Optoelectronics Group, Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, UK.
Department of Chemistry and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Butenandtstraße 11, 81377 München, Germany.
Sci Adv. 2017 Jan 27;3(1):e1601935. doi: 10.1126/sciadv.1601935. eCollection 2017 Jan.
Fundamental understanding of the charge transport physics of hybrid lead halide perovskite semiconductors is important for advancing their use in high-performance optoelectronics. We use field-effect transistors (FETs) to probe the charge transport mechanism in thin films of methylammonium lead iodide (MAPbI). We show that through optimization of thin-film microstructure and source-drain contact modifications, it is possible to significantly minimize instability and hysteresis in FET characteristics and demonstrate an electron field-effect mobility (μ) of 0.5 cm/Vs at room temperature. Temperature-dependent transport studies revealed a negative coefficient of mobility with three different temperature regimes. On the basis of electrical and spectroscopic studies, we attribute the three different regimes to transport limited by ion migration due to point defects associated with grain boundaries, polarization disorder of the MA cations, and thermal vibrations of the lead halide inorganic cages.
对混合卤化铅钙钛矿半导体的电荷输运物理的基本理解对于推进其在高性能光电中的应用非常重要。我们使用场效应晶体管（FET）来探测薄膜碘化甲基铵铅（MAPbI）中的电荷输运机制。我们表明，通过优化薄膜微结构和源漏接触的改进，可以显著减小 FET 特性中的不稳定性和滞后，并在室温下实现 0.5 cm/Vs 的电子场效应迁移率（μ）。温度相关的输运研究揭示了三个不同温度区域的负迁移率系数。基于电学和光谱学研究，我们将三个不同的区域归因于由于与晶粒边界相关的点缺陷、MA 阳离子的极化无序以及卤化铅无机笼的热振动引起的离子迁移限制的输运。
