Transient Absorption Spectroscopy and 2D Semiconductors

Using wet-chemical synthesis methods associated to the ones applied for 0D nanocrystals, we obtain 2D semiconductors with a thickness of mono- or few-layers. By guiding the reaction via surface ligands and growth control, anisotropic ultrathin 2D layers of typically isotropically crystallizing semiconductor systems synthesized that are not accessible by exfoliation methods.

Depending on their lateral size, the so-called nanosheets or nanoplatelets have intriguing optoelectronic properties that are caused by their strong size quantization in one dimension, their thickness.

E.g. under photoexcitation, strongly bound electron-hole pairs, so-called excitons, are generated in nanosheets and nanoplatelets, which can emit light of a certain wavelength when recombining and have high potential for light-emitting diodes or even lasing. Furthermore, highly mobile free charge carriers can be photogenerated, which are needed for fast switching transistors, photodetectors or solar cells.

We obtain colloidal 2D semiconductor inks that can be processed easily onto different surfaces, substrates and cover the UV-Vis region up to the NIR/SWIR in terms of absorption and emission.