Fraxedas Jordi, Vollmer Antje, Koch Norbert, de Caro Dominique, Jacob Kane, Faulmann Christophe, Valade Lydie
Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
Helmholtz Zentrum Berlin Materialien & Energie GmbH BESSY, D-12489 Berlin, Germany.
Materials (Basel). 2021 Apr 19;14(8):2058. doi: 10.3390/ma14082058.
The metallic and semiconducting character of a large family of organic materials based on the electron donor molecule tetrathiafulvalene (TTF) is rooted in the partial oxidation (charge transfer or mixed valency) of TTF derivatives leading to partially filled molecular orbital-based electronic bands. The intrinsic structure of such complexes, with segregated donor and acceptor molecular chains or planes, leads to anisotropic electronic properties (quasi one-dimensional or two-dimensional) and morphology (needle-like or platelet-like crystals). Recently, such materials have been synthesized as nanoparticles by intentionally frustrating the intrinsic anisotropic growth. X-ray photoemission spectroscopy (XPS) has emerged as a valuable technique to characterize the transfer of charge due to its ability to discriminate the different chemical environments or electronic configurations manifested by chemical shifts of core level lines in high-resolution spectra. Since the photoemission process is inherently fast (well below the femtosecond time scale), dynamic processes can be efficiently explored. We determine here the fingerprint of partial oxidation on the photoemission lines of nanoparticles of selected TTF-based conductors.
基于电子给体分子四硫富瓦烯（TTF）的一大类有机材料的金属性和半导体特性，源于TTF衍生物的部分氧化（电荷转移或混合价态），这导致基于分子轨道的电子能带部分填充。这类配合物的固有结构，具有分离的供体和受体分子链或平面，导致各向异性的电子性质（准一维或二维）和形态（针状或片状晶体）。最近，通过有意抑制固有各向异性生长，这类材料已被合成为纳米颗粒。X射线光电子能谱（XPS）已成为一种有价值的技术，用于表征电荷转移，因为它有能力区分高分辨率光谱中核心能级线化学位移所表现出的不同化学环境或电子构型。由于光发射过程本质上很快（远低于飞秒时间尺度），因此可以有效地探索动态过程。我们在此确定选定的基于TTF的导体纳米颗粒的光发射线上部分氧化的特征。
