Operando

Traditional structural characterization of materials is often done ex-situ, where the samples are measured before and after formation or operation.  This approach, though insightful, misses a large amount of information on what is happening to the sample between end points.  Synchrotron sources with their high flux coupled with advances in detector technology have reduced collection times for X-ray diffraction (XRD) experiments making in-situ data collection possible.  These advances in structural characterization can provide greater insight into the formation and operation of photovoltaic materials (PV) and devices.

Out group has developed methods for the simultaneous characterization of the structural properties of PV materials via XRD while also monitoring the device performance.

Currently this work has focused on hybride perovskite solar cells.  These are a class of materials with the pervoskite, AMX3 crystal structure where A is the monovalent cation (methyl ammonium, MA, formamidinium, FA, Rb, and/or Cs), M is the metal cation (Pb2+), and X is the halide anion (I, Cl, and/or Br). Using this operando approach our group explores the structural stability of these materials during operation under numerous different stressors including but not limited to: heating, cooling, and/or humidity exposure.  

Future research in using these methods to explore other PV materials and components is of interest.