Solar cell devices for solar energy conversion suffer from poor efficiencies partly due to their inability to absorb photons below their bandgap. Triplet-triplet annihilation upconversion (TTA-UC) is an attractive technique whereby two low energy photons can be converted to one photon with higher energy at relatively low light intensities.<br/>Solid-state UC systems are highly desirable for real world device applications and a lot of effort has been invested into the development of solid-state UC. However, the solid-state UC efficiency is low due to the limited triplet diffusion, aggregation and phase separation of chromophores at high concentration in solid polymeric matrices. To optimize triplet diffusion, a series of new molecules with multiple 9,10-diphenylanthracence (DPA) subunits were synthesized where the TTA process can occur intramolecularly. A better understanding between the UC efficiency and molecular geometries was obtained by using these new emitters, some structures are shown in <b>Figure 1</b>. Nanoparticles, with the advantage of controlling the microscopic arrangement, have also been proposed as another strategy to overcome the component aggregation and separation problems.<br/>By using the platinum octaethylporphyrin (PtOEP) as the sensitizer, the new emitters show efficient TTET and TTA-UC both in solid polymeric matrix and nanoparticles. Therefore, efficient air stable solid-state TTA-UC can be achieved by using these new anthracene derivatives.

New anthracene derivatives towards air stable solid-state triplet-triplet annihilation upconversion

256th National Meeting (2018)

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