Alkali-metal(Li, Na, and K)-adsorbed MoSi_(2)N_(4) monolayer: an investigation of its outstanding electronic, optical, and photocatalytic properties

Single-layer MoSi_(2)N_(4),a high-quality two-dimensional material,has recently been fabricated by chemical vapor deposition.Motivated by this latest experimental work,herein,we apply first principles calculations to investigate the electronic,optical,and photocatalytic properties of alkali-metal(Li,Na,and K)-adsorbed MoSi_(2)N_(4) monolayer.The electronic structure analysis shows that pristine MoSi_(2)N_(4) monolayer exhibits an indirect bandgap(E_(g)=1.89 eV).By contrast,the bandgaps of one Li-,Na-,and K-adsorbed MoSi_(2)N_(4) monolayer are 1.73 eV,1.61 eV,and 1.75 eV,respectively.Moreover,the work function of MoSi_(2)N_(4) monolayer(4.80 eV)is significantly reduced after the adsorption of alkali metal atoms.The work functions of one Li-,Na-,and K-adsorbed MoSi_(2)N_(4) monolayer are 1.50 eV,1.43 eV,and 2.03 eV,respectively.Then,optical investigations indicate that alkali metal adsorption processes substantially increase the visible light absorption range and coefficient of MoSi_(2)N_(4) monolayer.Furthermore,based on redox potential variations after alkali metals are adsorbed,Li-and Na-adsorbed MoSi_(2)N_(4) monolayers are more suitable for the water splitting photocatalytic process,and the Li-adsorbed case shows the highest potential application for CO_(2) reduction.In conclusion,alkali-metal-adsorbed MoSi_(2)N_(4) monolayer exhibits promising applications as novel optoelectronic devices and photocatalytic materials due to its unique physical and chemical properties.