L–Alanine adsorbed aluminum doped ZnO structures for nanocomposites with tailored photovoltaic properties: a DFT study

Abstract

The l-Alanine adsorbed Al-doped Zn8O8 (l-A-AlZn7O8) with an amine site (P1) and carboxyl site (P2) were investigated through density functional theory (DFT) calculations using B3LYP method with 6-31G (d,p) and LanL2DZ basis sets to improve the electrochemical properties. The geometrical parameters, optical properties, lowest harmonic frequency, polarizability, dipole moment, Mulliken atomic charges, adsorption energy, HOMO–LUMO gap, molecular electrostatic potential, global reactivity descriptors, Fukui functions and density of states (DOS) were examined in detail. The adsorption energies have been calculated for different possible configurations of the l-A-Al(ZnO)n. The excited state geometry optimization and UV–Vis spectral analysis were carried out with the time-dependent DFT. The net charge transfer and local charges of l-A-AlZn7O8 are studied by natural bond orbital analysis. The DOS plot reveals that the remarkable orbital hybridization and strong interaction between l-Alanine and Al-doped ZnO. The electronic properties of l-A-AlZn7O8 undertake an important modification that indicates the noteworthy changes in its electrical conductivity. The P1 site characteristics were interesting for dye-sensitized solar cells as it offers significant adsorption energy, elevated net charge transferring values, and smaller bond distances in the P1 site of l-A-AlZn7O8.