The Experts below are selected from a list of 18600 Experts worldwide ranked by ideXlab platform
Jihua Chen - One of the best experts on this subject based on the ideXlab platform.
-
polyferrocenylsilane semicrystalline Polymer Additive for solution processed p channel organic thin film transistors
Polymers, 2021Co-Authors: Ziyang Zhang, Kyeiwaa Asareyeboah, Jihua ChenAbstract:In this study, we demonstrated for the first time that a metal-containing semicrystalline Polymer was used as an Additive to mediate the thin film morphology of solution-grown, small-molecule organic semiconductors. By mixing polyferrocenylsilane (PFS) with an extensively-studied organic semiconductor 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene), PFS as a semicrystalline Polymer independently forms nucleation and crystallization while simultaneously ameliorating diffusivity of the blend system and tuning the surface energies as a result of its partially amorphous property. We discovered that the resultant blend film exhibited a 6-fold reduction in crystal misorientation angle and a 3-fold enlargement in average grain width. Enhanced crystal orientation considerably reduces mobility variation, while minimized defects and trap centers located at grain boundaries lessen the adverse impact on the charge transport. Consequently, bottom-gate, top-contact organic thin film transistors (OTFTs) based on the TIPS pentacene/PFS mixture yielded a 40% increase in performance consistency (represented by the ratio of average mobility to the standard deviation of mobility). The PFS semicrystalline Polymer-controlled crystallization can be used to regulate the thin film morphology of other high-performance organic semiconductors and shed light on applications in organic electronic devices.
-
conjugated Polymer controlled morphology and charge transport of small molecule organic semiconductors
Scientific Reports, 2020Co-Authors: Ziyang Zhang, Jihua ChenAbstract:In this study, we report an effective approach to tune the crystallization, microstructure and charge transport of solution-processed organic semiconductors by blending with a conjugated Polymer Additive poly(3-hexylthiophene) (P3HT). When 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) was used as a model semiconductor material to mix with different amount of P3HT, their intermolecular interactions led to distinctive TIPS pentacene film morphologies, including randomly-oriented crystal ribbons, elongated needles with enhanced long-range order, and grass-like curved microwires with interlinkages. Each type of morphology was found to further correlate to considerably different charge transport and device performance. As compared to pristine TIPS pentacene devices, bottom-gate, top-contact OTFTs with 2% in weight P3HT Additive showed a 2-fold and 5-fold improvement of average field-effect mobility and performance consistency (defined as the ratio of average mobility to the standard deviation), respectively. The improvement in transistor electrical performance can be attributed to the combined effect of enhanced crystal orientation and uniformity, as well as increased areal coverage. This work can be applied beyond the particular example demonstrated in this study and to tune the charge transport of other small-molecule organic semiconductors in general.
-
Polymer Additive controlled morphology for high performance organic thin film transistors
Soft Matter, 2019Co-Authors: Jihua ChenAbstract:Solution-crystallizable small-molecule organic semiconductors, such as 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS pentacene), 5,11-bis(triethylgermylethynyl)anthradithiophene (diF-TEG-ADT), 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT), and N,N′-1H,1H-perfluorobutyl dicyanoperylenecarboxydiimide (PDIF-CN2), demonstrate various practical advantages including high mobility, air stability and solution processibility. In this article, we review various Polymer Additive based approaches to control the crystal morphology and the resultant charge transport of some bench-mark, high performance, solution crystallizable, small-molecule organic semiconductors. The Polymer Additives are discussed under the categories of non-conjugated Polymers and conjugated Polymers. The approaches and structure-performance correlations that we discussed here may be applied far beyond the examples shown in this review and have important implications for high performance organic semiconductors in general.
Ziyang Zhang - One of the best experts on this subject based on the ideXlab platform.
