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391 results on '"Mei, Jianguo"'

113. Analysis of the Fabrication Conditions in Organic Field-Effect Transistors

Author

Rahn, Rachel M, Zhao, Yan, and Mei, Jianguo

Subjects
Optimization, Fabrication, Organic Chemistry, Materials Chemistry, OFET, Organic Field-Effect Transistor, Charge Carrier Mobility, Processing, Chemical Engineering, Polymer Chemistry
Abstract

Polymer-based organic field-effect transistors have raised substantial awareness because they enable low-cost, solution processing techniques, and have the potential to be implemented in flexible, disposable organic electronic devices. The performance of these devices is highly dependent on the processing conditions, as well as the intrinsic properties of the polymer. Processing conditions play an important role in semiconductor film formation and device performance. These factors may provide an important link between structure and performance. In this study, an empirical analysis tool, Process Scout, was applied to assess processing factors such as polymer concentration and silicon modification. This sanctioned the creation of a realistic optimization model because common variance was not assumed and the mobility was capably analyzed in the real space. After the analysis of the processing conditions, it was evident that further study on the effect of humidity on performance must be conducted to account for the variance between similarly fabricated devices. The developed process may be applied to expand the study of other organic semiconductors. This process is the first step in creating a standard fabrication protocol, allowing organic field-effect transistors to prosper.

Published
2015

115. Synthesis and Characterization of n-Doped Poly(benzodifurandione) (n-PBDF) Derivatives via Aromatic Substitution

Author

Ahmed, Mustafa H., Hwang, Jinhyo, Xiao, Bufan, Schiavone, Matthew R., Chaudhary, Jagrity, Chen, Min, and Mei, Jianguo

Abstract

n-Doped poly(benzodifurandione) (n-PBDF) is an n-type conducting polymer with characteristics such as high electrical conductivity, solution processability, and weathering stability. Here, we systematically investigate the structure property relationship on the impact of structural modifications through aromatic substitution on the photophysical, electrical, and structural properties of n-PBDFand its oligomeric derivatives. We demonstrated that an electron donation group (methyl) raised the highest occupied molecular orbital energy level (+0.15 eV), while electron-withdrawing halogens (Br and Cl) decreased the lowest unoccupied molecular orbital energy level (−0.12 and −0.13 eV, respectively) in the polymers. Additionally, in both the undoped and doped oligomeric systems, these substitutions introduce large torsion angles (θ > 17°), causing the material to twist significantly. Moreover, the methyl-substituted polymer, n-PBDF-Me, was evaluated for its potential as a transparent organic conductor, due to its high optical transmittance (T550> 93%). However, n-PBDF-Mefilms have significantly lower conductivity than n-PBDF(0.40 vs 1330 S/cm) at similar thickness.

Published
2024
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116. Understanding Interfacial Alignment in Solution Coated Conjugated Polymer Thin Films

Author

Qu, Ge, Zhao, Xikang, Newbloom, Gregory M., Zhang, Fengjiao, Mohammadi, Erfan, Strzalka, Joseph W., Pozzo, Lilo D., Mei, Jianguo, and Diao, Ying

Abstract

Domain alignment in conjugated polymer thin films can significantly enhance charge carrier mobility. However, the alignment mechanism during meniscus-guided solution coating remains unclear. Furthermore, interfacial alignment has been rarely studied despite its direct relevance and critical importance to charge transport. In this study, we uncover a significantly higher degree of alignment at the top interface of solution coated thin films, using a donor–acceptor conjugated polymer, poly(diketopyrrolopyrrole-co-thiophene-co-thieno[3,2-b]thiophene-co-thiophene) (DPP2T-TT), as the model system. At the molecular level, we observe in-plane π–π stacking anisotropy of up to 4.8 near the top interface with the polymer backbone aligned parallel to the coating direction. The bulk of the film is only weakly aligned with the backbone oriented transverse to coating. At the mesoscale, we observe a well-defined fibril-like morphology at the top interface with the fibril long axis pointing toward the coating direction. Significantly smaller fibrils with poor orientational order are found on the bottom interface, weakly aligned orthogonal to the fibrils on the top interface. The high degree of alignment at the top interface leads to a charge transport anisotropy of up to 5.4 compared to an anisotropy close to 1 on the bottom interface. We attribute the formation of distinct interfacial morphology to the skin-layer formation associated with high Peclet number, which promotes crystallization on the top interface while suppressing it in the bulk. We further infer that the interfacial fibril alignment is driven by the extensional flow on the top interface arisen from increasing solvent evaporation rate closer to the meniscus front.

