Comparative study of copper complexes with different anchoring groups by molecular modeling and its application to dye-sensitized solar cells

Copper complexes with different anchoring groups (based on biquinoline ligands with acetylacetone, catechol, hydroxamic acid, phosphonic acid and thiocarboxylic acid groups) have been studied by Density Functional Theory and Time-Dependent Density Functional Theory, also the integral equation formalism of the polarizable continuum model has been extended to the calculation of solvent effects. Maximum absorption wavelength reaches the highest value for the complex with hydroxamic acid as anchoring group but a low oscillator strength; the rest of the complexes fulfill both properties. In general, the molecular orbitals energy levels and the schematic representation of them suppose an appropriate electron transfer between the sensitizer and the semiconductor (TiO2), emphasizing more clearly for the copper complex with the thiocarboxylic acid. Chemical reactivity parameters like chemical hardness shows similitude for all molecular systems; but not so in the case of the electrophilicity index and electroaccepting power.

Graphical abstractCopper complexes with different anchoring groups (based on biquinoline ligands with acetylacetone, catechol, hydroxamic acid, phosphonic acid and thiocarboxylic acid groups) have been studied by Density Functional Theory and Time-Dependent Density Functional Theory, also the integral equation formalism of the polarizable continuum model has been extended to the calculation of solvent effects. Maximum absorption wavelength reaches the highest value for the complex with hydroxamic acid as anchoring group but a low oscillator strength; the rest of the complexes fulfill both properties. In general, the molecular orbitals energy levels and the schematic representation of them suppose an appropriate electron transfer between the sensitizer and the semiconductor (TiO2), emphasizing more clearly for the copper complex with the thiocarboxylic acid. Chemical reactivity parameters like chemical hardness shows similitude for all molecular systems; but not so in the case of the electrophilicity index and electroaccepting power.Figure optionsDownload full-size imageDownload as PowerPoint slide