Bar-coated high-performance organic thin-film transistors based on ultrathin PDFDT polymer with molecular weight independence

Nketia‐Yawson, Benjamin; Lee, Hyo-Sang; Son, Hae Jung; Kim, BongSoo; Noh, Yong‐Young

doi:10.1016/j.orgel.2015.11.033

Cited by 16 publications

(12 citation statements)

References 24 publications

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“…In addition, compared with blade shearing method, the solutions under the bars are usually less confined near the contact line and the effects induced by the blade edge can be minimized . The bar‐coating method has been widely applied to deposit polymers and polymer/small molecule blends; however, because of very fast shearing speeds and polymer‐chain entanglement, the deposited films are typically polycrystalline without preferential orientations, and grain size are limited to a few hundreds of µm . Using bars to grow small molecule crystals with controlled orientations is stills remains to be investigated.…”

Section: Introductionmentioning

confidence: 99%

Marangoni‐Effect‐Assisted Bar‐Coating Method for High‐Quality Organic Crystals with Compressive and Tensile Strains

Zhang

Peng

et al. 2017

Adv Funct Materials

143

148

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Low-cost solution-shearing methods are highly desirable for deposition of organic semiconductor crystals over a large area. To enhance the rate of evaporation and deposition, elevated substrate temperature is commonly employed during shearing processes. However, the Marangoni flow induced by a temperature-dependent surface-tension gradient near the meniscus line shows negative effects on the deposited crystals and its electrical properties. In the current study, the Marangoni effect to improve the shearing process of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene for organic field-effect transistor (OFET) applications is utilized and regulated. By modifying the gradient of surface tension with different combinations of solvents, the mass transport of molecules is much more favorable, which largely enhances the deposition rate, reduces organic crystal thickness, enlarges grain sizes, and improves coverage. The average and highest mobility of OFETs can be increased up to 13.7 and 16 cm 2 V −1 s −1 . This method provides a simple deposition approach on a large scale, which allows to further fabricate large-area circuits, flexible displays, or bioimplantable sensors.

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Section: Introductionmentioning

confidence: 99%

Marangoni‐Effect‐Assisted Bar‐Coating Method for High‐Quality Organic Crystals with Compressive and Tensile Strains

Zhang

Peng

et al. 2017

Adv Funct Materials

143

148

View full text Add to dashboard Cite

show abstract

“…Therefore, the fabrication of large-area organic electronic devices should rely on simple approaches, that is, the solution-based deposition of the organic semiconductors should be carried out in ambient conditions with high speed and throughput. The bar-coating method is an excellent candidate for active layer deposition over large areas because of its controllability, simplicity, and compatibility to the roll-to-roll process for flexible and large-area electronics. − …”

Section: Introductionmentioning

confidence: 99%

Bar-Coated Ultrathin Semiconductors from Polymer Blend for One-Step Organic Field-Effect Transistors

Ge¹,

Liu²,

Lee

et al. 2018

ACS Appl. Mater. Interfaces

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One-step deposition of bi-functional semiconductor-dielectric layers for organic field-effect transistors (OFETs) is an effective way to simplify the device fabrication. However, the proposed method has rarely been reported in large-area flexible organic electronics. Herein, we demonstrate wafer-scale OFETs by bar coating the semiconducting and insulating polymer blend solution in one-step. The semiconducting polymer poly(3-hexylthiophene) (P3HT) segregates on top of the blend film, whereas dielectric polymethyl methacrylate (PMMA) acts as the bottom layer, which is achieved by a vertical phase separation structure. The morphology of blend film can be controlled by varying the concentration of P3HT and PMMA solutions. The wafer-scale one-step OFETs, with a continuous ultrathin P3HT film of 2.7 nm, exhibit high electrical reproducibility and uniformity. The one-step OFETs extend to substrate-free arrays that can be attached everywhere on varying substrates. In addition, because of the well-ordered molecular arrangement, the moderate charge transport pathway is formed, which resulted in stable OFETs under various organic solvent vapors and lights of different wavelengths. The results demonstrate that the one-step OFETs have promising potential in the field of large-area organic wearable electronics.

