Optical Absorption and Second-Harmonic Generation in Violet Phosphorene: Experimental and Theoretical Aspects

The better thermal stability and extremely high deformation resistance of violet phosphorene make it a great potential candidate to be a new "dream material" better than black phosphorene. Due to the high confinement of 2D materials, violet phosphorene is expected to possess extraordinary optical properties. Herein, the linear and nonlinear optical properties of violet phosphorene are discussed by both theoretical simulation and experimental measurement. The fibrous nature with twofold rotation symmetry tends to the non-centrosymmetric crystal structure, leading to the lower dipole transition possibility in violet phosphorene, but the intensive flatness of its electronic bands produces a larger joint density of states, finally resulting in better linear absorption than for black phosphorene. In addition, the intrinsic non-centrosymmetric crystal structure causes the nonlinear second harmonic generation in violet phosphorene, showing its potential in nonlinear optics.