Controlling Supramolecular Structures to Tailor Optoelectronic Properties for Photoenergy Conversion

Supramolecular structures play a key role in determining the photonic and electronic properties of materials. To achieve precise control over these structures, we exploit the interfacial arrangement of amphiphilic dyes by Langmuir-Blodgett (LB) and related techniques. This approach allows the formation of well-defined layers and stacks with tunable optoelectronic properties, which are critical for efficient photoenergy conversion.

In our study, we demonstrate how the morphology of these supramolecular structures influences the electronic energy levels, resulting in a morphological variation of 120 meV in LUMO energies within fullerene thin films. Using amphiphilic molecules as a model system, we systematically tuned the nearest neighbor interactions by adjusting the surface pressure during deposition and varying the number of Langmuir monolayers deposited.

To further improve the precision of the deposition process, we developed a novel continuous rolling Langmuir layer transfer technique. This method minimizes the flow of Langmuir layers during deposition and allows fine-tuning of LUMO energies by 70 meV as determined by square wave voltammetry. The resulting well-defined morphologies allowed us to develop morphological descriptors that describe and predict the average LUMO energies of the film stacks.

Our results highlight the significant influence of controlled supramolecular structuring on the optoelectronic properties of materials and provide valuable insights for the design of advanced photoenergy conversion systems.