RECENT NEWS
10.02.2019 - Following up his recent podcast appearance, Tim Siegler will be giving a talk as a part of the UT Energy Symposium. Tim's talk, "The 10th Birthday of Perovskite Solar Cells - Will They Ever Grow Up?", will take place on October 10th. Interested attendees can register here.
09.27.2019 - Congrats to Korgel Group alumni and current professor at National Tsing Hua University in Taiwan, Dr. Hsing-Yu Tuan, for receiving the prestigious "Award for Outstanding Asian Researcher and Engineer" presented by the Society of Chemical Engineering of Japan. Great work, Hsing-Yu!
07.12.2019 - Big welcome to all the new visitors and undergrads joining us in the lab this summer! We have REU students, teachers through RET, visiting international grad and undergrad students, Austin Community College students, and of course UT undergrads. Welcome to the Korgel Group!
07.02.2019 - Check out the new paper from the Korgel Group in ACS Applied Nano Materials, where Dan Houck et al. show phase control in the copper indium gallium selenide (CIGSe) system, and demonstrate how they can yield nanocrystals of the metastable CIGSe wurtzite phase. Link
06.20.2019 - New paper from the Korgel Group! In the Journal of Physical Chemistry C, Yangning Zhang et al. explore phase transitions in superlattices of MAPI nanocrystals. Link
05.07.2019 - Congratulations to Wen Liu, who successfully passed her candidacy exam, entitled "Tuning Mechanical Properties of CuInSe2 Nanocrystals via Ligand Exchange and Application in Elastic Solar Cells"!
RESEARCH HIGHLIGHT
Thermal Phase Transitions in Superlattice Assemblies of Cuboidal CH3NH3PbI3 Nanocrystals Followed by Grazing Incidence X-ray Scattering
Methylammonium lead iodide (CH3NH3PbI3, or MAPI) is a prototypical lead halide perovskite material with promising optoelectronic properties for solar cells and light-emitting devices. In this paper, Yangning Zhang, Cherrelle Thomas, and Adrien Guillaussier reported the thermal phase transitions that occur in superlattices of MAPI nanocrystals observed using in-situ grazing incidence small-angle and wide-angle X-ray scattering (GISAXS and GIWAXS). GIWAXS shows that the nanocrystals have completed a tetragonal-to-cubic phase transition at 55-60C similar to bulk films and begin to degrade at 90C, when PbI2 begins to form. Both hexagonal and rhombohedral phases of PbI2 are observed as thermal degradation products at 150C. GISAXS shows that the superlattice remains stable until 90C. This work was done in collaboration with Dr. Smilgies at Cornell High Energy Synchrotron Source (CHESS) and was recently published in the Journal of Physical Chemistry C.
