Optical Sciences

Biomolecules and nanostructures

The Optical Sciences group studies the interaction of light and matter. Our current focus is on detection and sensing/imaging with an emphasis on the development of integrated photonics. We are part of Twente University's Department of Science and Technology and member of the MESA+ institute.


Impact of the Anchoring Ligand on Electron Injection and Recombination Dynamics at the Interface of Novel Asymmetric Push-Pull Zinc Phthalocyanines and TiO2

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Divya Sharma, Gerwin Steen, Jeroen P. Korterik, Miguel García-Iglesias, Purificacion Vázquez, Tomás Torres, Jennifer L. Herek, and Annemarie Huijser
Journal of Physical Chemistry C
vol. 117 issue 48 p. 25397-25404 November 12, 2013

Phthalocyanines are promising photosensitizers for dye-sensitized solar cells (DSSCs).
A parameter that has been problematic for a long time involves electron injection (EI) into the TiO2.
The development of push-pull phthalocyanines shows great potential to improve the ratio of EI to back electron transfer (BET). We have studied the impact of the anchoring ligand on EI and BET using transient absorption. The best performing derivative, which has a dicarboxylic acid anchoring ligand (TT15, DSSC efficiency of 3.96%), shows the fastest EI. The EI process occurs via an ultrafast component (~700 fs for all derivatives) and a slower component (5.8 ps for TT15). The ps component is considerably slower for the other derivatives studied. Also BET depends on the anchoring ligand and is the slowest for TT15. This knowledge is essential for the optimization of the EI/BET ratio and the efficiency of a phthalocyanine-based DSSC.
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