Soft Matter Physics and Optoelectronics Group at University of Potsdam

White light generation in our transient absorption setup
Photo: Jona Kurpiers
White light generation in our transient absorption setup

The research of the “Soft Matter Physics and Optoelectronics” group is concerned with understanding the physical processes in soft matter semiconductors, including organic and more recently organo-metallic perovskite semiconductors, and at their interfaces with inorganic semiconductors and metals.

Our particular focus is on the nature and dynamics of excitations and charges in these systems, with the goal of improving their performance in electronic and optoelectronic applications. The group has therefore installed a variety of transient techniques, designed to follow the fate of these excitations in functional devices on all relevant time scales, from sub-picoseconds through steady state. The group is particularly known for our time-delayed collection field setup, which is unique with regard to temporal resolution and sensitivity, but we also make use of various all-optical techniques including steady state and time resolved fluorescence spectroscopy and femtosecond transient absorption. The results of these measurements serve as inputs for extensive drift-diffusion simulations, and for the development of analytical models to describe the function of entire devices.

With this knowledge at hand, materials and device structures are further optimized, with the prospect to push the optoelectronic performance parameters beyond current limits.


Cover fragment of Arvind Journal of Physical Chemistry B 2020

Malavika's recent paper made the cover of Journal of Physical Chemistry B: Doping-induced delocalized polarons, localized polarons, and charge-transfer complexes of P3HT in solution. Investigation of molecular doping of regioregular and regiorandom poly(3-hexylthiophene) in solution by UV–vis–NIR and EPR spectroscopies led to identification of delocalized polarons, localized polarons, and charge-transfer complexes depending on the disorder of the P3HT backbone and the used dopant molecule.

A recent Progress Review of the group, published in Advanced Materials, deals with the understanding and suppression of interfacial non-radiative recombination in perovskite solar cells. The paper is published open access.