Yin Wen-Yu, Weng Yi-Gang, Jiang Miao, Yu Shuai-Kang, Zhu Qin-Yu, Dai Jie
College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, People's Republic of China.
Key Laboratory of Advanced Functional Materials; School of Chemistry & Materials Engineering, Changshu Institute of Technology, Changshu 215500, People's Republic of China.
Inorg Chem. 2020 Apr 6;59(7):5161-5169. doi: 10.1021/acs.inorgchem.0c00386. Epub 2020 Mar 18.
Most large organic cations in the low-dimensional hybrid halide perovskites deteriorate the photoelectric conversion efficiency of the cells. Integrating electronically active organic components into hybrid metal halides is an effective method to improve their photoelectric properties. In this work, a series of compounds obtained by hybridizing redox-active tetrakis(methylthio)tetrathiafulvalene (TMT-TTF) with bismuth chloride, formulated as [TMT-TTF][BiCl] ( and ), [TMT-TTF][BiCl] (), [TMT-TTF][BiCl] (), [TMT-TTF][BiCl] (), and {[TMT-TTF][BiCl]} (), were crystallographically characterized. These hybrids exhibit changeable oxidation states of the TTF moiety. The radical cation TTF exists in and , while a mixed-valence TTF/TTF appears in that has never been documented in any compounds and the dication TTF exists in - that has never been introduced into hybrid organic-inorganic materials. The different charged states of the TTF cations lead to various degrees of connectivity of metal chloride anions, which exert a significant effect on the cation-anion arrangement and result in different supramolecular interactions between TMT-TTF and between cations and anions. The changeable oxidation states of the TTF moiety and varying degrees of metal chloride connectivity provide a good comparison among these hybridized bismuth chlorides. The order of conductivity is > > > ≈ ≫ , which results from the synergistic effect of different oxidation states, the packing of TMT-TTF cations, and back charge transfer from the Bi-Cl anion to the TMT-TTF cation. Notably, the electrical conductivity and carrier mobility can be modulated with the fact that compound has the highest performances in the dark, while in light, these properties of and are in turn higher than that of . The order of the photocurrent densities is in accordance with the increase of carrier mobility under irradiation of light. This work is the first systematic study of hybrid metal halides with various oxidation states of TTFs and presents a clear structure-property relationship and offers a fresh view on the design of new perovskite materials at the molecular level.
大多数低维混合卤化物钙钛矿中的大型有机阳离子会降低电池的光电转换效率。将具有电子活性的有机成分整合到混合金属卤化物中是改善其光电性能的有效方法。在这项工作中，通过将氧化还原活性的四（甲硫基）四硫富瓦烯（TMT-TTF）与氯化铋杂交得到了一系列化合物，其化学式为[TMT-TTF][BiCl]（和）、[TMT-TTF][BiCl]（）、[TMT-TTF][BiCl]（）、[TMT-TTF][BiCl]（）和{[TMT-TTF][BiCl]}（），并对其进行了晶体学表征。这些杂化物表现出TTF部分可变的氧化态。自由基阳离子TTF存在于和中，而混合价态的TTF/TTF出现在中，这在任何化合物中都未曾有过记录，并且二价阳离子TTF存在于中，这从未被引入到有机-无机混合材料中。TTF阳离子的不同电荷状态导致金属氯化物阴离子的连接程度不同，这对阳离子-阴离子排列产生显著影响，并导致TMT-TTF之间以及阳离子与阴离子之间不同的超分子相互作用。TTF部分可变的氧化态和不同程度的金属氯化物连接性为这些混合氯化铋之间提供了很好的比较。电导率顺序为> > > ≈ ≫ ，这是由不同氧化态、TMT-TTF阳离子的堆积以及从Bi-Cl阴离子到TMT-TTF阳离子的反向电荷转移的协同效应导致的。值得注意的是，电导率和载流子迁移率可以通过以下事实进行调节：化合物在黑暗中具有最高性能，而在光照下，和的这些性能又高于。光电流密度顺序与光照下载流子迁移率的增加一致。这项工作是对具有不同氧化态TTF的混合金属卤化物的首次系统研究，呈现了清晰的结构-性能关系，并在分子水平上为新型钙钛矿材料的设计提供了新的视角。
