Theoretical Prediction Of Surface Modification And CO Adsorption On Phosphorene

The successful fabrication of phosphorene which is the novel two-dimensional material greatly inspired particular interests and arguments.Except the high surface-to-volume ratio of graphene and TMDCs,phosphorene also has other excellent properties,such as the indirect band-gap absent in graphene,high hole mobility and large on-off ratio.These unique characterisitics make black phosphorene become the focus of two-dimensional materials research.Moreover,phosphorene might replace silicon as graphene and become the new generation of seimiconductor.In this work,the DFT calculations are performed using the Vienna Ab-initio Simulation Package(VASP)to investigate the properties of phosphorene.Because of the instability of phosphorene for gas adsorption,we find doping and vacancies could enhance the surface activity of phosphorene and strengthen the CO adsorption.Therefore,our main research subject is metal doped phosphorene and the electronic properties changing by CO adsorption.The specific research contents are as follows:(1)For Co-BP-CO and BP-CO,the energy band of phosphorene will change greatly by surface modification.The band gap of bP-Co experiences direct-to-indirect transition after CO molecule adsorption.Promotion of CO adsorption is also proved by the coupling effect between Co atom and CO molecule.Compared with BP-CO,Co-BP-CO has a larger combine energy which means better stability.In addition,we found the charge transfer between CO and Co-BP by Bader analysis which is much more than the one between CO and pristine phosphorene.Consequently,the sensitivity and selectivity of CO gas on phosphorene could be improved by Co doping.(2)Co doping proves that the metal atom at the surface of phosphorene could modifies the properties positively and strengthen the tenability of electronic configuration.After the whole calculation of metal doped phosphorene,alkali metal doping could change the optical properties of phosphoene.The noble metal Pd and Pt have a strong SMSI effect with phosphorene,which is help for improving the catalytic performance.Fe-BP,Co-BP and Ni-BP has a relatively large combine energy among the metal.Fe-BP and Ni-BP also perform an intense magnetization.The electronic properties of Pb-BP could be tuned by an external electric field.For CO adsorption,the band gap of Li-BP-CO and Al-BP-CO experiences indirect-to-direct transition.Pd-BP-CO,Pt-BP-CO,Ni-BP-CO and Al-BP-CO show a great metallicity and stability.There is a large charge transfer between CO and doping structure.This also proves the enhanced detection and adsorption of CO gas by metal doping.(3)Considering the defects of phosphorene in actual fabrication,six di vacancy defects structure,D1-2,D1-3,D1-4,D1-5,D1-6 and D1-8,was estabilished by permutation and combination to avoid repeating configuration.Formation energy of divacancy phosphorene which is more stable than single vacancy structure owing to the smaller formation energy.Due to the change of defect points,deformation of P-P bond will affects the physical and electronic properties indirectly.Results show that the second P atom can easily come out of phosphorene when the first P atom was removed.Besides,foreign atoms in phosphorene were increased by doping.The electronic properties of doping systems is analyzed based on divacancy.With Co atom replaced the P1 and P5,D1-5 is the most stable structure.Results imply that increasing of Co atom could improves the CO adsorption on phosphorene.More CO adsorption could cause band gap decreasing and leads to the transformation from semiconductor to metal.