This PhD position is supported by a DFG project ‘Field-enhanced spectroscopy on photoactive hybrid metallic/semiconducting nanostructures’. This is a trilateral collaboration project among Germany, Poland, and Czech Republic. The project starts from the beginning of 2025.

Nowadays, advanced nanomaterials designed for nanophotonics, energy storage/conversion, catalysis, sensors, etc. combine the extraordinary properties of hybrid nanostructured semiconductor and plasmonic metallic/semiconducting nanoantennas. This project aims to explore phenomena occurring at the interface of plasmonic (Ag, Au) nanoantennas and photoactive materials, particularly inorganic semiconductors, and to correlate these processes with optical and photoelectrochemical functions. The photosensitivity of the hybrid nanomaterials depends on the geometry, chemical composition, and the synergy of the components’ properties. Their interface and surface features can be probed by field-enhanced spectroscopy, in particular, by vibrational surface-enhanced (SERS), photo-induced Raman spectroscopy (PIERS), and tip-enhanced (TERS) Raman spectroscopy. Closely working together with the collaboration partners, the PhD candidate will reveal the variations in the charge-transfer processes between the individual antennas of different materials and geometries with the underlying semiconducting layer using PIERS and TERS at the nanometre scale. 

For more details, please contact Prof. Dai Zhang (dai.zhang-at-uni-tuebingen.de; Tel.: 070712977639)

Optical spectroscopy is routinely used to analyze chemical structures of organic molecules. However, generally the optical resolution is limited by diffraction to roughly half a wavelength that is much larger than the molecular dimension. One of the most prominent techniques to overcome this bottleneck is tip-enhanced Raman spectroscopy (TERS), which allows the spatial resolution with chemical identification capability down to ~5 Å. The ability of such Angstrom-resolved spatial resolution to determine the chemical structure of unknown molecules arouse intense interests in the fields of chemistry, physics, materials, and biology. Our group is one of the pioneer groups in this exciting field. We continuously implement new optical techniques into TERS and surface-enhanced Raman spectroscopy in order to study the local morphology related optical properties of semiconducting small molecules, push-pull chromophores, and plasmonic metal nanostructures.

This HiWi position is located in a newly granted DFG project ‘Angular resolved optical emission from adsorbates in (sub)nanometer gap’. The tasks for the student assistants consist of three parts: 

1) The student assistant will prepare ultrasmooth gold film and microcrystalline Au (111) thin film according to a reported protocol. 

2) The student assistant will perform enhanced Raman spectroscopy on semiconducting thin films that are deposited on the above prepared gold films. 

3) The student assistant will be responsible for the preparation of high-quality gold tips by electrochemical etching according to our protocol and their characterization by SEM.

For more details, please contact Prof. Dai Zhang (dai.zhang-at-uni-tuebingen.de; Tel.: 070712977639)

Layered transition metal dichalcogenides (2D-TMDCs) have emerged as a promising alternative to mainstream semiconductor materials (e. g. silicon) for application in modern semiconductor devices for electronics, lighting, solar energy and communication. The electronic structures of TMDCs are sensitive to external perturbations, such as changing the number of layers, the level of strain, or the surface chemistry. Metal phthalocyanines (MPcs) may take a leading role in tailoring the optoelectronic properties of 2D-TMDCs via molecular adsorption.

The goal of the project is the tuning of the electronic properties of TMDCs by the adsorption of molecules. Here, the effects of the electronic structure tuning will be inspected using photoluminescence, Raman and second harmonic generation microscopy, at sub-micrometer and nanometer scales.

Nowadays, microplastic particles (< 5 mm) have been ubiquitously detected in the environments (figure 1 a). The impacts of plastic particles on organisms are categorized as physical effects and chemical effects. Whilst the former is related to the particle size, shape, and concentration, the latter is associated to the hazardous chemicals in microplastics. With particle size of less than 1 micrometer, nanoplastics typically resulted from degradation and fragmentation of microplastics. Though data on microplastic exposure levels in environments and organisms have rapidly increased in recent decades, limited information associated with nanoplastics is available. They are probably the least known area of plastic litter but are suspected to pose the greatest risk to the environment. In this project we will develop effective optical spectroscopic methods to identify the chemical composition of nanoplastics and correlating their physical appearances.