Tunable electrochemistry with moiré flat bands and topological defects at twisted bilayer graphene [article]

Yun Yu, Kaidi Zhang, Holden Parks, Mohammad Babar, Stephen Carr, Isabel Craig, Madeline Van Winkle, Artur Lyssenko, Takashi Taniguchi, Kenji Watanabe, Venkatasubramanian Viswanathan, D. Kwabena Bediako
2021 arXiv   pre-print
Tailoring electron transfer dynamics across solid-liquid interfaces is fundamental to the interconversion of electrical and chemical energy. Stacking atomically thin layers with a very small azimuthal misorientation to produce moir\'e superlattices enables the controlled engineering of electronic band structures and the formation of extremely flat electronic bands. Here, we report a strong twist angle dependence of heterogeneous charge transfer kinetics at twisted bilayer graphene electrodes
more » ... h the greatest enhancement observed near the 'magic angle' (~1.1 degrees). This effect is driven by the angle-dependent tuning of moir\'e-derived flat bands that modulate electron transfer processes with the solution-phase redox couple. Combined experimental and computational analysis reveals that the variation in electrochemical activity with moir\'e angle is controlled by atomic reconstruction of the moir\'e superlattice at twist angles <2 degrees, and topological defect AA stacking regions produce a large anomalous local electrochemical enhancement that cannot be accounted for by the elevated local density of states alone. Our results introduce moir\'e flat band materials as a distinctively tunable paradigm for mediating electrochemical transformations.
arXiv:2108.06826v1 fatcat:blkasl2nune4hda3627kaw2coa