Wang Shuanglong, Gao Lei, Mandal Mukunda, Wu Hao, Ling Zhitian, Bonn Mischa, Andrienko Denis, Blom Paul W M, Wang Hai I, Pisula Wojciech, Marszalek Tomasz
Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
Nanophotonics, Debye Institute for Nanomaterials Research, Utrecht University, Princetonplein 1, 3584 CC, The Netherlands.
Mater Horiz. 2025 Aug 26;12(17):6812-6821. doi: 10.1039/d5mh00335k.
Two-dimensional (2D) perovskites have emerged as promising candidates for field-effect transistors (FETs) due to their pronounced stability in the presence of insulating bulky organic spacer cations. However, the underlying mechanism of the charge carrier transport in these 2D perovskite semiconductors remains elusive. In this study, the temperature dependence of the charge carrier properties of benzimidazolium tin iodide perovskite ((Bn)SnI) is studied to evaluate the corresponding transport mechanism on nanoscopic and macroscopic dimensions. By combination of solvent engineering to optimize the morphology of perovskite thin films and choice of the organic imidazole-based spacer inducing hydrogen bonding with the inorganic [SnI] octahedron layer, less ionic defects are generated resulting in suppressed ion movement. It was possible to separate the influence of mobile ions and temperature on the charge carrier transport in transistors. The decline of the charge carrier mobility with temperature decrease in the device indicates a hopping mechanism for macroscopic transport. On the other hand, the local charge transport was determined by ultrafast terahertz photoconductivity measurements revealing an increasing mobility to 17 cm V s with temperature decrease implying a band mechanism on the nanoscopic scale. The local charge carrier mobility is associated with the particularly regular structure of the octahedral [SnI] sheets induced by symmetric hydrogen bonding with the benzimidazolium cation. Our results provide key insights on the charge transport properties of perovskite semiconductors, which have important implications for realizing high-performance electronic devices.
二维（2D）钙钛矿由于在存在绝缘性大体积有机间隔阳离子的情况下具有显著的稳定性，已成为场效应晶体管（FET）的有前途的候选材料。然而，这些二维钙钛矿半导体中载流子传输的潜在机制仍然难以捉摸。在本研究中，研究了苯并咪唑锡碘钙钛矿（（Bn）SnI）的载流子特性对温度的依赖性，以评估在纳米和宏观尺度上相应的传输机制。通过结合溶剂工程来优化钙钛矿薄膜的形貌以及选择与无机[SnI]八面体层形成氢键的有机咪唑基间隔体，产生的离子缺陷较少，从而抑制了离子移动。有可能分离出移动离子和温度对晶体管中载流子传输的影响。器件中载流子迁移率随温度降低而下降，这表明宏观传输存在跳跃机制。另一方面，通过超快太赫兹光电导率测量确定了局部电荷传输，结果显示随着温度降低迁移率增加至17 cm² V⁻¹ s⁻¹，这意味着在纳米尺度上存在能带机制。局部载流子迁移率与由与苯并咪唑阳离子的对称氢键诱导的八面体[SnI]片层的特别规则结构有关。我们的结果为钙钛矿半导体的电荷传输特性提供了关键见解，这对实现高性能电子器件具有重要意义。
