| 초록 |
In planar perovskite solar cells, compact TiO2 is widely used as an electron transport layer (ETL). However, TiO2-based planar-perovskite solar cells exhibit low performance due to the unsuitable conduction band energy and low electron extraction ability. Herein, the planar TiO2 ETL of perovskite solar cells is modified with CuI via a simple one step spin coating process. The p-type nature of the CuI islands on the TiO2 surface leads to modification of the TiO2 band alignment, resulting in barrier free contacts and increased open-circuit voltage. It is found that the polarity of the CuI-modified TiO2 surface can pull electrons to the interface between the perovskite and the TiO2, improving electron extraction and reducing nonradiative recombination. The optimized device shows a high efficiency of 19.0%. In addition, the optimized device shows negligible hysteresis. These results demonstrate the hitherto unknown effect of p-type ionic salts on electron transport material. |
