Aziridine-Functionalized Graphene: Effect of Aromaticity for Aryl Functional Groups on Enhanced Power Conversion Efficiency of Organic Photovoltaic Cells

Publication date: Available online 24 November 2018Source: Journal of Saudi Chemical SocietyAuthor(s): Sanjeev Kumar Ujjain, Rohit Bhatia, Preety AhujaAbstractWe have demonstrated the covalent functionalization of graphene by nitrene chemistry, resulting in highly dispersed aryl azides functionalized graphene. Two different ortho-substituted aryl azides having different aromatic ring (π-conjugation) and ester/anhydride substituent have been synthesized. Further, on thermolysis they undergo [2+1] cycloaddition ensuing in the formation of aziridine adduct with sp2 carbons of graphene. Resulting aryl azide functionalized graphene sheets (f-graphene I & II) are soluble in most common organic (polar and non polar) solvents, facilitating the structural/property characterization and the device fabrication by solution processing. The aziridine linkage modification of the π conjugation and the strong electronic interaction between the f-graphenes and poly (3-hexylthiophene) (P3HT):Phenyl-C61-Butyric-Acid-Methyl Ester (PCBM) has been confirmed by various spectroscopic analysis. The implications of changing the aromaticity of the aryl azides attached to f-graphenes on the P3HT:PCBM bulk heterojunction (BHJ) photovoltaic device are discussed. The solution cast f-graphene I (5%) doped P3HT:PCBM BHJ showed the power conversion efficiency ɳ=1.94(±0.06) %, while f-graphene II (5%) doped exhibited ɳ=2.16(±0.07) % under AM 1.5 illumination (100 mW/cm2), which is found to be more than dou...
Source: Journal of Saudi Chemical Society - Category: Chemistry Source Type: research