ACS Applied Electronic Materials
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2020
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IF 0
Tianshu Zhai,Rongbin Wang,Takayoshi Katase,Frances Quigley,Hiromichi Ohta,Patrick Amsalem,Norbert Koch,Steffen Duhm
Tailor-made electrode work functions are indispensable to control energy-level offsets at the interfaces of (opto-)electronic devices. We show by means of photoelectron spectroscopy that several nanometer thick layers of the organic semiconductor 1,4,5,8,9,12-hexaazatriphenylene-2,3,6,7,10,11-hexacarbonitrile (HAT-CN) on virtually all substrates provide hole-injecting electrodes with work functions of around 5.60 eV. This substrate-independent energy-level alignment is due to a relatively large density of gap states in HAT-CN thin films, which is clearly visible in the photoemission data. Furthermore, this additional density of occupied states makes the wide-gap semiconductor thin films sufficiently conductive for electrode applications. Moreover, our study highlights a quite intriguing energy-level alignment scenario as the Fermi-level in HAT-CN thin films is located far from the midgap position, this is rather uncommon for undoped organic semiconductor thin films.
研究领域:
材料科学
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物理化学
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产品关联
DOI
RSC Advances
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2020
·Vol. 10
·期 30
·17653-17659
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IF 3.119
Dingyan Xu,Qun Wan,Siyao Wu,Yu Zhao,Xinglei Xu,Liang Li,Gufeng He
Lead halide perovskites have been considered promising materials for optoelectronic applications owing to their superior properties. CsPbBr3 nanocrystals (NCs) with a narrow particle size distribution and a narrow emission spectrum are synthesized by ligand-assisted re-precipitation (LARP), a low-cost and facile process. In inverted CsPbBr3 NC LEDs, a dual hole injection layer (HIL) of 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN)/MoO3 is introduced to enhance hole injection and transport, because HAT-CN can extract electrons easily from the hole transport layer and leave a large number of holes there. The current and power efficiencies of the optimized device with a dual HIL are 1.5- and 1.8-fold higher than those of the single HIL device. It is believed that the dual HAT-CN/MoO3 HIL effectively promotes hole injection and has promise for application in many other devices.
研究领域:
材料科学
·
光电技术
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DOI
高影响因子
Inorganic Chemistry Frontiers
·
2026
·
IF 6.2
Maxim V. Mikhailenko,Tatiana Yu. Astakhova,Elena N. Timokhina,Maxim A. Faraonov,Alexey V. Kuzmin,Salavat S. Khasanov,Denis V. Korchagin,Gennady V. Shilov,Akihiro Otsuka,Hiroshi Kitagawa,Dmitri V. Konarev
A series of anionic bi- and trinuclear complexes of CoII, FeII and MnII with hexaazatrinaphthylene (HATNA) and hexaazatriphenylenehexacarbonitrile (HAT(CN)6), incorporating paramagnetic Cp*2Fe+ cations (S = 1/2), were obtained. It was demonstrated that even a mild Cp*2Fe reductant can be used to reduce metal complexes of HAT-type ligands. Metal iodides were transferred from the pristine powder to the complexes in a non-coordinating solvent via complex formation with spiropyran or tetrabutylammonium iodide. The isostructural complexes (Cp*2Fe+)[(MIII2)2·HATNA]−·C6H4Cl2·0.5C6H14 (M = Co (1), Fe (2) and Mn (3)) contain monoanionic [(MIII2)2·HATNA]− units, which alternate in π-stacks with Cp*2Fe+ cations and also form π-stacked [(MIII2)2·HATNA−]2 dimers. Metal ion coordination is asymmetric, featuring one short and one long M–N bond. The short M–N bonds are 1.973(6) Å for CoII (1), 2.039(4) Å for FeII (2), and 2.115(4) Å for MnII (3); these are the shortest bonds reported to date among studied HAT-based complexes for CoII and FeII. These complexes exhibit very strong antiferromagnetic metal–radical coupling, which isolates their high-spin ground states at high temperatures. To the best of our knowledge, the exchange coupling value of −300 cm−1 observed for 3 is the highest among MnII-containing complexes based on a radical ligand with delocalized spin. Compound (Cp*2Fe+)[(FeIII2)3·HATNA]−·C6H4Cl2 (4) is unique due to its magnetic behavior, which is severely different from that previously observed for similar trinuclear radical FeII-containing HAT-based complexes. Instead of a smooth increase in the χMT value with a temperature decrease, attributed to the formation of a high-spin system, a rapid increase below 30 K is observed. Trinuclear trianionic species [(FeIII2)3·HAT(CN)6]3− are isolated in (Cp*2Fe+)3[(FeIII2)3·HAT(CN)6]3−·4C6H4Cl2 (5) and do not participate in intermolecular exchange coupling. The unusual magnetic behavior of 5 can only be described by a model implying different signs of D for metal ions in the complex. Such a feature arises from the substantial difference in the coordination geometry of one Fe1 ion compared to the other two Fe2 ions.
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DOI
高影响因子
Materials Horizons
·
2024
·
IF 12.2
Bo Peng,Pengbo Wang,Hang Luo,Guanghu He,Haoran Xie,Yuan Liu,Sheng Chen,Xiaona Li,Yuting Wan,Ru Guo
Improving the high-temperature performance of polymer dielectrics is critical for the development of advanced electrical systems. The deterioration of the capacitive performance of polymer dielectrics at high electric fields and elevated temperatures is attributable to the exponentially increased conduction loss. Herein, a synergistic strategy of molecular trap and aggregation structure optimization is developed to suppress the conduction loss of polymer dielectrics. A molecular semiconductor – HAT-CN with high electron-affinity (EA) and special distribution of electrostatic potential is designed in this work. The theoretical calculation and experimental results show that HAT-CN can introduce electron traps and simultaneously interrupt the conjugation between aromatic rings in molecular chains via electrostatic interaction with polyetherimide (PEI). Consequently, the collective effect of electron trap and aggregation structure optimization reduces the leakage current density of PEI by nearly an order of magnitude at 200 °C and improves the mechanical properties of films. Finally, the HAT-CN/PEI all-organic composite achieves a discharge energy density of 3.8 J cm−3 with efficiencies above 90% (Uη>90%) and long-term reliability over 100 000 cycles at 200 °C, outperforming most current polymer dielectrics. This work provides a new idea for the design of high-temperature polymer dielectrics based on molecularly engineered organic semiconductors.
研究领域:
材料科学
·
电气工程
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产品关联
DOI
PubMed
高影响因子
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