Phonon鈥揈lectron Scattering Limits Free Charge Mobility in Methylammonium Lead Iodide Perovskites

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• 作者：Melike Karakus ; S酶ren A. Jensen ; Francesco D鈥橝ngelo ; Dmitry Turchinovich ; Mischa Bonn ; Enrique C谩novas
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2015
• 出版时间：December 17, 2015
• 年：2015
• 卷：6
• 期：24
• 页码：4991-4996
• 全文大小：372K
• ISSN：1948-7185

文摘

The nature of the photoconductivity in solution-processed films of methylammonium lead iodide perovskite is investigated by determining the variation of the photoconductive response with temperature. Ultrabroadband terahertz (THz) photoconductivity spectra in the 0.3鈥?0 THz range can be reproduced well by a simple Drude-like response at room temperature, where free charge carrier motion is characterized by an average scattering time. The scattering time determined from Drude fits in the 0.3鈥?THz region increases from 鈭? fs at 300 K (tetragonal phase; mobility of 鈭?7 cm² V^鈥? s^鈥?) to almost 鈭?5 fs at 77 K (orthorhombic phase, mobility of 鈭?50 cm² V^鈥? s^鈥?). For the tetragonal phase (temperature range 150 < T < 300 K) the scattering time shows a 鈭?i>T^鈥?/2 dependence, approaching the theoretical limit for pure acoustic phonon (deformation potential) scattering. Hence, electron鈥損honon, rather than impurity scattering, sets the upper limit on free charge transport for this perovskite.