Credit: Artem Musiienko (Charles University)
UTK MSE Assistant Professor Mahshid Ahmadi is fascinated with the exotic physics and chemistry of hybrid perovskites and how to manipulate their properties for more efficient optoelectronic devices. Her recent studies have resulted in two published articles in the high impact journal, Science Advances, in the past three months. Dr. Ahmadi is the corresponding author on both articles, which report on research performed in collaboration with Oak Ridge National Laboratory, Charles University in Prague, Lawrence Berkeley National Laboratory, and the University of California, Berkeley. “Giant isotope effect on phonon dispersion and thermal conductivity in methylammonium lead iodide” appeared in July and “Deciphering the effect of traps on electronic charge transport properties of methylammonium lead tribromide perovskite” followed quickly in September (click the title to read each article).
In the first study, Ahmadi and her collaborators at ORNL showed that tuning the organic-molecule dynamics through isotope exchange induces a 50% reduction in the already ultralow thermal conductivity of hybrid perovskites and increases the hot carrier lifetime which can enable hot carrier solar cells with the possibility of higher efficiency.
In the second study, her team demonstrated the parameters of defects in particular trapping and de-trapping activity and their interplay with free charge carriers in hybrid perovskites for the first time. This understanding is critical for designing hybrid perovskites for sensing applications.