As a light absorber in photovoltaic applications, hybrid organic-inorganic halide perovskites should have long and balanced diffusion lengths for both the separated electrons and holes before recombination, which necessitates high carrier mobility. In polar semiconductors, the roomerature carrier mobility is often limited by the scattering between carriers and the lowest-frequency optical phonon modes. Using terahertz time-domain spectroscopy, we examine the temperature evolution of these phonon modes in CH3NH3PbBr3 and obtained high carrier mobility values using Feynman's polaron theory. This method allows us to estimate the upper limit of carrier mobilities without the need to create photogenerated free carriers, and can be applied to other heteropolar semiconductor systems with large polarons.
Bibliographical noteFunding Information:
D.M.Z. acknowledges support from TUM-CREATE. E.E.M.C. acknowledges support from the Singapore Ministry of Education AcRF Tier 1 (RG123/14) and Tier 2 (MOE2015-T2-2-065 and MOE2016-T2-1-054). C.L. acknowledges support from the Theoretical and Computational Science (TaCS) Center and Thailand Research Fund (MRG6080264). R.A.M. thanks the ONR and ARO for their support. M.-E.M.-B. is grateful to the Nanyang Technological University for supporting the Biophysics Center. The work was supported in part by the Center for Integrated Nanotechnologies, a U.S. DOE BES user facility. J.M.S. is grateful for support from the UK Engineering and Physical Sciences Research Council (EPSRC; Grant No. EP/P007821/1). Calculations were performed on the SiSu supercomputer at the IT Center for Science (CSC), Finland, via the Partnership for Advanced Computing in Europe (PRACE) Project No. 13DECI0317/ IsoSwitch.
© 2017 Author(s).