Published
2024
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117. Complementary Semiconducting Polymer Blends: Influence of Side Chains of Matrix Polymers

Author

Zhao, Xikang, Xue, Guobiao, Qu, Ge, Singhania, Vani, Zhao, Yan, Butrouna, Kamal, Gumyusenge, Aristide, Diao, Ying, Graham, Kenneth R., Li, Hanying, and Mei, Jianguo

Abstract

The concept of complementary semiconducting polymer blends (c-SPBs) has been recently proposed to achieve enhanced solution processability and/or melt-processing capability for organic electronics. In the previous study, we demonstrated the impact of conjugation-break spacers of matrix polymers. In the current work, we explore the influence of the side chains of the matrix polymer on the physical properties of the pure polymers and their corresponding c-SPBs, including electrical properties and phase transition behaviors. Six diketopyrrolopyrrole (DPP)-based polymers with pentamethylene conjugation-break spacers (CBSs) and various side chains, including branched-alkyl, triethylene glycol (TEG), and siloxane-terminated side chains, were synthesized and characterized. The UV–vis spectra show that the side chains have a noticeable impact on the intermolecular interactions in the solid states. In addition, side chains also have a significant influence on the thermal behaviors of the polymers. Polymers with asymmetric side chains attached to the same DPP unit exhibit lower melting points compared to the congeners with symmetric side chains. The polymer with both branched-alkyl and TEG side chain exhibits the lowest melting point of 104 °C. As for charge transport properties, polymers with branched-alkyl and/or siloxane-terminated side chains give hole mobilities on the same order of magnitude, whereas the polymers with TEG side chains exhibits much lower mobilities. When c-SPBs with a fully conjugated polymer with branched-alkyl side chains are concerned, the c-SPBs of all polymers, except for the polymer with only TEG side chains (TEG-DPP-C5), show hole mobilities 2 orders of magnitude higher than the corresponding pure matrix polymers. In contrast, TEG-DPP-C5 merely presents an improvement of 20 times, which resulted from the incompatibility of TEG side chains from the matrix polymer and the alkyl side chains from the tie chain polymer. These results provide new insights into structural design for semiconducting materials with both high performance and better processability.

Published
2024
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119. Polymer Semiconductors: Combinatorial Study of Temperature‐Dependent Nanostructure and Electrical Conduction of Polymer Semiconductors: Even Bimodal Orientation Can Enhance 3D Charge Transport (Adv. Funct. Mater. 26/2016)

Author

Park, Sangsik, primary, Lee, Moo Hyung, additional, Ahn, Kwang Seok, additional, Choi, Hyun Ho, additional, Shin, Jihye, additional, Xu, Jie, additional, Mei, Jianguo, additional, Cho, Kilwon, additional, Bao, Zhenan, additional, Lee, Dong Ryeol, additional, Kang, Moon Sung, additional, and Kim, Do Hwan, additional

Published
2016
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120. Combinatorial Study of Temperature‐Dependent Nanostructure and Electrical Conduction of Polymer Semiconductors: Even Bimodal Orientation Can Enhance 3D Charge Transport

Author

Park, Sangsik, primary, Lee, Moo Hyung, additional, Ahn, Kwang Seok, additional, Choi, Hyun Ho, additional, Shin, Jihye, additional, Xu, Jie, additional, Mei, Jianguo, additional, Cho, Kilwon, additional, Bao, Zhenan, additional, Lee, Dong Ryeol, additional, Kang, Moon Sung, additional, and Kim, Do Hwan, additional

