Highly enhanced optical absorption in visible region: A theoretical insight into N-doped SnP3 hydrogen evolution catalyst

Nitrogen doping is an efficient and practical method for material engineering. Here, we use the density functional theory (DFT) calculations to exhibit the improvement of the electronic and optical properties of nitrogen doped on SnP3 monolayer. The stability of N-doped SnP3 monolayers have been examined via formation energies, phonon spectrums and ab initio molecular dynamics simulations, the results indicate that the systems with high nitrogen concentration even have better stability. The optical absorption of SnP3 monolayer can be significantly enhanced after nitrogen doping, which leads to the absorption coefficient in the visible zone strengthened to be as three and five times as that of the pristine SnP3 and MoS2 monolayers on the order of 105cm−1, respectively. The band alignment under HSE06 implies that the doped-SnP3 monolayer can conduct the hydrogen evolution reaction with the conduction band minimum localized more positive than the reduction potential. The band gap of SnP3 monolayer can be effectively modulated by changing the nitrogen concentrations or applying an external strain or electric field, illustrating its appealing application in next-generation optoelectronics. Overall, our contribution provides predictions on the optoelectronic and photocatalytic performances of the pristine and N-doped SnP3 monolayers, which indicates the applications in the fields of novel nano-electronic devices and photocatalysts for water splitting reactions. •N-doped SnP3 monolayers are the photocatalysts for HER with ultra-high infra-red and visible light absorption.•The N-doped SnP3 monolayers have direct band gap at the composition of 12.50%, 15.63%, 21.88%, 25.00% and 37.50%.•The electronic properties can be effectively engineered by external strain and electric field.•Nitrogen doping is environmental friendly.