Polaronic charge transport in novel solid-state photocatalysts for solar-fuel production
|Feb 2015 – present||
DFG-Project ME 4387/1-1
Scientific director: C. Merschjann (presently @ Helmholtz-Zentrum Berlin)
In this ongoing project, we investigate the charge-transport properties of novel solid functional materials, most prominently different polymeric carbon nitrides (PCN), but also oxides and oxynitrides (e.g., TaON). These materials are synthesized and tested for application in photocatalysis, especially solar water splitting, to generate so-called “solar fuels”.
The aim is to shed light on the complete lifecycle of photoexcited carriers, from sub-100-fs towards milliseconds, and thus to get information about their concentration and mobility, as well as trapping and recombination scenarios. This will help to identify possible bottlenecks in the utilization of photogenerated charges for heterogeneous catalysis.
We use mainly transient optical spectroscopy, namely transient absorption (TA) and photoluminescence (TRPL) as complementary techniques, showing us the “life and death” of photoexcitations. Thus, we found evidence for an actual low-dimensional charge transport in PCN, confined to channels vertical to the graphitic planes of the van-der-Waals-bound material.
A new setup for TA in powdery materials was designed and tested, and is currently producing data.
Read more here…