Watching Excitons in Photoactive Organic Frameworks

Introduction

One of the most urgent challenges our society is facing nowadays is the development of an energy economy based on renewable resources. A fascinating approach is artificial photosynthesis, where solar energy is exploited to produce chemical fuels out of carbon dioxide, water, and sunlight.

Technological Advances and Challenges

While recent technological advances are bringing us closer to the goal of developing efficient light-harvesting platforms, a fundamental gap about the atomic-scale mechanisms remains to be filled. Understanding the atomistic details of the processes involved is of tremendous importance to drive a rational design of photoactive materials.

Key Questions

Relevant questions include:

• How do electrical charges move upon light absorption?
• How does the atomic structure influence the ability to harvest light?
• Why do some materials work better than others?

Answering questions such as these represents an extraordinarily demanding task, since excitons, the most fundamental light-induced excitations, composed of bound electron-hole pairs, are only transient short-lived entities occurring in complex materials.

Project Goals

The WEPOF project aims at enabling the direct experimental observation of excitons in photoactive covalent organic frameworks, providing a fundamental understanding of photoexcited states in energy materials.

Methodology

While the structural complexity of organic frameworks will be tackled by individuating elementary functional units, allowing rationalizing their structure-function relations, the development of unique scanning probe microscopy methods will enable us to watch excitons on their relevant length- and timescales.

Conclusion

The understanding of excitonic processes will allow steering the design of photoactive materials with improved energy conversion efficiency, providing a conceptual framework for next-generation material platforms for artificial photosynthesis.