Department Solution Processing of Hybrid Materials & Devices
Pillar 3: Process Rationalization
Over the last years, the unger team developed small footprint tools to measure optical and x-ray-based features in-situ.
Our goals is to uderstand the formation from the ink to the final film. Thus, we correlate structure-property features and rationalize the formation process and design better inks & processes.
Optical In situ monitoring
We use a lab-made optical metrology system during coating, printing and annealing to reveal the formation kinetics. The setup measures in situ absorption and photoluminescence in below 1 sec time resolution. [link]
In situ x-ray spectroscopy
We use various x-ray methods to get structural informations of the processed film. We have established in situ gracing incident wide angle x-ray scattering (GIWAXS) in cooperation with @ BessyII beamline scientists.
In the INFORM project, we have developed a roll-to-roll slot-die coater mounted at MAX-IV. [link]
Mixed halide perovskites
We are highly investigating mixed halide perovskites, especially iodide-bromide compositional range.
We identified competing formations via the bromide-rich perovskite phase and iodide-rich intermediate solvate phase [link].
Under illumination, we observed a multi-stage phase-segregation [link].
Furthermore, we identify delayed nucleation and retarded growth kinetics for more concentrated precursor solutions. Colloids are pre-organised to a higher degree and higher-coordination lead–bromide complexes tend to form in more concentrated precursor solutions [link].