| 초록 |
The design of hole transporting materials (HTMs) is important to realize highly efficient and stable perovskite solar cells (PSCs). We synthesized donor−acceptor-type HTMs and fabricated the PSC device with the dopant-free HTM. The resulting PSC device with dopant-free HTM shows a high power conversion efficiency of 17.3%, which is similar with the value of the PSC device with doped spiro-OMeTAD as HTM, and shows much improved device stability. In the stability test under the conditions of 60% relative humidity/1 sun light-soaking without encapsulation, the PSC with the new HTM was found to retain 80% of its initial efficiency over 500 h. We demonstrate the relationship between the conjugation lengths of HTMs and moisture intrusion into the perovskite layer. The relatively large π-conjugated HTM forms denser films, which effectively decrease the spaces between the molecules and retard water intrusion. |
