Abstract
The nature of the highly efficient energy transfer in photosynthetic light-harvesting
complexes is a subject of intense research. Unfortunately, the low fluorescence efficiency and limited photostability hampers the study of individual light-harvesting complexes at ambient conditions. Here we demonstrate an over 500-fold fluorescence enhancement of lightharvesting complex 2 (LH2) at the single-molecule level by coupling to a gold nanoantenna.
The resonant antenna produces an excitation enhancement of circa 100 times and a
fluorescence lifetime shortening to B20 ps. The radiative rate enhancement results in a 5.5-fold-improved fluorescence quantum efficiency. Exploiting the unique brightness, we have recorded the first photon antibunching of a single light-harvesting complex under ambient conditions, showing that the 27 bacteriochlorophylls coordinated by LH2 act as a nonclassical single-photon emitter. The presented bright antenna-enhanced LH2 emission is a highly promising system to study energy transfer and the role of quantum coherence at the level of single complexes.
| Original language | English |
|---|---|
| Article number | 4236 |
| Number of pages | 7 |
| Journal | Nature Communications |
| Volume | 5 |
| DOIs | |
| Publication status | Published - 2014 |
| Externally published | Yes |
Keywords
- pigment-protein complexes
- purple bacterial lh2
- exciton delocalization
- molecule fluorescence
- energy-transfer
- optical antennas
- nanoantennas
- dynamics
- spectroscopy
- dna