EXPERIMENTAL AND THEORETICAL ANALYSIS OF SOLVATOCHROMISM IN ORGANIC DYES

Abstract

ihe synthesis and the structure-property of 5,6-functionalized benzothiadiazole (BT) and benzirnidazole (BI) are highly desirable to explore these moieties more in the held of organic electronics, in this regard we designed and synthesized benzothiadiazole and henzimidazole based small bipolar molecules VI-V4 featuring 5.6-functionazation of BTIBl unit by carbazole and triphenylamine donors. The BT dyes exhibited red shifted absorption due to intramolecular charge transfer transtion than that of Bl-dyes. The solvatochromic studies were carried out to expose the nature of ground and excited state of the dyes. The polar excited states for the BT-dyes were responsible for the less quantum yield in DCM as compare to the BI-dyes. The Lippert-Mataga and E1 (30) plots revealed the highest polar nature for the dye V2 featuring triphenylamine and BT moieties. The electrochemical study showed low oxidation potential for triphenylamine based dyes V2 and V4 and multi oxidation potential for the carbazole based dyes Vi and V3. The thermo gravirnetric analysis for the dyes revealed high decomposition temperature (Td) in range of 689-820 °C. Moreover, these newly synthesized dyes open new class of emitters for fabrication of OLEDs and other electronic devices.