Published
2016
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122. Hierarchical N-Doped Carbon as CO2 Adsorbent with High CO2 Selectivity from Rationally Designed Polypyrrole Precursor

Author

To, John W. F., primary, He, Jiajun, additional, Mei, Jianguo, additional, Haghpanah, Reza, additional, Chen, Zheng, additional, Kurosawa, Tadanori, additional, Chen, Shucheng, additional, Bae, Won-Gyu, additional, Pan, Lijia, additional, Tok, Jeffrey B.-H., additional, Wilcox, Jennifer, additional, and Bao, Zhenan, additional

Published
2016
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125. Significance of the double-layer capacitor effect in polar rubbery dielectrics and exceptionally stable low-voltage high transconductance organic transistors

Author

Wang, Chao, Lee, Wen-Ya, Kong, Desheng, Pfattner, Raphael, Schweicher, Guillaume, Nakajima, Reina, Lu, Chien, Mei, Jianguo, Lee, Tae Hoon, Wu, Hung-Chin, Lopez, Jeffrey, Diao, Ying, Gu, Xiaodan, Himmelberger, Scott, Niu, Weijun, Matthews, James R., He, Mingqian, Salleo, Alberto, Nishi, Yoshio, Bao, Zhenan, Wang, Chao, Lee, Wen-Ya, Kong, Desheng, Pfattner, Raphael, Schweicher, Guillaume, Nakajima, Reina, Lu, Chien, Mei, Jianguo, Lee, Tae Hoon, Wu, Hung-Chin, Lopez, Jeffrey, Diao, Ying, Gu, Xiaodan, Himmelberger, Scott, Niu, Weijun, Matthews, James R., He, Mingqian, Salleo, Alberto, Nishi, Yoshio, and Bao, Zhenan

Abstract

Both high gain and transconductance at low operating voltages are essential for practical applications of organic field-effect transistors (OFETs). Here, we describe the significance of the double-layer capacitance effect in polar rubbery dielectrics, even when present in a very low ion concentration and conductivity. We observed that this effect can greatly enhance the OFET transconductance when driven at low voltages. Specifically, when the polar elastomer poly(vinylidene fluoride-co-hexafluoropropylene) (e-PVDF-HFP) was used as the dielectric layer, despite a thickness of several micrometers, we obtained a transconductance per channel width 30 times higher than that measured for the same organic semiconductors fabricated on a semicrystalline PVDF-HFP with a similar thickness. After a series of detailed experimental investigations, we attribute the above observation to the double-layer capacitance effect, even though the ionic conductivity is as low as 10–10 S/cm. Different from previously reported OFETs with double-layer capacitance effects, our devices showed unprecedented high bias-stress stability in air and even in water., info:eu-repo/semantics/published

Published
2015

126. Significance of the double-layer capacitor effect in polar rubbery dielectrics and exceptionally stable low-voltage high transconductance organic transistors

Author

Wang, Chao, primary, Lee, Wen-Ya, additional, Kong, Desheng, additional, Pfattner, Raphael, additional, Schweicher, Guillaume, additional, Nakajima, Reina, additional, Lu, Chien, additional, Mei, Jianguo, additional, Lee, Tae Hoon, additional, Wu, Hung-Chin, additional, Lopez, Jeffery, additional, Diao, Ying, additional, Gu, Xiaodan, additional, Himmelberger, Scott, additional, Niu, Weijun, additional, Matthews, James R., additional, He, Mingqian, additional, Salleo, Alberto, additional, Nishi, Yoshio, additional, and Bao, Zhenan, additional

Published
2015
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127. Continuous Melt‐Drawing of Highly Aligned Flexible and Stretchable Semiconducting Microfibers for Organic Electronics.

