| dc.description.abstract | Due to its wide band gap and high electron mobility, ZnO is a promising semiconductor material for
dye-sensitized solar cells (DSSCs). This research utilizes ab initio density functional theory (DFT) as implemented in the
Quantum ESPRESSO software. Both standard DFT and DFT+U formalism were employed to explore the structural, elastic,
electronic and optical characteristics of wurtzite ZnO (W-ZnO). The optimal lattice constants a = b =3.289 Å and c =
5.29032 Å were obtained in DFT calculations while in the DFT+U techniques, a=b=3.269 Å and 5.211 Å were achieved. This
was found to align with prior findings in the literature but exhibiting a minor reduction during the DFT+U calculations. It was
noted that W-ZnO exhibits a direct band gap at the gamma point. The calculated band gaps were determined to be 0.79 eV,
1.45 eV, and 3.19 eV for the standard DFT, DFT + Ud, and DFT + Ud + Up calculations, respectively. From the density of state
(DOS) analysis, the valence band was noted to be predominantly influenced by the O-2s, Zn-3d, and O-2p orbitals, while the
conduction band was primarily governed by the O-2p and Zn-4s orbitals. The computed elastic constants, along with the bulk
and shear moduli of W-ZnO conformed with stability criterion of hexagonal structures indicating that W-ZnO is
mechanically stable in its ground state. Overall, W-ZnO demonstrated low absorption capacity and high transmittance within
the visible spectrum, rendering it a promising candidate for applications in dye-sensitized solar cells (DSSCs). | en_US |
