The importance of spinning speed in fabrication of spin-coated organic thin film transistors: Film morphology and field effect mobility

Kotsuki, Kenji; Tanaka, Hiroshige; Obata, Seiji; Stauss, Sven; Terashima, Kazuo; Saiki, Koichiro

doi:10.1063/1.4883216

Cited by 59 publications

(42 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Organic semiconductors have been spin-coated onto substrates to fabricate high-performance organic field-effect transistors (OFETs) that have attracted particular attention as key elements for realizing next-generation flexible printed electronics 7 8 9 10 11 12 . The performances of OFETs prepared by spin-coating are strongly correlated with the morphology and solid-state order of the deposited semiconducting layer 13 14 , and these properties depend significantly on the processing conditions applied during spin-coating, such as the solvent properties 15 16 , the substrate temperature 17 18 19 and surface characteristics 20 21 , the ambient solvent vapor pressure 22 , and the spinning speed 23 24 or time. The careful adjustment of all processing parameters can maximize the performance of the OFETs fabricated by spin-coating, given the inherent limitations of the semiconducting material.…”

mentioning

confidence: 99%

Understanding Solidification of Polythiophene Thin Films during Spin-Coating: Effects of Spin-Coating Time and Processing Additives

Kang

Sin

et al. 2015

Sci Rep

129

View full text Add to dashboard Cite

Spin-coating has been used extensively in the fabrication of electronic devices; however, the effects of the processing parameters have not been fully explored. Here, we systematically characterize the effects of the spin-coating time on the microstructure evolution during semiconducting polymer solidification in an effort to establish the relationship between this parameter and the performances of the resulting polymer field-effect transistors (FETs). We found that a short spin-coating time of a few seconds dramatically improve the morphology and molecular order in a conjugated polymer thin film because the π-π stacking structures formed by the polymer molecules grow slowly and with a greater degree of order due to the residual solvent present in the wet film. The improved ordering is correlated with improved charge carrier transport in the FETs prepared from these films. We also demonstrated the effects of various processing additives on the resulting FET characteristics as well as on the film drying behavior during spin-coating. The physical properties of the additives are found to affect the film drying process and the resulting device performance.

show abstract

mentioning

confidence: 99%

Understanding Solidification of Polythiophene Thin Films during Spin-Coating: Effects of Spin-Coating Time and Processing Additives

Kang

Sin

et al. 2015

Sci Rep

129

View full text Add to dashboard Cite

show abstract

“…22 Solution-processed graphene oxide bottom-contacts have been also utilised though exhibiting nonlinear output characteristics. 23 OFETs were fabricated on Si n++ /SiO 2 substrates with a bottom-gate top-contact configuration (Figure 3a). Blends of C8-BTBT with polystyrene in a ratio of 4:1 and dissolved in anhydrous chlorobenzene (2 % wt) were casted by bar-assisted meniscus shearing as previously reported.…”

Section: -Results and Discussionmentioning

confidence: 99%

Spray-coated contacts from an organic charge transfer complex solution for organic field-effect transistors

Georgakopoulos

Pérez-Rodríguez

Campos

et al. 2017

Organic Electronics

View full text Add to dashboard Cite

We demonstrate the deposition of films of the conducting charge transfer complex TTF-TCNQ from solution by spray coating. The benefit of spray coating is the ability to process large volumes of solution, therefore allowing the utilisation of compounds with very low solubility. The sheet resistance in the TTF-TCNQ film is similar to that of the commonly used organic PEDOT:PSS electrodes, with the added benefit of room temperature deposition and no additional thermal treatments. Spray coated TTF-TCNQ is used as source and drain electrodes for transistors based on the organic semiconductor C8-BTBT, achieving similar performances in terms of mobility and turn-on voltage than when conventional contacts of MoO x /Au are used, whilst exhibiting a slight improvement in the linearity of the output characteristics.