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“…Additionally, bar‐coated films generally exhibit a highly uniform thickness because undesirable fluidic behaviors (e.g., coffee stain effects) are not involved in the bar‐coating process. Nketia‐Yawson et al reported on bar‐coated ultrathin polymer semiconducting films and constructed high‐performance OFETs . Ultrathin crystalline difluorobenzothiadiazole–dithienosilole (PDFDT) copolymer films were produced on a glass substrate by using the wire‐bar coating method.…”

Section: Solution‐based Techniques For Preparing 2dmcsmentioning

confidence: 99%

Solution‐Processed 2D Molecular Crystals: Fabrication Techniques, Transistor Applications, and Physics

Qian

Jiang

et al. 2018

Adv Materials Technologies

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the complex microstructures and undesir able qualities of conventional organic bulk thin films can largely lead to severe performance bottlenecks in functional OFETs [23,24] and serve as essential chal lenges in unveiling the intrinsic electrical properties. [25] Therefore, a new organic material is profoundly required to satisfy the anticipated demand for fundamental studies and to sustain the revolutionary advancement in organic electronics.As an emerging electronic material, 2D molecular crystals (2DMCs) have attracted particular attention since their discovery. [26,27] The material structure of 2DMC features a monolayer (ML) or few layers of molecules that are assembled via weak van der Waals (vDW) bonding along two dimensions. 2DMCs have also dem onstrated unique characteristics of thick ness uniformity over a large scale, perfect lateral continuity with an atomically flat surface, and longrange molecular ordering. Particularly, when the available conforma tions of crystalline molecular semiconductors are restricted under a special constraint geometry, the interlayer screening that commonly exists in the 3D bulk organic semiconducting crystals can be effectively eliminated. [27,28] Thus, 2DMCs are extremely fascinating for the direct exploration of the charge accumulation and transport behaviors regarding the properties of the semiconductor/insulator interface, disorder effects, and polaronic relaxation. Especially, in 2DMCbased FETs, the inter facial interactions on the molecular crystals can be well con fined at 2D limit, exhibiting different influences from layer to layer. Thus, the microscopic behaviors of charge carriers can be much effectively modulated. Therefore, 2DMCs possess unique optoelectronic properties that cannot be achieved in conven tional bulk molecular crystals. [29][30][31] Besides, utilizing their ultrathin structural features and superior interface qualities can significantly contribute to the enhanced performance of 2DMC based functional FETs. These unique merits, combined with intrinsic properties, such as lightweight construction, material versatility, and chemical/environment stability, explicitly enable these 2D crystals fascinating prospects for realistic applications in advanced electronic technologies. [15,[32][33][34][35] Obtaining molecular crystals with 2D morphology is an essential prerequisite for scientific and technological studies. Pioneering efforts have been devoted to vaporgrown 2DMCs. [36][37][38][39][40][41][42] However, the expensive preparation cost and rigorous growth conditions have rendered these methods Based on intensive research, organic field-effect transistors (OFETs) will likely remain at the zenith in information science for many years due to their numerous potential applications in portable and smart electronic devices. Elucidating the intrinsic charge-transport behavior and realizing functional OFETs with superior device characteristics have been the cornerstones for the sustainable advancement in organic electronics. The emerging 2D molecular crystal...

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Bar-coated high-performance organic thin-film transistors based on ultrathin PDFDT polymer with molecular weight independence

Cited by 16 publications

References 24 publications

Marangoni‐Effect‐Assisted Bar‐Coating Method for High‐Quality Organic Crystals with Compressive and Tensile Strains

Marangoni‐Effect‐Assisted Bar‐Coating Method for High‐Quality Organic Crystals with Compressive and Tensile Strains

Bar-Coated Ultrathin Semiconductors from Polymer Blend for One-Step Organic Field-Effect Transistors

Solution‐Processed 2D Molecular Crystals: Fabrication Techniques, Transistor Applications, and Physics

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