First-principles investigations of two-dimensional pentagonal borides
Finding new materials with specific applications has always been a fascinating topic in the development of two-dimensional(2D)materials.In this work,three 2D borides with pentagonal structure are predicted by density functional theory(DFT)calculation,namely penta-B4X2(X=S,Se,Te).The results show that all three B4X2 structures show good thermodynamical,dynamical,thermal and mechanical stability.Structurally,the coexistence of B—X and B—B covalent bonds in the penta-B4X2 structure contributes to the structural stability of the pentagonal framework.In addition,all three monolayer structures have high in-plane Young's modulus(with a minimum value of 90.67 Nm-1),among which the 2D penta-B4Se2 monolayer has a negative Poisson's ratio(NPR)in a specific in-plane angular direction.The electronic band structures indicate that all pentagonal monolayers are semiconductors with moderate bandgaps(1.04,1.17,1.28 eV).It is worth noting that the three types of 2D penta-B4X2 have strong absorption coefficients for different wavelengths of light waves,up to an order of 3.5×105 cm-1 in the visible region,and in the ultraviolet region they exhibit stronger light absorption ability.The excellent light absorption performance makes the 2D penta-B4X2 structures promising candidates for photocatalyzing water splitting.This work not only predicts three new 2D pentagonal borides,but also identifies their promising applications in semiconducting devices,nanoelectronics,photoelectronics and photocatalytic water splitting.
two dimensional boridesfirst principles calculationstructure and stabilitymechanical propertieselectronic structureoptical properties
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维普
