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SUMMARY:Photon Upconversion by Triplet Energy Migration in Molecular Assem
 blies - Professor Nobuhiro Yanai\, Kyushu University
DTSTART:20151005T133000Z
DTEND:20151005T143000Z
UID:TALK60884@talks.cam.ac.uk
CONTACT:Stuart Higgins
DESCRIPTION:We show exciting research opportunities when the concept of mo
 lecular self-assembly meets photon upconversion (UC) based on triplet-trip
 let annihilation (TTA). TTA-UC has attracted much attention for enhancing 
 solar energy harvesting devices such as photovoltaics and photocatalysis. 
 Previous examples of TTA-UC utilized the diffusion and collision of sensit
 izer and emitter molecules in solution or polymers\, however\, there are l
 imitations such as quenching by oxygen and low diffusion rate in the solve
 ntfree state. In this context\, we’re proposing a paradigm shift from th
 e molecular diffusion in dispersed systems to the energy migration in cond
 ensed systems (Figure 1). In dense dye assemblies\, triplet excitons can e
 ffectively migrate and annihilate. For the proof of concept\, we show the 
 first examples of TTA-UC in a solvent-free molecular liquid\, ionic liquid
 \, supramolecular assembly\, gel\, liquid crystal\, and metal-organic fram
 eworks (MOFs) (Figure 2). This approach allowed us to maximize UC quantum 
 yield even at extremely low excitation power density such as solar irradia
 nce.
LOCATION:Kapitza Building Seminar Room\, Cavendish Laboratory\, Department
  of Physics
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