Structured Excitation Energy Transfer: Tracking Exciton Diffusion below Sunlight Intensity.
ACS Photonics
; 11(3): 1318-1326, 2024 Mar 20.
Article
en En
| MEDLINE
| ID: mdl-38523751
ABSTRACT
With the increasing demand for new materials for light-harvesting applications, spatiotemporal microscopy techniques are receiving increasing attention as they allow direct observation of the nanoscale diffusion of excitons. However, the use of pulsed and tightly focused laser beams generates light intensities far above those expected under sunlight illumination, leading to photodamage and nonlinear effects that seriously limit the accuracy and applicability of these techniques, especially in biological or atomically thin materials. In this work, we present a novel spatiotemporal microscopy technique that exploits structured excitation in order to dramatically decrease the excitation intensity, up to 10,000-fold when compared with previously reported spatiotemporal photoluminescence microscopy experiments. We tested our method in two different systems, reporting the first exciton diffusion measurement at illumination conditions below sunlight, both considering average power and peak exciton densities in an organic photovoltaic sample (Y6), where we tracked the excitons for up to five recombination lifetimes. Next, nanometer-scale energy transport was directly observed for the first time in both space and time in a printed monolayer of the light-harvesting complex 2 from purple bacteria.
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Bases de datos:
MEDLINE
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En
Revista:
ACS Photonics
Año:
2024
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Article
País de afiliación:
España