Marina Freitag

11% efficiency solid-state dye-sensitized solar cells with copper(II/I) hole transport materials

Solid-state dye-sensitized solar cells currently suffer from issues such as inadequate nanopore filling, low conductivity and crystallization of hole-transport materials infiltrated in the mesoscopic TiO2 scaffolds, leading to low performances. Here we report a record 11% stable solid-state dye-sensitized solar cell under standard air mass 1.5 global using a hole-transport material composed of a blend of [Cu (4,4′,6,6′-tetramethyl-2,2′-bipyridine)2](bis(trifluoromethylsulfonyl)imide)2 and [Cu (4,4′,6,6′-tetramethyl-2,2′-bipyridine)2](bis(trifluoromethylsulfonyl)imide). The amorphous Cu(II/I) conductors that conduct holes by rapid hopping infiltrated in a 6.5 μm-thick mesoscopic TiO2 scaffold are crucial for achieving such high efficiency. Using time-resolved laser photolysis, we determine the time constants for electron injection from the photoexcited sensitizers Y123 into the TiO2 and regeneration of the Y123 by Cu(I) to be 25 ps and 3.2 μs, respectively. Our work will foster the development of low-cost solid-state photovoltaic based on transition metal complexes as hole conductors.

Electrochemical Properties of Cu(II/I)-Based Redox Mediators for Dye-Sensitized Solar Cells

Three Cu(II/I)-phenanthroline and Cu(II/I)-bipyridine redox mediators are studied on various electrodes and in variety of electrolyte solutions using cyclic voltammetry and impedance spectroscopy o ...

The Researcher’s Guide to Solid-state Dye-sensitized Solar Cells

In order to sustainably support its ever-increasing energy demand, the human society will have to harvest renewable energy wherever and whenever possible. When converting light to electricity, silicon solar cells are the technology of choice to harvest direct sunlight due to their high performance and continuously dropping price. For diffused light and indoor applications, however, silicon is not the material of choice. To power the next gizmo in your smart home, dye-sensitized solar cells (DSCs) are a viable alternative. Made from inexpensive, earth-abundant, and non-toxic materials, DSCs perform best at low light intensity. So far, issues such as leakage of the liquid electrolyte and its corrosive nature have limited the commercialization of this technology. To overcome these limitations, solid-state DSCs (ssDSCs) – in which the liquid electrolyte is replaced by a solid material – have been developed. For many years their efficiencies have been poor, preventing them from being widely employed. In the past six years, however, research efforts have led them to rival with their liquid counterparts. Here, we will review recent advancements in the field of ssDSCs. Every device component will be acknowledged, from metal oxides and new dyes to novel hole transporters, dopants, counter-electrodes and device architectures. After reviewing materials, long-term stability of devices will be addressed, finally giving an insight into the future that awaits this exciting technology.