Photon upconversion through triplet-triplet annihilation (TTA UC) has emerged as a promising technology for solar energy conversion, as this technology converts long wavelength optical radiation into higher energy photons. Expansion of the sensitizer spectral coverage into the NIR region offers a means to harvest energy that is typically lost in conventional silicon-based photovoltaics. In this regard, supermolecular chromophores composed of (porphinato)zinc(II) (PZn) and metal(II)polypyridyl (M) units bridged via ethyne connectivity (M-PZn-M chromophores) stand as promising sensitizer candidates for long wavelength TTA UC as such M-PZn-M supermolecules possess broad, high oscillator strength NIR absorption manifolds, feature fast (ps) intersystem cross rate constants, and possess low-lying, highly polarized triplet excited states having long (�s) lifetimes. We describe multiple examples of these chromophores that possess appropriate excited-state energy levels for exothermic triplet-triplet energy transfer to acceptor/annihilators that provide NIR-to-visible photon upconversion characterized by anti-Stokes shifts that approach 1 eV. We demonstrate further that the combination of these supermolecular sensitizers with rubrene as a triplet acceptor/annihilator enables NIR-to-vis TTA UC under low power noncoherent illumination.

Near-infrared-to-visible photon upconversion by highly conjugated sensitizers under low-power noncoherent illumination

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.