Incoherent photon upconversion has attracted a lot of attention as it has the potential to surpass the Shockley−Queisser limit, thus generating substantial gains in overall solar conversion efficiency, up to 43% for crystalline silicon cells. Our recent work found that hybrid nanoparticle (NP)-organic triplet sensitization is another efficient and promising system that can be optimized through ligand chemistry. The transmitter in this process, which mediates triplet energy transfer from the NC sensitizer to an emitter in solution, plays a crucial role. In this work, by varying the linker length between carboxylic-acid-functionalized anthracene transmitters and NPs systematically, we discovered that Dexter transfer occurs at short distances, while a FRET mechanism dominates the long distance process. This leads to the highest reported up-conversion quantum yield of 14%. The presence of both mechanisms illustrate the different strategies for utilizing energy transfer in light-harvesting assemblies and the required considerations in device design to maximize energy transfer.

Distance-dependent energy transfer pathway between CdSe nanoparticles and anthracene during hybrid inorganic-organic upconversion

251st National Meeting (2016)

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