using UV-Vis absorption, fluorescence spectroscopy and cyclic voltammetry. TD-DFT calculations have been carried out to understand the electrochemical and photophysical properties. The spatial structures of 4b and 8c are further confirmed by X-ray diffraction analysis. Un-optimized non-doped electroluminescent devices were fabricated using these anthracene derivatives as emitters with the following device configuration: ITO (120 nm)/α-NPD (30 nm)/ 4a–4c or 8a–8c (35 nm)/BCP (6 nm)/Alq_3 (28 nm)/LiF (1 nm)/Al (150 nm). Among all the six compounds, 8a displays the maximum brightness of 1728 cd m^−2 and current efficiency 0.89 cd A^−1. Furthermore, as an electron transporter, 8a exhibited superior performance (current efficiency is 11.7 cd A^−1) than the device using standard Alq_3 (current efficiency is 8.69 cd A^−1), demonstrating its high potential for employment in OLEDs. These results indicate that the new anthracene-oxadiazole derivatives could play an important role in the development of OLEDs.