Optical properties of Ta-doped Tio2 as a solar cell active layer using first-principles calculation

• Main Authors: Qibtiya, Mariya Al, Mulyanti, Budi, Fathurrahman, Fadjar, Wulandari, Chandra, Nurhidayatulloh, Nurhidayatulloh, Pawinanto, Roer Eka, Hasanah, Lilik, Hamidah, Ida, Majlis, Burhanuddin Yeop
• Format: Conference Proceeding
• Language: English
• Subjects: Anatase; Density functional theory; Electron states; Electronic structure; Energy gap; Excitons; First principles; Functionals; Optical properties; Photovoltaic cells; Plane waves; Solar cells; Time dependence; Titanium dioxide
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0244651

Electronic structure and near optical properties of anatase TiO2 doped with Ta is investigated using time-dependent density functional theory (TDDFT) and full-potential linearized augmented plane wave method (FLAPW). We calculated the dielectric functions of TiO2 and Ta-doped TiO2 both using independent particle (IP) approximations, which use time-independent Kohn-Sham orbitals and energies and using linear response formalism of TDDFT. The result shows several new peaks at low photon energy for both real and imaginary parts of dielectric functions of Ta-doped TiO2 compared to pure TiO2. The peaks obtained by IP results are associated with electronic transitions due to new electronic states near the Fermi level of single-particle band structure of Ta-doped TiO2. Meanwhile, the peaks obtained by TDDFT are more prominent and located in the low excitation energy range (below band gap energy). These peaks are associated with excitons and confirm a previous experiment study done for Ta-doped TiO2.