Author

Zhao, Yan, Gumyusenge, Aristide, He, Jiazhi, Qu, Ge, McNutt, William W., Long, Yuan, Zhang, Hongyi, Huang, Libai, Diao, Ying, and Mei, Jianguo

Subjects
SEMICONDUCTORS, ORGANIC electronics, MICROFIBERS, ORGANIC conductors, FIELD-effect transistors
Abstract

Abstract: A scalable and green approach to manufacture semiconducting microfibers from polymer melts has been demonstrated. The polymer chains are highly aligned along the microfiber's long axis direction and exhibit highly anisotropic optical properties. In addition, the polymer microfibers show good flexibility and stretchability with a yield point around 10% under a reversible stress and can be stretched up to 180% without breaking. These features are desired for future flexible, stretchable, and conformable electronics. The origin of this stretchability is studied with diketopyrrolopyrrole derivatives using different conjugation break spacers and side chains. In addition, stretchable conducting microfibers can be obtained by doping with FeCl3, which are further evaluated as organic conductors and source/drain electrodes in organic field‐effect transistors. [ABSTRACT FROM AUTHOR]

Published
2018
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128. Zone‐Annealing‐Assisted Solvent‐Free Processing of Complementary Semiconducting Polymer Blends for Organic Field‐Effect Transistors.

Author

Xue, Guobiao, Zhao, Yan, Zhao, Xikang, Li, Hanying, and Mei, Jianguo

Subjects
ANNEALING of metals, SEMICONDUCTOR films, ELECTRIC properties of polymers, ORGANIC field-effect transistors, PRINTED electronics
Abstract

Abstract: Semiconducting polymer thin films, which are usually formed by solution‐casting from their organic solutions, are critical in the development of flexible and printed electronics. To seek out a method that can further improve the electrical properties of semiconducting polymers and also be industrially applicable is of vital significance. In this study, the impact of zone annealing on the charge‐transport properties of diketopyrrolopyrrole‐based complementary semiconducting polymer blends in field‐effect transistor devices is investigated. An average mobility increased from 0.66 to 0.87 cm2 V−1 s−1, with a highest of 1.6 cm2 V−1 s−1, is observed. It is also demonstrated that zone annealing can be integrated with melt processing to realize a solvent‐free process for polymer thin films for organic field‐effect transistors (OFETs) and achieve improved charge transport characteristics with a record mobility of 0.54 cm2 V−1 s−1 among melt‐processed OFETs. This work provides an alternative, green, and sustainable processing method to advance polymer‐based organic electronics. [ABSTRACT FROM AUTHOR]

Published
2018
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137. High Performance All‐Polymer Solar Cell via Polymer Side‐Chain Engineering

Author

Zhou, Yan, primary, Kurosawa, Tadanori, additional, Ma, Wei, additional, Guo, Yikun, additional, Fang, Lei, additional, Vandewal, Koen, additional, Diao, Ying, additional, Wang, Chenggong, additional, Yan, Qifan, additional, Reinspach, Julia, additional, Mei, Jianguo, additional, Appleton, Anthony Lucas, additional, Koleilat, Ghada I., additional, Gao, Yongli, additional, Mannsfeld, Stefan C. B., additional, Salleo, Alberto, additional, Ade, Harald, additional, Zhao, Dahui, additional, and Bao, Zhenan, additional

Published
2014
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146. Scalable and Selective Dispersion of Semiconducting Arc-Discharged Carbon Nanotubes by Dithiafulvalene/Thiophene Copolymers for Thin Film Transistors

Author

Wang, Huiliang, primary, Mei, Jianguo, additional, Liu, Peng, additional, Schmidt, Kristin, additional, Jiménez-Osés, Gonzalo, additional, Osuna, Sílvia, additional, Fang, Lei, additional, Tassone, Christopher J., additional, Zoombelt, Arjan Pieter, additional, Sokolov, Anatoliy N., additional, Houk, Kendall N., additional, Toney, Michael F., additional, and Bao, Zhenan, additional

Published
2013
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