Enhanced quantum capacitance in Ti, V, Cr, Fe, Ga, Ge, Se, and Br doped arsenene: A first principles investigation

Abstract

The present work systematically studied the quantum capacitance in 3d (Ti, V, Cr, Fe) and 3p (Ga, Ge, Se, Br) doped Arsenene using first-principles calculation. The calculated negative formation energy (EF) advocates the feasibility of such doping, with a large EF for 3d-Arsenene. Among the dopants, Ti was strongly embedded within the vicinity of the thinned monolayer. The HOMO-LUMO analysis confirms a strong interaction between the Ti-3d state and the Arsenene 4p-state. More importantly, semiconducting states resulted on Ti/Ga/Ge/Br doping, whereas metallic states took place from V/Cr/Fe/Se doping. Projected density of state (PDOS) also advocates these observations and predicts the 3d-state to play an important role in calculating the quantum capacitance (CQ) of 3d-Arsenene. It is found that 3d/4p doping significantly enhanced the quantum capacitances (CQ)/surface charges (Q) of Arsenene. Among 3d and 4p doping, Cr-Arsenene and Se-Arsenene, respectively, have the highest CQ of 345 µF/cm2 and 176 µF/cm2 in the positive and negative bias region, respectively. The finding recommends Cr and Se-doped Arsenene for asymmetric supercapacitors as anode and cathode materials, respectively. Also, Ti/V/Fe/Ga/Ge/Br-Arsenene show enhanced CQ and surface charge (Q), making them suitable for supercapacitor applications.