Organic photovoltaic devices with high open-circuit voltage based on oligothiophene derivatives

For the purpose of developing organic photovoltaic devices with good performance characteristics, we have fabricated two devices using 4T-CHO, 5T-CHO and PTCDA. The ITO/4T-CHO/PTCDA/Al device has a Voc of 2.45 V and photoelectric conversion efficiency of 2.76%. The ITO/5T-CHO/PTCDA/Al device has a Voc of 2.1 3V and photoelectric conversion efficiency of 2.90%. The two devices have higher Voc (2.45 and 2.13 V). It is possible that intermolecular hydrogen bonding between CHO group of nT-CHO and carboxylic dianhydride of PTCDA contribute to enhance the efficiency by promoting interfacial electron transfer and eliminating the subconducting band trap sites.