Molecular Modelling
Molecular modelling constitutes a transversal research line within the group, supporting activities from nonlinear optics (NLO) to more recent developments in dye-sensitized solar cells (DSSC) and photoactive systems. Over the last 15 years, this line has provided a theoretical framework to understand and predict the behaviour of π-conjugated molecules, establishing direct links between molecular structure and functional properties.
Initially, this work focused on NLO-active push–pull D–π–A systems, with particular emphasis on intramolecular charge transfer and the use of descriptors such as bond length alternation (BLA) to rationalize nonlinear optical response. Computational studies were applied to different families of chromophores, including systems with thiophene and thiazole spacers, merocyanine-type structures and highly polarized zwitterionic compounds. Special attention was devoted to proaromatic systems such as 4H-pyranylidene, allowing the study of the interplay between aromatic and quinoidal contributions and their impact on molecular polarization and hyperpolarizability. In this context, simple physical models, such as the two-level approximation, have been used to relate structural parameters like BLA with the nonlinear optical response.
These studies, based on density functional theory (DFT) and time-dependent DFT (TD-DFT), enabled the evaluation of molecular dipole moments, frontier molecular orbitals, charge-transfer transitions and first hyperpolarizabilities. In addition, the study of electronic density distribution and excited states provided a consistent interpretation of experimental measurements, supporting the establishment of robust structure–property relationships.
More recently, the scope has been extended to DSSC and other photoactive systems, where modelling has been used to investigate the electronic structure of dyes, their absorption properties and their interaction with semiconductor surfaces. In particular, calculations have addressed energy level alignment, charge injection processes and the influence of anchoring groups and π-spacers on device performance, as well as the estimation of electrochemical properties such as oxidation potentials (Eox) and optical absorption characteristics.
Depending on the system, calculations are performed both in the gas phase and including solvent effects through continuum models, providing a more realistic description of experimental conditions.
All calculations are carried out using computational resources available within the research group, ensuring flexibility and continuity in the theoretical support across different research lines. Overall, molecular modelling acts as a unifying tool, bridging theory and experiment and enabling the rational design of advanced electro- and photoactive materials.
and promising extension of the line.
Selected publications
Researchers involved in this line:
Jesús Orduna
Ideas for figures / images (to include later)