Photosensitizers for photocatalytic water splitting

I suppose that you have noticed the hype around new energy sources during last decades even if you are not working in this field. As a continuation of the Light2Hydrogen project, we have also addressed the properties of quite popular iridium-based photosensitizers – molecules which absorb light and transfer energy or electrons further to catalysts. The idea behind this project is to use sunlight to split water into hydrogen and oxygen. The former can be then used as an ecologically clean fuel since upon combustion it produces only water.


In collaboration with the group of Stefan Lochbrunner, we have studied the influence of chemical derivation onto the absorption spectra as well as the nature of the most important electronic states.  The “bright” absorbing states are important to acquire as much solar energy as possible. For this purpose, it is of interest to shift them to lower energies to increase the overlap with the sun spectrum. In turn, the character of the lowest “dark” state is essential for the efficiency of further reactions, for instance, electron transfer to water reduction agents. We have looked at a series of organic ligands bound to iridium ions and formulated recommendations which can help for the rational design of the photocatalysts.

The article is published in a themed issue under the editorship of Matthias Bauer:

O.S. Bokareva, T. Möhle, A. Neubauer, S.I. Bokarev, S. Lochbrunner, O. Kühn Chemical Tuning and Absorption Properties of Iridium Photosensitizers for Photocatalytic  Applications Inorganics 2017, 5(2), 23.