-
polyferrocenylsilane semicrystalline Polymer Additive for solution processed p channel organic thin film transistors
Polymers, 2021Co-Authors: Ziyang Zhang, Kyeiwaa Asareyeboah, Jihua ChenAbstract:In this study, we demonstrated for the first time that a metal-containing semicrystalline Polymer was used as an Additive to mediate the thin film morphology of solution-grown, small-molecule organic semiconductors. By mixing polyferrocenylsilane (PFS) with an extensively-studied organic semiconductor 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene), PFS as a semicrystalline Polymer independently forms nucleation and crystallization while simultaneously ameliorating diffusivity of the blend system and tuning the surface energies as a result of its partially amorphous property. We discovered that the resultant blend film exhibited a 6-fold reduction in crystal misorientation angle and a 3-fold enlargement in average grain width. Enhanced crystal orientation considerably reduces mobility variation, while minimized defects and trap centers located at grain boundaries lessen the adverse impact on the charge transport. Consequently, bottom-gate, top-contact organic thin film transistors (OTFTs) based on the TIPS pentacene/PFS mixture yielded a 40% increase in performance consistency (represented by the ratio of average mobility to the standard deviation of mobility). The PFS semicrystalline Polymer-controlled crystallization can be used to regulate the thin film morphology of other high-performance organic semiconductors and shed light on applications in organic electronic devices.
-
conjugated Polymer controlled morphology and charge transport of small molecule organic semiconductors
Scientific Reports, 2020Co-Authors: Ziyang Zhang, Jihua ChenAbstract:In this study, we report an effective approach to tune the crystallization, microstructure and charge transport of solution-processed organic semiconductors by blending with a conjugated Polymer Additive poly(3-hexylthiophene) (P3HT). When 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) was used as a model semiconductor material to mix with different amount of P3HT, their intermolecular interactions led to distinctive TIPS pentacene film morphologies, including randomly-oriented crystal ribbons, elongated needles with enhanced long-range order, and grass-like curved microwires with interlinkages. Each type of morphology was found to further correlate to considerably different charge transport and device performance. As compared to pristine TIPS pentacene devices, bottom-gate, top-contact OTFTs with 2% in weight P3HT Additive showed a 2-fold and 5-fold improvement of average field-effect mobility and performance consistency (defined as the ratio of average mobility to the standard deviation), respectively. The improvement in transistor electrical performance can be attributed to the combined effect of enhanced crystal orientation and uniformity, as well as increased areal coverage. This work can be applied beyond the particular example demonstrated in this study and to tune the charge transport of other small-molecule organic semiconductors in general.
-
phase segregation effect on tips pentacene crystallization and morphology for organic thin film transistors
Journal of Materials Science: Materials in Electronics, 2020Co-Authors: Kyeiwaa Asareyeboah, Ziyang ZhangAbstract:In this study, we report that the vertical phase separation between a small-molecule organic semiconductor and a Polymer Additive can be utilized to drive semiconductor crystallization, enhance thin film morphology, and improve device performance of solution-processed organic thin film transistors (OTFTs). When 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) was demonstrated as a benchmark semiconductor material to blend with a polyacrylate Polymer Additive poly(2-ethylhexyl acrylate) (P2EHA), it was found that a vertical phase segregation occurred between TIPS pentacene and P2EHA, providing a confinement of anisotropic semiconductor crystallization and resulting in an elevated TIPS pentacene concentration at the charge transport interface. Accordingly, distinctive TIPS pentacene thin film morphology in terms of areal coverage, grain width, and crystal orientation was obtained by varying the loading ratio of the P2EHA Polymer Additive. Bottom-gate and bottom-contact OTFTs were fabricated to test charge transport and a hole mobility of up to 0.27 cm2/Vs was demonstrated with 80% loading ratio of P2EHA. The effective experimental method and important results as we showcased in this work can be applied to drive crystallization and optimize film morphology of small-molecule organic semiconductors other than TIPS pentacene.
