Comparative analysis of the substitutional and interstitial Li-, Na-doped, and Li∖Na-Codoped Cu2O via density functional calculations

A comprehensive comparative study utilizing HSE06 and GGA density functional calculations was conducted to investigate the impact of Li and Na doping, as well as their co-doping, on the physical properties of cuprous oxide (Cu 2 O). This study examined three possible structures, including substitution of Li, Na, and Li/Na for Cu, and interstitial Li, Na, and Li/Na in both tetrahedral and octahedral sites. The results of the study revealed that the introduction of alkaline atoms leads to structural changes in Cu 2 O, and the degree of lattice parameter extension or compression varies across different doping sites. Additionally, the study provided an estimation of the enthalpies of formation for pure and doped-Cu 2 O, which is useful in understanding the stability of the systems. Notably, the study found that Li, Na, and Li/Na-doped-Cu 2 O were more readily formed in substitutional sites rather than in interstitial sites. The findings also indicate that substitutional doping and co-doping exhibit a large band gap while maintaining the properties of a p-type semiconductor, while interstitial doping and co-doping of Cu 2 O led to significant absorption enhancement and n-type conductivity characteristics. These results provide new insights into the structural and electronic properties of Cu 2 O, with the findings suggesting that interstitial doping of Li and Na could be a promising approach for improving the absorption of visible light in Cu 2 O-based solar cells, thus contributing to the development of more efficient and cost-effective photovoltaic devices.