External Electric Field-Induced the Modulation of the Band Gap and Quantum Capacitance of F-Functionalized Two-Dimensional Sc(2)C

[Image: see text] The modulation of electronic properties and quantum capacitance of Sc(2)CF(2) under a perpendicular external E-field was investigated using density functional calculations for the potential application of nanoelectronics and nanophotonics. Sc(2)CF(2) has an indirect band gap of 0.959 eV without an E-field. Furthermore, it undergoes a semiconducting-metallic transition under a positive E-field and a semiconductor–insulator transition under a negative E-field. The application of the negative E-field makes Sc(2)CF(2) have an indirect band gap. Sc-d, F-p, and C-p states are mainly responsible for the significant variation of the band gap. Sc(2)CF(2) under an external E-field always keeps the character of a cathode material under the whole potential. Especially, Sc(2)CF(2) under a negative external E-field is more suitable for the cathode material due to its much smaller |Q(p)|/|Q(n)| with much higher Q(n). The charge analysis is further performed.