| 초록 |
In recent years, power conversion efficiency (PCE) of organic solar cells (OSCs) has increased and reached up to 16% for the single-junction structure. However, many issues of efficiency and stability of bulk heterojunction OSCs are still controversial. In particular, the optimization of the film morphology is very important for high performance and long-term stability because the device efficiency is determined by the three-dimensional structure in the donor-acceptor blended system. In this study, we fabricated the slot-die coated OSCs by introducing water as an unusual additive. Furthermore, we confirmed that the bulk heterojunction morphology and device performance depend on the quantity of water introduced in active solution. The changes by water addition were analyzed by using UV-Vis absorption, AFM, TEM and 2D GIWAXS measurements. As a result, 13% (ref-1; PTB7-Th:IDTBR) and 26% (ref-2; PTB7-Th:PCBM)-improved PCEs compared with as-cast cells were achieved from the water addition. |
