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- Hu, Yuanyuan, et al.
(author)
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Correlation of Molecular Structure and Charge Transport Properties: A Case Study in Naphthalenediimide–Based Copolymer Semiconductors
- 2018
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In: Advanced Electronic Materials. - : Wiley. - 2199-160X .- 2199-160X. ; 4:8
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Journal article (peer-reviewed)abstract
- Recent development of donor–acceptor (D–A) structure copolymers has led to the remarkable enhancement of mobility over 10 cm2(V s)−1in organic semiconductors. Despite these achievements, a thorough understanding of the correlation between molecular structure and charge transport properties is still not achieved. With this goal in mind, the electrical properties of three copolymers based on the naphthalenediimide (NDI) acceptor with different donor units are compared, and the effect of increasing donor length on the electronic structure of semiconductors and the resulting charge transport performance is studied. Structural and morphological characterizations are done to reveal the macro transport properties of the semiconductor films. Then, electrical measurements of the field-effect transistors at variable temperatures are carried out to probe the charge transport property of the semiconductor films. Overall, it is found that the increasing of the donor length from one to three thiophene units would reduce the energetic disorder in the semiconductor films. Meanwhile, the electron cloud overlap between acceptor units would be weakened, which is detrimental to electron transport. Thus, a trading-off between energetic disorder and electron cloud overlap is critical for achieving high mobility in this NDI–based copolymer system.
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| 2. |
- Wang, Lei, 1989-
(author)
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Protein Nanomaterials: : Functionalization, Self-assembly, and Applications
- 2020
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Doctoral thesis (other academic/artistic)abstract
- As one of the major classes of materials that is relevant to biological function of our daily life, proteins are highly interesting in both biological and material science. Self-assembled protein amyloid nanostructures have been considered not only as aggregates in pathological tissue, but also as a kind of advanced one dimension materials in material science perspective due to their favorable characteristics including high aspect ratio, abundant surface charge groups, high stability, and tunable surface properties. The Protein nanofibrils (PNFs) can be self-assembly derived from a wide range of proteins, which isolated from natural and renewable sources, means it is relative cheap, environmentally friendly, and sustainable. The PNFs will contain additional functionalized properties for further applications by functionalizing with other materials such as fluorophores or conducting materials. An easy method is to utilize mechanochemistry, such as the use of a shaker mixer mill for grinding operation as well as hand grinding by mortar and pestle, helping mixing materials into fine powder thus helping the insoluble compounds and protein mixture to be water dispersible. Also, the liquid assisting ball milling exfoliation was achieved by high impact force to fracture the graphite and shear force to exfoliate the layered structure. In this thesis, interesting new properties of protein hybrids have been studied mainly focusing on two aspects: 1) by co-grinding hydrophobic dyes and proteins, a protein hydrophobic compound hybrid is obtained and following by inducing fibrils formation. The resulting functionalized PNFs thus have the fibril structure properties as well as the properties from incorporated compounds. By further self-assembly the functionalized PNFs to films, the materials transfer from micro to macrostructure. Besides, the protein act as surfactant for disperse hydrophobic probes for detection of Cu2+. 2) by milling the protein or protein nanofibrils dispersion with graphite, Graphene nanoplatelets (GNPs) is exfoliated and the GNPs ink functionalized by PNFs converted to devices and shows good properties for thermoelectrical voltage generation and water evaporation induced energy generation. Throughout the study of the thesis, we summarize how the protein hybrid materials was investigated. By demonstrating dyes functionalized PNFs and further PNFs films, as well as GNPs-PNFs hybrids acting as active materials on thermoelectrical and evaporation induced energy generating devices, we show the protein hybrid materials a promise new breakthrough in optical or energy generating aspects.
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