Tuning energy transfer and charge carrier dynamics in perovskite systems for application in photovoltaics and optoelectronics

• Applicant: Professor Dr. Josef Wachtveitl
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry ; Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 557840081

Today, when climate change has become a serious problem, renewable energies are getting more important. Their widespread utilization requires further progress in terms of material properties and manufacturing costs. Solar energy is considered to have the greatest potential among renewable energy sources. The more efficient conversion of solar energy into electricity using more cost-effective materials and simpler methods is at the center of renewable energy research. The development of the material ‘perovskite’ has made enormous progress in recent years. Lead halide perovskite solar cells (PSCs) in particular are promising semiconductor materials with tunable optical and electrical properties, structural flexibility and low-cost production. Three-dimensional (3D) perovskites have shown outstanding progress in the energy conversion efficiency of solar cells from 3.8 % to 25.2 % within the last decade. Two-dimensional (2D) organic-inorganic perovskites are also relevant for many important optoelectronic applications. The high excitonic binding energy of 2D perovskites allows their use in LED applications and their stability in relation to environmental influences (moisture, oxygen, ...) is superior to that of 3D perovskites. The main objective of this project is to investigate the potential of specifically modified perovskites for their application in optoelectronics and photovoltaics. This goes hand in hand with a detailed understanding of the primary photochemical dynamics. The key tasks of this project include i) the preparation and characterization of customized, photoresponsive 2D and 3D perovskites, ii) the investigation of different chromophore cations/cation mixtures, in particular with regard to energy transfer and exciton dynamics, iii) the comparison of Frenkel and Wannier-Mott excitons (2D) under systematic energy variation up to the resonance case, iv) the investigation of polaron formation and charge carrier dynamics in wide bandgap perovskites. The project covers a wide range of topics from ligand design to real-time observation of ultrafast photodynamics. It provides the ideal framework for the development and characterization of new materials with high efficiency of specifically optimized nanostructures for their application as renewable energy sources.

• DFG Programme: Research Grants