Efficient Electron Transfer and Sensitizer Regeneration in Stable π-Extended Tetrathiafulvalene-Sensitized Solar Cells
作者:Sophie Wenger、Pierre-Antoine Bouit、Qianli Chen、Joël Teuscher、Davide Di Censo、Robin Humphry-Baker、Jaques-E. Moser、Juan Luis Delgado、Nazario Martín、Shaik M. Zakeeruddin、Michael Grätzel
DOI:10.1021/ja909291h
日期:2010.4.14
The development of metal-free organic sensitizers is a key issue in dye-sensitized solar cell research. We report successful photovoltaic conversion with a new class of stable tetrathiafulvalene derivatives, showing surprising electrochemical and kinetic properties. With time-resolved spectroscopy we could observe highly efficient regeneration of the photo-oxidized tetrathiafulvalene sensitizers, which were attached to a mesoporous TiO2 film, by a redox mediator in the pores (iodide/tri-iodide), even though the measured driving force for regeneration was only similar to 150 mV. This important proof-of-concept shows that sensitizers with a small driving force, i.e. the oxidation potential of the sensitizer is separated from the redox potenial of the mediator by as little as 150 mV, can operate functionally in dye-sensitized solar cells and eventually aid to reduce photovoltage losses due to poor energetic alignment of the materials.