| abstract |
The invention aims at providing a photovoltaic device with high photoelectric conversion efficiency. The aim is attained by an electron donating organic material containing a benzothiadiazole compound in which (a) a benzothiadiazole skeleton and an oligothiophene skeleton are contained, (b) a band gap (Eg) is 1.8 eV or less, and (c) the level of the highest occupied molecular orbital (HOMO) is -4.8 eV or less, wherein said benzothiadiazole compound is formed by covalently combining the benzothiadiazole skeleton and the oligothiophene skeleton alternately, the proportion between the benzothiadiazole skeleton and the oligothiophene skeleton is within a range of 1:1 to 1:2 (however, excluding 1:1), and the number of thiophene rings contained in an oligothiophene skeleton is 3 or more and 12 or less. |