First-principles study on the excellent photovoltaic, photocatalytic and photodetection performance of a new two-dimensional B₂C₆N₄ monolayer

This study systematically investigates the strain-modulated electronic and optical properties of a novel two-dimensional (2D) boron-carbon-nitrogen (B2C6N4) monolayer through first-principles calculations. The optimized BCN structure exhibits an orthorhombic lattice with anisotropic mechanical properties. Phonon dispersion and ab initio molecular dynamics simulations confirm dynamic and thermal stability under ambient conditions. The B2C6N4 monolayer possesses a indirect bandgap of 1.31 eV, with valence and conduction band edges straddling water redox potentials, enabling photocatalytic hydrogen evolution and oxygen production. Strain engineering (−3% to +3%) induces bidirectional bandgap modulation (1.18–1.46 eV), accompanied by shifts in band edge positions aligned with the Shockley-Queisser optimal range for photovoltaics. Anisotropic carrier mobility is observed, with electron mobility exceeding 4815 cm²/V/s along specific crystallographic directions. Polarization-dependent optical absorption reveals strong visible-light and ultraviolet responses. These findings position the BCN monolayer as a promising candidate for flexible optoelectronics, adaptive photocatalysis, and strain-engineered solar cells