A New Effective Approach to Prevent the Degradation of Black Phosphorus: The Scandium Transition Metal Doping

Abstract

Density functional calculations are used to investigate the effective approach to prevent the degradation of black phosphorus (BP). For the few-layer BP, it is found that the Sc atom monodoped the 3 × 3 unit cell with a doping ratio of 1.4%, which can retain the semiconductor character with a moderate band gap (Egap) of 0.84 eV. Obviously, the two layer BP(2MLBP) with one Sc atom binding to three P atoms on the upmost layer has the lowest formation energy (−4.57 eV), exploring its greatest stability. Moreover, the calculated binding energy of Sc above the three P atoms is the largest (4.24 eV) energy, which is larger than the experimental cohesive energy of bulk Sc (3.90 eV), indicating that the clustering of Sc atoms on the surface of BP can be avoided. Importantly, the Sc atom adsorbed 2MLBP structure (2MLBP-Sc) has a conduction band minimum (CBM) value of −4.18 eV, which is below the redox potential of O2/O2– (−4.11 eV). When the O2 molecule is adsorbed on the 2MLBP-Sc, although the Sc–O and O–P bonds ...