A charge separation heterojunction structure which uses a fullerene polymer film as a part of its constituent materials and which may be used to produce a solar cellor a light emitting diode superior in durability, physical properties of electrons and economic merits. The heterojunction structure is such a structure in which an electron-donating electrically conductive high-polymer film and an electron-accepting fullerene polymer film are layered between a pair of electrodes at least one of which is light transmitting. In forming the layers, the fullerene polymer film is identified using in particular the Raman and Nexafs methods in combination so that upper layers are formed after identifying the polymer film.