Hi group,
Today we have Tony Wu, a postdoc candidate giving a talk at 3 pm, Division
room. The talk is has a mix of quantum chemistry, excitonics and materials
discovery, hope you can come!
His talk title is:
*Towards High Efficiency Solar Cell Utilizing Singlet Fission and
Triplet-Triplet Annihilation*
Abstract:
Single bandgap solar cell, such as the conventional silicon solar cell, are
bounded by an upper limit of 32% power conversion efficiency (PCE) due to
Shockley-Queisser limit. Most of the energy losses comes from non-absorbed
lower energy photons and themalization decay loss of higher energy photons.
To overcome the Shockley-Queisser PCE limit, down conversion and up
conversion mechanisms are some possible methods. We explored the
possibility of utilizing singlet fission and triplet-triplet annihilation
phenomenon in some organics for energy down conversion and up conversion.
We found that internal quantum efficiency for exciton generation reaches
127% for tetracene [1]. For up conversion, the efficiency is about 0.28%
[2]. Finally, we would show current progresses toward utilizing singlet
fission in silicon solar cell.
[1] T. Wu, et al. "Singlet fission efficiency in tetracene-based organic
solar cells", APL 2014.
[2] T. Wu, et al. "Solid state photon upconversion utilizing thermally
activated delayed fluorescence molecules as triplet sensitizer", APL 2015.
Ben
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