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 braking means includes a sliding contact member in sliding contact with end surface of the rotating spool, a coil spring urging the sliding contact member in shaft direction of the spool, and a rotation restriction means for restricting rotation of the sliding contact member. The bonding material is resistant to halogen-containing plasmas and exhibits desirable mechanical properties.