Wang Qian, Lu Ying, He Rui-Lin, Chen Ruyi, Qiao Leilei, Pan Feng, Yang Zhou, Song Cheng
Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China.
Department of Materials Physics and Chemistry, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
Small Methods. 2022 Dec;6(12):e2201048. doi: 10.1002/smtd.202201048. Epub 2022 Nov 20.
Introducing chirality into low-dimensional hybrid organic-inorganic halides (HOIHs) creates brand-new opportunities for HOIHs in spintronics and spin-related optoelectronics owing to chirality-induced spin selectivity (CISS). However, preparing smooth films of low-dimensional HOIHs with small roughness is still a great challenge due to the hybrid and complex crystal structure, which severely inhibits their applications in spintronic devices. Exploring new lead-free chiral HOIHs with both efficient spin selectivity and excellent film quality is urgently desired. Here, cobalt-based chiral metal halide crystals (R/S-NEA) CoCl constructed by 0D [CoCl ] tetrahedrons and 1-(1-naphtyl)ethylamine (NEA) are synthesized. The orderly configuration of NEA molecules stabilized by noncovalent CH···π interaction endows (NEA) CoCl with good film-forming ability. (NEA) CoCl films exhibit strong chiroptical activity (g ≈ 0.05) and significant spin-polarized transport (CISS efficiency up to 90%). Furthermore, ultrasmooth films (roughness ∼ 0.3 nm) with enhanced crystallinity can be achieved by incorporating tiny amount tris(8-oxoquinoline)aluminum that has analogous conjugated structure to NEA. The realization of highly efficient spin selectivity and sub-nanometer roughness in lead-free chiral halides can boost the practical process of low-dimensional HOIHs in spintronics and other fields.
由于手性诱导自旋选择性（CISS），将手性引入低维有机-无机杂化卤化物（HOIHs）为其在自旋电子学和自旋相关光电子学领域创造了全新机遇。然而，由于其混合且复杂的晶体结构，制备具有低粗糙度的光滑低维HOIHs薄膜仍是一项巨大挑战，这严重限制了它们在自旋电子器件中的应用。迫切需要探索兼具高效自旋选择性和优异薄膜质量的新型无铅手性HOIHs。在此，合成了由零维[CoCl]四面体和1-（1-萘基）乙胺（NEA）构建的钴基手性金属卤化物晶体（R/S-NEA）CoCl。通过非共价CH···π相互作用稳定的NEA分子的有序构型赋予（NEA）CoCl良好的成膜能力。（NEA）CoCl薄膜表现出强烈的圆二色活性（g≈0.05）和显著的自旋极化传输（CISS效率高达90%）。此外，通过掺入少量与NEA具有类似共轭结构的三（8-羟基喹啉）铝，可以获得具有增强结晶度的超光滑薄膜（粗糙度约为0.3nm）。无铅手性卤化物中高效自旋选择性和亚纳米粗糙度的实现可以推动低维HOIHs在自旋电子学及其他领域的实际应用进程。
