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Transient absorption spectroscopy of polymer/carbon nanotube hybrids

timlohk - Posted on 01 October 2014

Project Description: 

Polymers which can absorb visible light are synthesized by coupling or reversible-addition fragmentation chain transfer polymerization to functionalize carbon nanotubes (CNTs). The photoinduced electron transfer from the polymer to the CNT is investigated by transient absorption (TA) spectroscopy. Density functional theory is used to elucidate the electronic transitions of the polymers and explain the TA results.

Researcher name: 
Chan, Wai Kin
Researcher position: 
Professor
Researcher department: 
Department of Chemistry
Researcher email: 
waichan@hku.hk
Researcher name: 
Phillips, David Lee
Researcher position: 
Chair Professor
Researcher department: 
Department of Chemistry
Researcher email: 
phillips@hku.hk
Research Project Details
Project Duration: 
04/2013 to 12/2018
Project Significance: 
The new materials have the potential to miniaturize light detectors and sensors. The TA results can be used to deduce the mechanism and the efficiency of the photoinduced electron transfer in the polymer/CNT hybrids and propose design rationale of the hybrids to improve their optoelectronic properties.
Results Achieved: 
A polymer incorporated with pyrenylcarbazole pendant groups was successfully synthesized to functionalize multi-walled CNTs (MWCNTs). Investigated by TA spectroscopy, the electron transfer from the MWCNT to the polymer is very efficient and in the scale of femtosecond. The electronic transitions of the pyrenylcarbazole moiety were calculated by density functional theory. The results have been published in New J. Chem., 2013, 37, 1833-1842. Photo-sensitizing block copolymers have been synthesized to prepare the block copolymer/MWCNT hybrid. MD simulations have been performed to explain the photophysical properties. A paper is being prepared for this work.
Remarks: 
The electronic transitions and geometric optimizations were performed by density functional theory in Gaussian09.