Mathias Micheel | Researcher

Hello there! I’m Dr. Mathias Micheel, a postdoctoral scientist currently employed at the Leibniz-Institute of Photonic Technology in Jena, Germany. On this website, you may find more about my research and myself. From time to time, I might even drop random thoughts here - just like it was my personal blog in 2004!

And if in a distant future the supply of coal becomes completely exhausted, civilization will not be checked by that, for life and civilization will continue as long as the sun shines! – Giacomo Ciamician (1912). The photochemistry of the future. Science, 36(926), 385-394. doi: 10.1126/science.36.926.385

More than 100 years ago, Ciamician expressed his vision of a civilization which covers its energy needs not on the basis of coal (which he called fossil solar energy), but by direct utilization of solar energy. Instead of smokestacks from coal and oil factories, the chemical industry of the future will use glass tubes to drive their reactions. As a child from the Ruhr area, with its long history in coal mining and steel refining, I am every much committed to realizing his dream, which remains unfulfilled to date, and try to convert solar energy into so-called solar fuels.

At the moment, my research interest revolves around colloidal semiconductor nanoparticles, which can absorb visible sun light, their light-induced interaction with redoxactive molecules and polymers. In particular, I consider myself an expert in the spectroscopic characterization by means of time-resolved and steady state absorption and photoluminescence spectroscopies to investigate charge separation, localization and recombination processes in these structures in timescales from hundreds of femtoseconds to dozens of nanoseconds.

news

Sep 12, 2022	Our review “Assembly, Properties, and Application of Ordered Group II–VI and IV–VI Colloidal Semiconductor Nanoparticle Films” has been published in Advanced Materials Interfaces! We’re also thrilled to contribute the Inner Back Cover picture for the October edition!
Sep 9, 2022	I have been elected yPC chairperson!
Jun 26, 2022	New preprint on ChemRxiv! We directly functionalized thin CdSe quantum dot films with mlecular hydrogenase mimics and provided in-depth characterization of the functionalization and catalytic activity. Great collaboration between Leibniz-IPHT, Uni Jena, and Uni Ulm!
Feb 5, 2022	My rebuttal to the Krylov et al. article about Cancel Culture in Chemistry has been published on the GDCh app as well.
Nov 26, 2021	I updated the publication list to include whether an article is Open Access or not. Hopefully, many more to come!

selected publications

Macromolecules

Self-healing Functional Polymers: Optical Property Recovery of Conjugated Polymer Films by Uncatalyzed Imine Metathesis

Johannes Ahner, Mathias Micheel, Robert Geitner, Michael Schmitt, Jürgen Popp, Benjamin Dietzek, and Martin D. Hager

Macromolecules

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The implementation of a self-healing functionality into materials has become a prevalent approach for materials which require long-term reliability. As of today, the restoration of mechanical properties has dominated the research on self-healing materials, whereas research on healing of other functionalities (e.g., conductivity or optical properties) is still in its infancy. Here, the first conjugated polymer, which can restore its optical properties after photodamage is reported. The proposed self-healing mechanism relies on a thermally triggered imine metathesis between the conjugated polymer and additional macromolecular healing agents with no catalyst needed.
J. Phys. Chem. Lett.

Ultrafast Electron Transfer from CdSe Quantum Dots to an [FeFe]-Hydrogenase Mimic

Alexander Schleusener, Mathias Micheel, Stefan Benndorf, Markus Rettenmayr, Wolfgang Weigand, and Maria Wächtler

The Journal of Physical Chemistry Letters

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The combination of CdSe nanoparticles as photosensitizers with [FeFe]-hydrogenase mimics is known to result in efficient systems for light-driven hydrogen generation with reported turnover numbers in the order of 104–106. Nevertheless, little is known about the details of the light-induced charge-transfer processes. Here, we investigate the time scale of light-induced electron transfer kinetics for a simple model system consisting of CdSe quantum dots (QDs) of 2.0 nm diameter and a simple [FeFe]-hydrogenase mimic adsorbed to the QD surface under noncatalytic conditions. Our (time-resolved) spectroscopic investigation shows that both hot electron transfer on a sub-ps time scale and band-edge electron transfer on a sub-10 ps time scale from photoexcited QDs to adsorbed [FeFe]-hydrogenase mimics occur. Fast recombination via back electron transfer is observed in the absence of a sacrificial agent or protons which, under real catalytic conditions, would quench remaining holes or could stabilize the charge separation, respectively.
Adv. Mater. Interfaces

Assembly, Properties, and Application of Ordered Group II–VI and IV–VI Colloidal Semiconductor Nanoparticle Films

Mathias Micheel, Raktim Baruah, Krishan Kumar, and Maria Wächtler

Advanced Materials Interfaces

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Colloidal semiconductor nanocrystals, in particular cadmium and lead chalcogenide particles, are pivotal materials in many optoelectronic applications. While synthetic advances in the past decades now allow precise control of their size, shape, and composition, they must be processed from dispersion into functional films for many applications, which presents additional challenges. In this review, recent progresses in the field of nanoparticle self-assembly into functional thin films with precise control over nanoparticle order and orientation are discussed. A comprehensive overview on characterization methods used in the study of such ordered materials is provided and the gas–liquid interfacial self-assembly and electric field driven deposition as the two most promising ways to generate superstructures with defined thickness, order, and orientation are discussed. The superstructure–property relationships are then reviewed with emphasis on charge migration through the film and radiative processes. Last, challenges and open questions in the field are addressed.