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The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes
Published on: April 10, 2015
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Adapting Ruthenium Sensitizers to Cobalt Electrolyte Systems
Sangeeta Amit Kumar1,2, Maxence Urbani3,4, María Medel3
1†Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology (EPFL), Station 6, CH 1015 - Lausanne, Switzerland.
The Journal of Physical Chemistry Letters
|August 16, 2015
Summary
Bulky substitutions in a new ruthenium(II) bipyridine complex (TT-230) enhance dye-sensitized solar cell performance. This strategy prevents electron recombination, significantly increasing the open-circuit potential for improved solar energy conversion.
Area of Science:
- Materials Science
- Photovoltaics
- Coordination Chemistry
Background:
- Cobalt-based electrolytes offer higher open-circuit potential (VOC) in dye-sensitized solar cells (DSCs) compared to traditional iodide/tri-iodide mediators.
- While cobalt complexes achieved >1 V VOC with porphyrin sensitizers, conventional ruthenium(II)-polypyridyl complexes like C101 struggle due to increased recombination.
- Enhanced recombination in conventional DSCs limits the achievable open-circuit potential, hindering performance.
Purpose of the Study:
- To investigate the impact of bulky substituents on heteroleptic ruthenium(II) bipyridine complexes for DSC applications.
- To enhance the open-circuit potential (VOC) of dye-sensitized solar cells by mitigating recombination.
- To develop novel ruthenium(II) complexes for efficient solar energy conversion.
Main Methods:
- Synthesis and characterization of a new heteroleptic ruthenium(II) bipyridine complex (TT-230) featuring bulky cyclopenta(2,1-b;3,4-bA)dithiophene moieties.
- Fabrication and testing of dye-sensitized solar cells using the TT-230 complex and cobalt-based electrolytes.
- Investigation of recombination dynamics using transient photovoltage decay measurements.
Main Results:
- The TT-230 complex, with bulky substituents, achieved a high open-circuit potential in dye-sensitized solar cells.
- Bulky groups on the ruthenium complex effectively suppressed back-electron transfer (recombination).
- Transient photovoltage decay confirmed reduced recombination rates in devices utilizing the TT-230 complex.
Conclusions:
- The strategic incorporation of bulky substituents in ruthenium(II) bipyridine complexes is a viable strategy to increase open-circuit potential in dye-sensitized solar cells.
- Suppression of recombination through steric hindrance is key to achieving higher VOCs, surpassing limitations of conventional complexes.
- This research offers a pathway towards more efficient and stable dye-sensitized solar cells using tailored ruthenium complexes and cobalt electrolytes.
