Synthesis and photovoltaic properties of donor-acceptor oligothiophene derivatives possessing mesogenic properties

摘要

For the purpose of developing novel photovoltaic materials and organic photovoltaic devices with good performance characteristics, 5-cyano-2,2′: 5′,2″-terthiophene (3T-CN) and 5-cyano-2,2′:5′,2″: 5″,2″ ′-tetrathiophene (4T-CN) were synthesized. The 3T-CN and 4T-CN were donor-acceptor oligothiophene derivatives possessing mesogenic properties. The photovoltaic properties of 3T-CN and 4T-CN were studied. The rigid and flexible photovoltaic devices were fabricated using 3T-CN, 4T-CN, and 3,4,9,10-perylenetertracarboxylic dianhydride (PTCDA). The results showed that the -CN group played an important role in increasing short circuit current density (I _(sc)) and power conversion efficiency (PCE). Both rigid device glass-ITO/4T-CN/PTCDA/Al and flexible device PET-ITO (indium tin oxides coated with polyethylene terephthalate)/4T-CN/PTCDA/Al had greater I _(sc) and PCE compared with rigid device glass-ITO/4T/PTCDA/Al. It was possible that the -CN group, with strong electron-withdrawing character, and mesogenic properties of 4T-CN enhanced the efficiency by promoting forward interfacial electron transfer.