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 (E gap ) 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 O 2 /O 2 − (−4.11 eV). When the O 2 molecule is adsorbed on the 2MLBP-Sc, although the Sc−O and O−P bonds are formed based on the breaking of the O−O bond, forming the 2MLBP-Sc-2O structure, this contains the intact 2MLBP. Importantly, the 2MLBP-Sc-2O structure has a direct E gap of 0.32 eV with a CBM of −4.75 eV which is far below the redox potential of O 2 /O 2 −; therefore, its E gap is not located in the range of visible light, indicating that it is a good direct semiconductor and stable in the air. When the structure further interacts with the H 2 O molecule, the resulting 2MLBP-Sc-2O−H 2 O structure can maintain its integrity during the dynamics course. Our research can supply a new effective method to protect the BP under illumination and in oxygen and water environments.

Black phosphorus electronics

“…Besides, transition metals such as copper, silver, scandium etc. also can be utilized in the doping of BP [51,56,57]. Among them, Ag and Sc are often utilized to protect BP from ambient degeneration with a slight change in its electrical performance [49,53].…”

Potential of Black Phosphorus in Immune‐Based Therapeutic Strategies

“…Moreover, utilizing a transition metal, Sc doping also can bind to three P atoms on BP to form BP-Sc. Although the BP-Sc-2O structure is formed when BP is exposed to air, the redox potential of O2/O2 − (-4.11 eV) still exceeds the CBM of BP-Sc-2O (-4.75 eV), which contributes to its stability [ 63 ]. In addition to metal elements, Lv et al also reported that the CBM of nonmetallic element S-doped BP was below the redox potential of O 2 /O 2 − , which prevented the oxidative degradation of BP in ambient conditions [ 64 ].…”

Heteroatom‐Doped Black Phosphorus and Its Application: A Review

“…Transition metal (TM) doping is another effective method to adjust the electronic structure of BP. [ 32‐38 ] Hashmi et al . studied the electronic structure and magnetic properties of various transition metal (TM) doped phosphorene by changing the TM impurity dopants in the substitutional site.…”