jp412223m_si_001.pdf (332.61 kB)
Plasmon-Enhanced Triplet–Triplet Annihilation Using Silver Nanoplates
journal contribution
posted on 2014-03-27, 00:00 authored by Kianoosh Poorkazem, Amelia V. Hesketh, Timothy L. KellyPhoton
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.