Elucidating the optoelectronic properties Ag, Au and Pd doped graphene oxide using a DFT approach

This study utilizes density functional theory (DFT) with the Lanl2dz functional to investigate the effect of silver (Ag), gold (Au) and palladium (Pd) metal adsorption on the electronic properties of graphene oxide (GO). The studied structures, which are pristine GO, Ag-GO, Au-GO, and Pd-GO, are labeled as R (reference), X1, X2, and X3, respectively. The geometrical optimization indicates that Au forms a physical bond with a carbon atom on GO with a bond length 2.169 Å. While, the GO exhibited an energy band gap of approximately 2.39 eV, the subsequent adsorption of metals Ag, Au and Pd leads to a decrease in the band gap, with values of 2.07 eV for X1, 2.16 eV for X2, and 2.28 eV for X3. Further analysis reveals significant differences in the electronic properties of the various materials. Compared to the dipole moment of R (~8.66 D), the dipole moment of X1-X3 ranged from 2.55 D to 6.11 D, which is lower. Our study reveals a modification in the charge distribution within the molecules upon metal adsorption. Interestingly, the open circuit voltage (VOC) exhibits a trend where X2 (1.72 eV) > R (1.16 eV) > X3 (0.95 eV) > X1 (0.54 eV). These findings highlight the crucial role of dopant selection in tuning the optoelectronic properties of GO. By carefully choosing dopants, we can optimize the optoelectronic properties of GO, making it suitable for various applications, including solar energy conversion.