CONTRIBUTION TO OUR SCHOOL

Is dye-sensitized solar cells a dying field?

Further strengthen by the recent achievement of 14 % power conversion efficiency by combining a cobalt (+III/+II) redox mediator with two organic sensitizers,¹ the credibility of dye-sensitized solar cells (DSC) as a silicon alternative has never been as unequivocal as today. Nevertheless, progress in OPV and DSC became completely outshined by a "new" solar cell technology based on halide perovskite for which the conversion performances reached crossed 20 % in a period of only four years development, getting together OPV and DSC main key players devoted to this research field and consequently bringing a shadow onto these two former technologies.

For very long time, DSC field mainly concentrated on development of new dyes to extend light capture towards red and on the mesostructuration of the anatase TiO₂ to enhance the charge collection efficiency, with final aim to reach a new record efficiency. In this panorama, much less attention has been paid on electrolyte to extend the device stability against IEC61646 standard ageing protocol. For practical application of photovoltaics, the main challenge to decipher is how to make it efficient, stable and at a competitive price to fossil fuel burning?... while, of course, using materials and processes compatible with the respective environmental regulations.

In this panorama, much less attention has been paid on electrolytes to extend the device stability against IEC61646 standard ageing protocol and even much less towards understanding the chemical interactions and electrochemical degradation mechanisms in the device leading to the performance fading. In these two lectures, against the preconceived idea that the most stable DSC constituent is TiO₂, we will show how TiO₂ is crucial to obtain highly efficient devices by promoting charge transport vs. recombination and how crucial is TiO₂ for the stability aspect. A second part will be dedicated to new dyes and redox mediator developments towards a new branch of fully transparent and colourless dye-solar cells.

Is dye-sensitized solar cells a dying field ? Let’s discuss it at ISOPHOS-MAPHEBIO !

References
1) K. Kakiage, Y. Aoyama, T. Yano, K. Oya, J. Fujisawa, M. Hanaya, Chem. Commun., 2015, 51, 15894-15897.
2) M. Flasque, A. Nguyen Van Nhien, J. Swiatowska, A. Seyeux, C. Davoisne, F. Sauvage, ChemPhysChem 2014, 15(6), 1126-1137.