First-principles Study Of Gas Molecules Adsorption On Metal Decorated Blue Phosphorene

In this paper,the first-principles calculation method based on density functional theory conbined with Vienna ab initio simulation package(VASP)are used to systematically study the adsorption characteristics of various gas molecules(CO,NO,H2 S,SO2 and NO2)on blue phosphorene.By comparing the energy of the optimized most stable adsorption system,the most stable adsorption structure,the corresponding energy band structure and density of states as well as the charge density difference,the gas sensitivity mechanism of the blue phosphoene-based gas sensor was analyzed.A variety of metal atoms(Li,Al,Fe,Co,Ni,Pd,Ag,Pt)and nonmetal atoms(B,C,Si)are introduced to decorate the blue phosphoene to obtain stronger adsorption ability and higher sensitivity.The results show that CO and NO are difficult to be captured by pure blue phosphoene due to the small adsorption energy,charge transfer and large adsorption distance.In order to find the most suitable transition metal dopants,we calculated the formation energies of multiple doping systems.It was found that the blue phosphoene doped with Fe,Co,Ni,Pd,Ag and Pt have higher formation energies and smaller structural deformation than the blue phosphoene doped with other transition metals.When they are used for the adsorption of CO and NO,although Ag doped blue phosphoene makes the adsorption of CO still maintain physical adsorption,the adsorption energy after doping is much higher than that before doping.The other transition metal atoms such as Fe,Co,Ni,Pd,Pt doped blue phosphoene substrate show strong chemisorption for CO.In terms of NO,the doping of these six transition metal atoms also cause obvious chemisorption.The strong interaction between doped substrates and gas molecules is an important sign that the adsorption ability is improved.Transition metal doping not only brings magnetism to the adsorption system but also achieves the transformation of the whole system from semiconductor to metal.In addition,the increase or decrease of the band gap caused by doping in the adsorption system greatly improves the sensitivity of gas molecules.These unique and excellent properties further indicate that Fe,Co,Ni,Pd,Ag,Pt doped blue phosphoene is easier to detect CO and NO gas molecules.It was found that the sensitivity of pure blue phosphoene to H2 S,SO2 and NO2 molecules is weak.In order to enhance the reaction between them,the blue phosphoene substrate is decorated by Li,Al,Ni and Pt.The decorated system can be used for gas sensing because of its higher binding energy and relatively small structural deformation.The results show that all the decoration configurations have good enhancement effect in adsorption ability,except for H2 S adsorbed Al modified blue phosphoene system.Due to the large adsorption energy,charge transfer and small adsorption distance,the adsorption of H2 S,SO2 and NO2 on metal decorated blue phosphoene belongs to chemisorption,while H2 S adsorbed Li,Al decorated blue phosphoene are excluded.The change of band gap of the most stable adsorption system further proves that metal decorating can improve the sensitivity of blue phosphoene to gas molecules.Different adsorption energies conresponds to different desorption time.Metal decoration can not only change the magnetism of the adsorption system,but also change the essential property of the material.In addition,a single nonmetallic atom B,C,Si doped blue phosphoene and two different nonmetallic atoms 1B1 C,1C1Si,and 1B1 Si doped blue phosphoene can also produce similar results,namely,obtaining strong chemisorption,making the adsorption system magnetic and completing the transition from semiconductor to metal.The change of the work function of the adsorption system indicates that this two doping way can also enhance the sensitivity of blue phosphoene to NO and NO2 molecules.Our current work is conducive to the rapid development of blue phosphoene gas sensors in the future.