| 초록 |
Photovoltaic performance of organic solar cells (OSCs) highly depends on the anisotropy of optoelectronic properties of organic materials. In this study, we focus on the influence of interfacial donor-acceptor molecular orientation on photocurrent generation. Planar heterojunction solar cells with orientation-controlled conjugated polymer layers are fabricated and analyzed. The orientation of polymer molecules is modified by controlling solvent evaporation during spin-coating process. The polymer layers show similar optical and electrical properties regardless the orientation. However, the photocurrent generation is more efficient in the device with face-on donor-acceptor interface. Photophysical analyses reveal that the molecular orientation affects the separation of bound charge pairs at the interface, resulting in enhanced formation of free charges in the case of face-on interface. These results emphasize the importance of molecular orientation control for high performance of OSCs. |
