Syntheses, characterization and photostability studies of n-type semiconductor materials

Synthesis of air-stable and moisture-resistant organic semiconducting materials is the key to the development of next generation flexible optoelectronics such as organic light emitting diodes (OLEDs) and organic photovoltaic devices (OPVs). One of the important applications of organic semiconductor materials is in OLEDs. Although, green and red light emitting materials are comparatively well developed in terms of brightness, efficiency, and lifetime of the device; development of stable and high efficient blue light emitting materials remains challenge. Anthracene is one important aromatic pi-conjugated blue light emitting material well studied for OLED applications. Although anthracene have good electroluminescent and electron transporting properties, it is more susceptible to oxidation at 9,10-position of the ring in presence of oxygen, moisture, and light, such oxidation decreases device stability and efficiency. Perfluoroalkylation of anthracene is an effective method to improve air stability. Introduction of strong electron withdrawing perfluoroalkyl groups on anthracene core lowers both LUMO and HOMO thereby reduces chances of oxidation and improves electron injection. Perfluoroalkylation of anthracene involves simple copper mediated cross coupling reaction between perfluoroalkyl iodide and brominated anthracene.;We successfully synthesized and characterized perfluoroalkylated anthracene derivatives which exhibit enhanced blue light emission as well as increased fluorescence quantum yields. Photostability studies of perfluoroalkylated anthracene derivatives were carried out to know the stability of the molecules in presence of light and air. These studies can be used as a model to determine the perfluoroalkylation effect on material stability for organic solar cells.