Two-dimensional metal halide perovskites (2D-MHPs) are chemically and structurally diverse semiconducting materials with promising applications in photovoltaics and optoelectronics. The understanding of charge and heat transport is crucial for improving the performance and stability of devices made from these materials. I will discuss our recent efforts on developing time-resolved optical spectroscopy and imaging techniques for characterizing heat flow in these hierarchically architecture materials. I will then demonstrate how we might turn the generally poor thermal transport property of these materials into a desirable characteristic, where we employ these materials for thermal-type photodetectors of long-wavelength light. If time permits, I will also present our efforts on the understanding of phase transitions and light-induced structural dynamics in MHPs at intrinsic time and length scales.
Peijun Guo received his B.S. from Tsinghua University, China, with highest honors in 2009, and his M.S. and Ph.D. from Northwestern University in 2011 and 2016, respectively, all in materials science and engineering. After spending three years at Argonne National Lab as an Enrico Fermi Named Postdoc Fellow, Peijun joined the Department of Chemical and Environmental Engineering at Yale University, with his lab hosted under the Energy Sciences Institute on Yale’s west campus. The Guo group develops and employs optical spectroscopy and microscopy methods to understand the structure-property relationships in emerging hybrid and low-dimensional materials. His lab is also interested in finding new applications for these emerging, solution-processable materials by tailoring light-matter interactions at the nanoscale. He has been awarded the AFOSR Young Investigator and the ACS PRF Doctoral New Investigator.