Photons and Electrons on the Move

Introduction

The conversion of sunlight photons to electrons is the essence of the natural photosynthesis that powers life. Dedicated antennas funnel the sun's energy towards reaction centres. Amazingly, nature reaches almost perfect photon-to-electron conversion efficiency, while it regulates down at high light levels for protection and survival.

Research Questions

How does nature dynamically reorganize the membrane architecture, its packing, order, and diffusion under light stress?

• Which pathways are taken to charge separation?
• What is the role of fluctuations, coherences, color, and vibrations?

Recent Achievements

My group recently succeeded in the first detection of the fs spectral progression of a single exciton, the nanoscale tracking of electron transport, and revealed energy disorder of a single photosynthetic complex. These pioneering results, together with our expertise in fs pulse control and nanoimaging, set the grounds to now address photosynthetic light-to-charge transfer in real nanospace and ultrafast.

Specific Objectives

1. Energy transport on the nanoscale: Tracking spatiotemporal membrane transport by super-resolved transient optical microscopy and nanophotonic light localization to reveal disorder and quantify diffusion.

2. Light to charge: Photo-current detection of the energy flow. By ultrafast photo-thermoelectric graphene and photo-electrochemical detection, I will probe charge separation of the reaction center directly and quantify rate and efficiency.

3. Multidimensional spectra on the nanoscale: By collinear 2D spectroscopic imaging with photocurrent and fluorescence detection, I will map the development of the energy landscape at special membrane spots, ultimately on a single complex.

4. Functional imaging: Visualize the dynamic light response of the membrane architecture, the changes in packing density, (dis)order, diffusion, and pathways to charge separation.

Relevance

The novel toolset of FastTrack and the insights on nature's energy strategies are directly relevant for artificial photosynthesis and solar technology.