Plasmon-Enhanced Triplet–Triplet Annihilation Using Silver Nanoplates
journal contributionposted on 27.03.2014 by Kianoosh Poorkazem, Amelia V. Hesketh, Timothy L. Kelly
Any type of content formally published in an academic journal, usually following a peer-review process.
Photon upconversion processes have attracted substantial interest as a means of circumventing the Shockley–Queisser limit for single-junction photovoltaic devices. Despite this promise, the quantum yield of most upconversion processes is very low at the light intensities typical of solar radiation (∼100 mW/cm2). Additionally, bimolecular upconversion processes that rely on molecular diffusion (e.g., triplet–triplet annihilation) typically see further reductions in quantum yield when the upconverting chromophores are confined to a solid state or thin film matrix. Here we report a plasmon-based enhancement of the triplet–triplet annihilation process when silver nanoplates are embedded in poly(methyl methacrylate) thin films containing the upconverting materials palladium(II) octaethylporphyrin and 9,10-diphenylanthracene. The silver nanoplates are synthesized with localized surface plasmon resonance bands tailored to overlap strongly with the Q-band of the porphyrin, leading to enhanced light absorption within the film and higher overall triplet concentrations. Optimization of the silver nanoplate loading leads to a nearly 10-fold increase in the upconverted light intensity compared with control samples containing no silver.