[20p-231C-1~9] Frontier of organic semiconductor crystals: Toward the Molecular Science of Quantum Liberated Electrons

[20p-231C-5] Effect of the molecular orientation of PC₆₁BM on performance of organic photovoltaics

〇Kouki Akaike¹, Takumi Kumai¹, Kyohei Nakano², Hiroyuki Yoshida^3,4, Keisuke Tajima², Kaname Kanai¹ (1.Tokyo Univ. of Sci., 2.RIKEN CEMS, 3.Grad. School of Eng. Chiba Univ., 4.Mol. Chirality Res. Cent., Chiba Univ.)

Keywords:molecular orientation, fullerene acceptor, donor/acceptor interface

We investigated the effects of PC₆₁BM’s orientation on ITO/PEIE/PC₆₁BM/6T/MoO_x/Al structured OPVs, where the orientation of PC₆₁BM was controlled by thermal annealing. When 6T contacts with the side chain of PC₆₁BM, V_OC increases by a factor of 1.4 in comparison to the direct contact of 6T with C₆₀ backbone of PC₆₁BM. The multiple analyses with photoelectron spectroscopy, electroluminescence, and external quantum efficiency suggest that the energy of the charge transfer states increases in such an interfacial geometry and carrier recombination is suppressed by the presence of the side chain of PC₆₁BM at the donor/acceptor interface.