-
polyacrylate Polymer assisted crystallization improved charge transport and performance consistency for solution processable small molecule semiconductor based organic thin film transistors
Journal of Science: Advanced Materials and Devices, 2019Co-Authors: Zhengran He, Ziyang Zhang, Sheng BiAbstract:Abstract In this study, we report on an effective approach to modulate crystallization, control charge transport and enhance performance consistency of small-molecule semiconductor based organic thin film transistors (OTFTs) with the addition of a polyacrylate Polymer Additive poly(2-ethylhexyl acrylate) (P2EHA). 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) was used as a benchmark semiconductor to blend with the P2EHA Additive, leading to a vertical phase separation between these two components. The resultant TIPS pentacene film exhibited greatly reduced crystal misorientation, enlarged grain width and enhanced film coverage. Bottom-gate, bottom-contact OTFTs based on the TIPS pentacene/P2EHA blends were fabricated and showed an increased average hole mobility of 0.317 ± 0.047 cm2/V, as well as a performance consistency factor of 6.72, which is defined as the ratio of the average hole mobility to the standard deviation of mobility. Notably, it leads to a 10-fold and 7-fold enhancement of average mobility and performance consistency as compared to the pristine TIPS pentacene OTFTs. This great improvement of device performance can be attributed to the reduced crystal misorientation, less defects and trap centers at the grain boundaries as a result of the enlarged grain width, as well as increased film coverage, due to the addition of the P2EHA polyacrylate Polymer Additive.
Joshua W. R. Baur - One of the best experts on this subject based on the ideXlab platform.
-
Process-structure-property effects on ABS bond strength in fused filament fabrication
Additive Manufacturing, 2018Co-Authors: A.c. Abbott, R.l. Bradford, Gyaneshwar P. Tandon, Hilmar Koerner, Joshua W. R. BaurAbstract:Interlayer bonds pose regions of weakness in structures produced via melt extrusion based Polymer Additive manufacturing. Bond strength was assessed both between layers and within layers as a function of print parameters by performing tensile tests on ABS coupons printed in two orientations. Print parameters considered were extruder temperature, print speed, and layer height. An IR camera was used to track thermal history of interlayer bond lines during the printing process. Contact length between roads was measured from mesostructure optical micrographs. Print speed was found to have a large impact on tensile strength with high speeds generally yielding lower strength. A plateau in tensile strength of 22 MPa was observed for a normalized contact length greater than 0.6 independent of print orientation.
Ankur Jain - One of the best experts on this subject based on the ideXlab platform.
-
improvement in build direction thermal conductivity in extrusion based Polymer Additive manufacturing through thermal annealing
Additive manufacturing, 2019Co-Authors: Hardikkumar Prajapati, Divya Chalise, Darshan Ravoori, Robert M Taylor, Ankur JainAbstract:Abstract While Additive manufacturing offers significant advantages compared to traditional manufacturing technologies, deterioration in thermal and mechanical properties compared to properties of the underlying materials is a serious concern. In the context of Polymer extrusion based Additive manufacturing, post-process approaches, such as thermal annealing have been reported for improving mechanical properties based on reptation of Polymer chains and enhanced filament-to-filament adhesion. However, there is a lack of similar work for improving thermal properties such as thermal conductivity. This paper reports significant enhancement in build-direction thermal conductivity of Polymer extrusion based parts as a result of thermal annealing. Over 150% improvement is observed when annealed at 135 °C for 96 h. The effect of annealing temperature and time on thermal conductivity enhancement is investigated through experiments. A theoretical model based on Arrhenius kinetics for neck growth and a heat transfer model for the consequent impact on inter-layer thermal contact resistance is developed. Predicted thermal conductivity enhancement is found to be in good agreement with experimental data for a wide range of annealing temperature and time. The theoretical model may play a key role in developing practical thermal annealing strategies that account for the multiple constraints involved in annealing of Polymer parts. This work may facilitate the use of Polymer extrusion Additive manufacturing for producing enhanced thermal conductivity parts capable of withstanding thermal loads.
Wai Yee Yeong - One of the best experts on this subject based on the ideXlab platform.
-
process structure properties in Polymer Additive manufacturing via material extrusion a review
Critical Reviews in Solid State and Materials Sciences, 2020Co-Authors: Guo Dong Goh, Yee Ling Yap, Heang Kuan Joel Tan, Swee Leong Sing, Guo Liang Goh, Wai Yee YeongAbstract:This article provides a database of the mechanical properties of Additively manufactured Polymeric materials fabricated using material extrusion (e.g., fused filament fabrication (FFF)). Mechanical...