Photoemission Study of Charge Transfer between ET (BEDT-TTF) and Acceptors F6TCNNQ and F2TCNQ
Photoemission Study of Charge Transfer between ET (BEDT-TTF) and Acceptors F6TCNNQ and F2TCNQ
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DOI：
10.1021/acs.jpcc.1c05573
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发表时间：
2021-08-19
影响因子：
3.7
通讯作者：
Knupfer，Martin
中科院分区：
文献类型：
--
作者：
Kuhrt，Robert;Hantusch，Martin;Knupfer，Martin
有机半导体的电子性质可以通过电荷转移到电子接受分子来改变。本文采用光电子能谱研究了BEDT-TTF（ET）与两种分子受体F2 TCNQ和F6 TCNNQ之间的电荷转移反应。材料在真空条件下蒸发在彼此的顶部上，并且在每个沉积步骤之后探测芯能级以及价轨道的变化。核心水平的光谱显示电荷转移的两个接口，这是更高的ET/F6 TCNNQ接口根据不同的强度比，以及不同的BE位移的中性和阳离子光谱。硫原子对ET的HOMO的不相等贡献转化为对氧化ET的S 2 p芯能级谱的额外贡献。化合物的价态光谱表明受体的LUMO被占据。两个界面都没有显示出在费米能级上占据态密度的迹象。功函数的进展表明，ET和F6 TCNNQ形成相对尖锐的接口，而观察到的迹象，相互扩散的ET/F2 TCNQ组合。
The electronic properties of organic semiconductors can be modified by a charge transfer to electron accepting molecules. In this study, the charge transfer reactions between BEDT-TTF (ET) and the two molecular acceptors F2TCNQ and F6TCNNQ were investigated by photoemission spectroscopy. The materials were evaporated under vacuum conditions on top of each other, and changes in the core levels as well as the valence orbitals were probed after each deposition step. The core level spectra showed charge transfer for both interfaces, which was higher for the ET/F6TCNNQ interface according to different intensity ratios as well as different BE shifts of neutral and cationic spectra. The unequal contribution of the sulfur atoms to the HOMO of ET translated to an additional contribution to the S 2p core level spectra of oxidized ET. The valence spectra showed the occupation of the acceptor’s LUMO. Both interfaces did not show signs of occupied density of states at the Fermi level. The progression of the work function suggested that ET and F6TCNNQ form relatively sharp interfaces while signs for interdiffusion were observed for the ET/F2TCNQ combination.