Red/NIR-absorbing oligothiophenes for organic solar cells

Abstract

By introducing various donor and acceptor functions into oligothiophenes, tailored low band gap materials with intriguing properties meeting the requirements for application in "small molecule" organic solar cells were developed and photovoltaic devices with efficiencies as high as 3.2 % were fabricated. In the conjugated systems, thienothiadiazole, thienopyrazine, benzothiadiazole, thiadiazolo pyridine, dicyanovinyl, and trifluoroacetyl were incorporated as acceptor units, to obtain red/near-IR absorbers with band gaps as low as 1.2 eV in thin films.