| 초록 |
Cs2SnI6 has emerged as a promising lead-free perovskite in the optoelectronics field, however, its charge transfer kinetics remain unclear. Here, we report the charge transfer mechanism of Cs2SnI6 via its surface state. Specifically, charge transfer through the surface state of Cs2SnI6 and its subsequent surface state charging are demonstrated by cyclic voltammetry and Mott–Schottky measurements, respectively. Because it is expected that the surface state of Cs2SnI6 is capable of regenerating oxidized organic dyes, a Cs2SnI6-based regenerator is developed for a dye-sensitized solar cell. Consequently, Cs2SnI6 shows efficient charge transfer with a thermodynamically favorable highest occupied molecular orbital of the dyes, achieving a 79% enhancement in the photocurrent density compared with that of a conventional liquid electrolyte. Our results suggest that the surface state of Cs2SnI6 is the main charge transfer pathway and should be considered in designs of Cs2SnI6-based devices. |
