Photon upconversion, the process wherein light of long wavelength is frequency converted
to photons of higher energy, is readily achieved at low incident power through sensitized
triplet–triplet annihilation (TTA) in various chromophore combinations spanning the UV to
the near-IR. This emerging wavelength-shifting technology truly represents a viable route
towards converting low energy terrestrial solar photons into light adequate to drive electron
transfer in operational photovoltaics. Generalized molecular design constraints, all …

Upconversion (UC), a process that can convert two or more photons with low energy to a
single photon of higher energy, has the potential for overcoming the thermodynamic
efficiency limits of sunlight-powered devices and processes, including photovoltaic cells,
photocatalytic reactions, and photoelectrosynthetic processes. The UC phenomenon is
traditionally synonymous with second-harmonic generation using nonlinear inorganic
crystals and the sequential excitation of inorganic host materials doped with rare-earth …