Prof. Thomas Bein, Department of Chemistry, Ludwig-Maximilians-Universität München (LMU) 

Project:

The search for sustainable energy sources will become ever more important during this century. We investigate the bottom-up assembly of semiconductor nano-morphologies, ultimately aimed at understanding and optimizing the key processes in photovoltaic devices. The control of nanoscale morphology is also of great importance for the design of efficient novel photovoltaic devices. This project aims at the design and use of nanoscale semiconducting building blocks for the template-directed assembly of such nano-morphologies. This approach allows us to create nanoporous networks of various morphologies and pore sizes, which are ideal model systems for the investigation of photovoltaic devices. For example, we use non-aqueous sol-gel protocols for the synthesis of nanoscale transition metal oxide particles such as titania. The nanoparticles are being used for the preparation of thin porous films that are integrated into dye-sensitized and related photovoltaic devices. 

The candidate will structurally characterize the materials by methods such as small-angle X-ray scattering (SAXS), gas sorption and vibrational spectroscopy. Electron microscopy will be used to obtain images of the samples both by scanning the surface (SEM) and in high-resolution transmission mode (TEM). Furthermore, the candidate will be involved in the assembly and detailed characterization of dye-sensitized and solid hole-conductor solar cells. The transport properties of the porous networks and the dynamics of the light-induced charge carriers will also be studied. 

Literature:

1      Fattakhova-Rohlfing, D. et al. Low-Temperature Synthesis of Mesoporous Titania-Silica Films with Pre-Formed Anatase Nanocrystals. Chem. Mater. 21, 2410-2417 (2009).

2     Szeifert, J. M. et al. "Brick and Mortar" Strategy for the Formation of Highly Crystalline Mesoporous Titania Films from Nanocrystalline Building Blocks. Chem. Mater. 21, 1260-1265 (2009).

3      Mandlmeier, B., Szeifert, J. M., Fattakhova-Rohlfing, D., Amenitsch, H., Bein, T. Formation of Interpenetrating Hierarchical Titania Structures by Confined Synthesis in Inverse Opal, J. Am. Chem. Soc. 133,17274 (2011).

4     Liu, Y. J. et al. Niobium-Doped Titania Nanoparticles: Synthesis and Assembly into Mesoporous Films and Electrical Conductivity. ACS Nano 4, 5373-5381 (2010).

5     Nemec, H. et al. Tuning the Conduction Mechanism in Niobium-Doped Titania Nanoparticle Networks. J. Phys. Chem. C 115, 6968-6974 (2011).

6     Szeifert, J. M. et al. Ultrasmall Titania Nanocrystals and Their Direct Assembly into Mesoporous Structures Showing Fast Lithium Insertion. J. Am. Chem. Soc. 132, 12605-12611 (2010).

More information about the group:

Prof. Bein's webpage