Optoelectronic Properties of α-MoO₃ Tuned by H Dopant in Different Concentration

The optoelectronic properties of layered α-MoO₃ are greatly limited due to its wide band gap and low carrier concentration. The insertion of hydrogen (H) can effectively tune the band structure and carrier concentration of MoO₃. Herein, first-principles calculations were performed to unravel the physical mechanism of a H-doped α-MoO₃ system. We found that the modulation of the electronic structure of H-doped MoO₃ depends on the doping concentration and position of the H atoms. It was found that the band gap decreases at 8% doping concentration due to the strong coupling between Mo-4d and O-2p orbits when H atoms are inserted into the interlayer. More interestingly, the band gap decreases to an extreme due to the Mo-4d orbit when all the H atoms are inserted into the intralayer only, which has a remarkable effect on light absorption. Our research provides a comprehensive theoretical discussion on the mechanism of H-doped α-MoO₃ from the doping positions and doping concentrations, and offers useful strategies on doping modulation of the photoelectric properties of layered transition metal oxides.