show abstract

“…Several morphology control strategies to overcome this issue have been reported, including solvent engineering, which provides large ordered domains originating from interactions between solvent and conjugated polymers; applying shear force to organic semiconductors using various printing methods; and other shear alignment methods including off‐center spin coating, which applies centrifugal force to substrate away from the spin coater axis . However, it is essential to understand the kinetics of drying from a deposited solution in order to obtain optimized polymer film morphology, which is strongly correlated with various processing conditions such as solvent, substrate temperature, and spinning speed . Recent studies have also investigated the role of residual solvents during film formation of polymeric semiconductors using short spinning time and solvent additives, which allow changing the degree of ordering of the polymer molecules and hence changing OFET device electrical characteristics.…”

Section: Introductionmentioning

confidence: 99%

Kinetically Controlled Crystallization in Conjugated Polymer Films for High‐Performance Organic Field‐Effect Transistors

Kim

Kim²,

Park

et al. 2019

Adv Funct Materials

View full text Add to dashboard Cite

Ordering of semiconducting polymers in thin films from the nano to microscale is strongly correlated with charge transport properties as well as organic field-effect transistor performance. This paper reports a method to control nano to microscale ordering of poly{[N,N′-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} (P(NDI2OD-T2)) thin films by precisely regulating the solidification rate from the metastable state just before crystallization. The proposed simple but effective approach, kinetically controlled crystallization, achieves optimized P(NDI2OD-T2) films with large polymer domains, long range ordered fibrillar structures, and molecular orientation preferable for electron transport leading to dramatic morphological changes in both polymer domain sizes at the micrometer scale and molecular packing structures at nanoscales. Structural changes significantly increase electron mobilities up to 3.43 ± 0.39 cm 2 V −1 s −1 with high reliability, almost two orders of enhancement compared with devices from naturally dried films. Small contact resistance is also obtained for electron injection (0.13 MΩ cm), low activation energy (62.51 meV), and narrow density of states distribution for electron transport in optimized thin films. It is believed that this study offers important insight into the crystallization of conjugated polymers that can be broadly applied to optimize the morphology of semiconducting polymer films for solution processed organic electronic devices.flexibility, unique electronic properties, and simple and cost effective printing processes. [1][2][3] Since charge transport in semiconducting polymer films depends mainly on charge hopping along both intramolecular and intermolecular π-orbitals, it is important to control crystalline grain size and connectivity at conjugated polymer grain boundaries to obtain high performance organic field-effect transistors (OFETs). [4][5][6][7] Several strategies have been reported to control conjugated polymer film morphology for high performance OFETs including the most widely used method being thermal annealing method. [8][9][10] Simple thermal annealing can improve the performance of almost all polymer transistors to some extent, but optimum morphology for efficient charge transport must still show precisely controlled grain sizes and boundaries. Several morphology control strategies to overcome this issue have been reported, including solvent engineering, which provides large ordered domains originating from interactions between solvent and conjugated polymers; [11,12] applying shear force to organic semiconductors using various printing methods; [13][14][15][16][17][18][19][20] and other shear alignment methods including off-center spin coating, which applies centrifugal force to substrate away from the spin coater axis. [12,[21][22][23][24] However, it is essential to understand the kinetics of drying from a deposited solution in

show abstract

The importance of spinning speed in fabrication of spin-coated organic thin film transistors: Film morphology and field effect mobility

Cited by 59 publications

References 15 publications

Understanding Solidification of Polythiophene Thin Films during Spin-Coating: Effects of Spin-Coating Time and Processing Additives

Understanding Solidification of Polythiophene Thin Films during Spin-Coating: Effects of Spin-Coating Time and Processing Additives

Spray-coated contacts from an organic charge transfer complex solution for organic field-effect transistors

Kinetically Controlled Crystallization in Conjugated Polymer Films for High‐Performance Organic Field‐Effect Transistors

Contact Info

Product

Resources

About