| 초록 |
Tin oxide (SnO2) has been used as electron transport layer (ETL) in PSCs owing to its excellent electrical properties such as deeper conduction band, high electron mobility (≈10-3 cm2 V-1 s-1) and high stability. However, SnO2-based planar perovskite solar cells (PSCs) showed lower photovoltaic performances than mesoporous TiO2-based PSCs. To improve the efficiency and stability of PSCs, we employed a zwitterion as an interfacial material. The zwitterion was successfully introduced on the SnO2 surface and formed interface dipoles. These dipoles lowered the work function of SnO2, which is related to built-in potential in PSCs. After careful optimization, the PSCs with zwitterion-modified SnO2 yields a power conversion efficiency of 21.43% for Spiro-OMeTAD hole transport layer (HTL) and 20.5% for Asy-PBTBDT HTL, respectively. Notably, our devices exhibited excellent environmental stability and this finding can provide a new approach for highly stable PSCs. |
