Geuchies Jaco J, Klarbring Johan, Virgilio Lucia Di, Fu Shuai, Qu Sheng, Liu Guangyu, Wang Hai, Frost Jarvist M, Walsh Aron, Bonn Mischa, Kim Heejae
Max Planck Institute for Polymer Research, 55128 Mainz, Germany.
Department of Materials, Imperial College London, London SW7 2AZ, United Kingdom.
Nano Lett. 2024 Jul 17;24(28):8642-8649. doi: 10.1021/acs.nanolett.4c01905. Epub 2024 Jul 8.
Two-dimensional (2D) hybrid organic-inorganic metal halide perovskites offer enhanced stability for perovskite-based applications. Their crystal structure's soft and ionic nature gives rise to strong interaction between charge carriers and ionic rearrangements. Here, we investigate the interaction of photogenerated electrons and ionic polarizations in single-crystal 2D perovskite butylammonium lead iodide (BAPI), varying the inorganic lamellae thickness in the 2D single crystals. We determine the directionality of the transition dipole moments (TDMs) of the relevant phonon modes (in the 0.3-3 THz range) by the angle- and polarization-dependent THz transmission measurements. We find a clear anisotropy of the in-plane photoconductivity, with a ∼10% reduction along the axis parallel with the transition dipole moment of the most strongly coupled phonon. Detailed calculations, based on Feynman polaron theory, indicate that the anisotropy originates from directional electron-phonon interactions.
二维（2D）有机-无机杂化金属卤化物钙钛矿为基于钙钛矿的应用提供了更高的稳定性。其晶体结构的柔软性和离子性导致电荷载流子与离子重排之间存在强相互作用。在此，我们研究了单晶2D钙钛矿碘化丁基铵铅（BAPI）中光生电子与离子极化的相互作用，改变了2D单晶中的无机薄片厚度。我们通过角度和偏振相关的太赫兹传输测量确定了相关声子模式（在0.3 - 3太赫兹范围内）的跃迁偶极矩（TDM）的方向性。我们发现面内光电导率存在明显的各向异性，沿与最强耦合声子的跃迁偶极矩平行的轴方向降低约10%。基于费曼极化子理论的详细计算表明，这种各向异性源于定向的电子-声子相互作用。
