TITLE:
Theoretical Design of Complex Molecule via Combination of Natural Lawsone and Synthetic Indoline D131 Dyes for Dye Sensitized Solar Cells Application
AUTHORS:
Nyanda Madili, Alexander Pogrebnoi, Tatiana Pogrebnaya
KEYWORDS:
DSSCs, Lawsone, Indoline D131, Molecular Design, IR Spectra, UV-Vis Spectra, DFT, TD-DFT
JOURNAL NAME:
Computational Chemistry,
Vol.6 No.4,
October
31,
2018
ABSTRACT:
The dye sensitized solar cells (DSSCs) have been extensively studied due to
their low production cost and simple fabrication process. Dye co-sensitization
broadens the absorption spectrum of the sensitizer; thus enhances light harvesting
efficiency; and contributes to the improvement of the DSSCs overall
efficiency. In this study we performed theoretical design of complex molecule
(C45H32N2O4) through combination (esterification reaction) of the natural dye
lawsone and synthetic metal free indoline dye D131. The excitation energies,
vibration spectra, molecular structures, electronic absorption spectra and
electron transitions in individual dyes and complex molecule were investigated
using density functional theory (DFT) and time dependent density
functional theory (TD-DFT) B3LYP5 methods, with 3-21G, 6-31G and
6-31G(d,p) basis sets. The UV-Vis absorption spectra of the individual dyes
and their mixture in chloroform solution were measured using spectrophotometer.
For the complex formation reaction, enthalpy, entropy and Gibbs
free energy were calculated and the results indicated the reaction was endothermic
and non-spontaneous. Electron density distribution of the frontier
and adjacent molecular orbitals and energy levels alignment were used for
analysis of the electronic spectra and mechanism of transitions. The results
indicated that the designed complex molecule satisfied the requirements for
good photosensitizer of DSSCs.