Energy conversion materials

We work on the understanding and optimization of materials for photovoltaic applications and luminescent materials like organic light emitting diodes. To this end, a combination of first-principles TDDFT, approximate TD-DFTB frequency domain and real time approaches are used. Our goal is a consistent description of exciton generation, migration and decay at the microscopic level.

Studies in the field of photophysics and -chemistry quite often target at eigenstates of the system at fixed geometry. Many applications require however an understanding of the dynamics that follow an initial excitation rather than a static picture that blinds out all relaxation paths that lead to the population of a given excited state. In dye sensitized solar cells (DSSC), as an example, the spatial separation of electrons and holes is the result of a complex and highly non-trivial chain of excited state processes. Sun light promotes the generation of a localized exciton on dyes, that are adsorbed on semiconductor nanoparticles. The excited electron is subsequently transferred to the conduction band of the semiconductor and diffuses through a network of nanoparticles to the electrode. In organic light emitting diodes (OLED) the opposite process occurs. Injected electrons and holes pass layers of tailored materials to eventually form localized excitons and recombine on emitters. These complex dynamical processes are currently poorly understood and our goal is to shed some light on these events by time dependent simulations.


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Project related publications


Upcycling polyethersulfones to luminescent materials by aminolysis
Liotier, J., Alfari, L.I., Mahler, B., Niehaus, T.A., Dujardin, C., Guelen, S., Schanen, V., Dufaud, V., Raynaud, J., and Monteil, V.
Polym. Chem. 16, 1139 (2025)

P\N Bridged Cu(I) Dimers Featuring Both TADF and Phosphorescence. From Overview towards Detailed Case Study of the Excited Singlet and Triplet States
Hofbeck, T., Niehaus, T.A., Fleck, M., Monkowius, U., and Yersin, H.
Molecules 26, 3415 (2021)

Dynamic Characteristics of Aggregation Effects of Organic Dyes in Dye-Sensitized Solar Cells
Feng, S., Li, Q., Sun, P., Niehaus, T. und Li, Z.
ACS Appl. Mater. Interfaces 7, 22504 (2015)

Charge-transfer excited states in phosphorescent organo-transition metal compounds: a difficult case for time dependent density functional theory?
Niehaus, T., Hofbeck, T. und Yersin, H.
RSC Advances 5, 63318 (2015)

Efficient Emission Facilitated by Multiple Energy Level Transitions in Uniform Graphitic Carbon Nitride Films Deposited by Thermal Vapor Condensation
Bian, J., Li, J., Kalytchuk, S., Wang, J., Li, Q., Lau, T., Niehaus, T., Rogach, A. und Zhang, R.
ChemPhysChem 16, 954 (2015)

Sub-Nanometer Width Armchair Graphene Nanoribbon Energy Gap Atlas
Palma, C., Awasthi, M., Hernandez, Y., Feng, X., Müllen, K., Niehaus, T. und Barth, J.
The Journal of Physical Chemistry Letters 6, 3228 (2015)

Unsymmetrical squaraine dye containing dithieno[3,2-b:2′,3′-d]pyrrole as a π-spacer: A potential photosensitizer for dye-sensitized solar cells
Yang, L., Sun, Z., Li, Q., Chen, S., Li, Z. und Niehaus, T.
Journal of Power Sources 268, 137-145 (2014)