| 초록 |
We developed dithieno[3,2-b;2′,3′-d]thiophene (DTT)-based organic sensitizers for high-performance thin photoactive TiO2 films (~1- μm) by the introduction of single (S-DAHTDTT), double (D-DAHTDTT) and triple bond (T-DAHTDTT) between the electron donor and the conjugated DTT π-bridge. As a result, with only 1.3-μm transparent and 2.5-μm TiO2 scattering layers, the triple bond sensitizer (T-DAHTDTT) shows the highest power conversion efficiency (η = 8.4%; VOC = 0.73 V, JSC = 15.4 mA·cm−2 and FF = 0.75) in an iodine electrolyte system under one solar illumination (AM 1.5, 1000 W·m−2). In this study, we suggests that the triple bond can increase the performance of DSC with a thin photoactive film by enhancing not only JSC through improved ICT, but also VOC through the evenly distributed sensitizer surface coverage. We analyzed these correlation mainly in terms of charge injection efficiency, level of photo-charge storage, and charge transport kinetics. |
