title: Experimental demonstration of photon upconversion via cooperative energy pooling.
abstract: Photon upconversion is a fundamental interaction of light and matter that has applications in fields ranging from bioimaging to microfabrication. However, all photon upconversion methods demonstrated thus far involve challenging aspects, including requirements of high excitation intensities, degradation in ambient air, requirements of exotic materials or phases, or involvement of inherent energy loss processes. Here we experimentally demonstrate a mechanism of photon upconversion in a thin film, binary mixture of organic chromophores that provides a pathway to overcoming the aforementioned disadvantages. This singlet-based process, called Cooperative Energy Pooling (CEP), utilizes a sensitizer-acceptor design in which multiple photoexcited sensitizers resonantly and simultaneously transfer their energies to a higher-energy state on a single acceptor. Data from this proof-of-concept implementation is fit by a proposed model of the CEP process. Design guidelines are presented to facilitate further research and development of more optimized CEP systems.
authors.affiliation: Department of Physics, University of Colorado Boulder, Boulder, Colorado 80309, USA.
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Weingarten
authors.affiliation: Department of Physics, Colorado School of Mines, Golden, Colorado 80401, USA.
authors.forename: Michael D
authors.initials: MD
authors.lastname: LaCount
authors.affiliation: Department of Physics, University of Colorado Boulder, Boulder, Colorado 80309, USA.|Chemistry and Nanoscience Center, National Renewable Energy Laboratory, Golden, Colorado 80401, USA.
authors.forename: Jao
authors.identifier: 0000-0001-5851-6163
authors.initials: J
authors.lastname: van de Lagemaat
authors.affiliation: Chemistry and Nanoscience Center, National Renewable Energy Laboratory, Golden, Colorado 80401, USA.|Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, Colorado 80309, USA.|Chemistry and Nanoscience Center, Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, Colorado 80309, USA.
authors.forename: Garry
authors.initials: G
authors.lastname: Rumbles
authors.affiliation: Department of Physics, Colorado School of Mines, Golden, Colorado 80401, USA.
authors.forename: Mark T
authors.initials: MT
authors.lastname: Lusk
authors.affiliation: Department of Physics, University of Colorado Boulder, Boulder, Colorado 80309, USA.|Chemistry and Nanoscience Center, Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, Colorado 80309, USA.|Department of Electrical, Computer, and Energy Engineering, University of Colorado Boulder, Boulder, Colorado 80309, USA.
authors.forename: Sean E
authors.initials: SE
authors.lastname: Shaheen