Ultrafast Action Spectroscopy of Hybrid States for Soft Optoelectronic Materials Engineering

A central challenge in the development of modern optoelectronic materials is the ability to characterise and control their electronic and structural dynamics with high time resolution and spatial selectivity. This is increasingly important for solution processable 'soft' nanomaterials where the electronic and structural dynamics are highly entangled and time dependent. This entanglement leads to the hybridisation of different electronic and vibrational levels and the emergence of new states that ultimately determine the materials' optoelectronic properties and play the key role in a range of processes from charge photogeneration and exciton fission to the localisation and multiplication of electronic states. A technology capable of characterising hybrid states operando would be indispensable for material engineering and device development.

In the last 8 years, my team has exposed the role of hybridisation between electronic and vibrational states in a range of soft electronic nanomaterials. We have also developed a new set of methods for the ultrafast spectroscopy of nanodevices at working conditions. This brings us in a unique position to combine this expertise with recent developments in coherent multidimensional spectroscopies and versatile nanoprobe platforms, to develop a novel toolkit for time-resolved operando mapping of charge dynamics in optoelectronic materials, including the evolution hybrid states and their molecular origins. This will open new possibilities in engineering material properties by the targeted adjustments of the densities of electronic and vibrational states, interstate couplings and structural dynamics. These findings will bring a new mechanistic understanding of electronic processes in soft molecular materials and can have direct consequences for the practical applications, including the development of photovoltaics with high open-circuit voltage, emissive printable materials, or efficient and robust solar fuel devices.