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Centro-Apical Self-Organization of Organic Semiconductors in a Line-Printed Organic Semiconductor: Polymer Blend for One-Step Printing Fabrication of Organic Field-Effect Transistors.

Lee SJ, Kim YJ, Yeo SY, Lee E, Lim HS, Kim M, Song YW, Cho J, Lim JA - Sci Rep (2015)

Bottom Line: Key feature of this work is that organic semiconductor molecules were vertically segregated on top of the polymer phase and simultaneously crystallized at the center of the printed line pattern after solvent evaporation without an additive process.The thickness and width of the centro-apically segregated organic semiconductor crystalline stripe in the printed blend pattern were controlled by varying the relative content of the organic semiconductors, printing speed, and solution concentrations.Finally, a centro-apically phase-separated bilayer structure of organic semiconductor: polymer blend was successfully demonstrated as a facile method to form the semiconductor and dielectric layer for OFETs in one- step.

View Article: PubMed Central - PubMed

Affiliation: Center for Opto-Electronic Materials and Devices, Post-Silicon Semiconductor Institute, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea.

ABSTRACT
Here we report the first demonstration for centro-apical self-organization of organic semiconductors in a line-printed organic semiconductor: polymer blend. Key feature of this work is that organic semiconductor molecules were vertically segregated on top of the polymer phase and simultaneously crystallized at the center of the printed line pattern after solvent evaporation without an additive process. The thickness and width of the centro-apically segregated organic semiconductor crystalline stripe in the printed blend pattern were controlled by varying the relative content of the organic semiconductors, printing speed, and solution concentrations. The centro-apical self-organization of organic semiconductor molecules in a printed polymer blend may be attributed to the combination of an energetically favorable vertical phase-separation and hydrodynamic fluids inside the droplet during solvent evaporation. Finally, a centro-apically phase-separated bilayer structure of organic semiconductor: polymer blend was successfully demonstrated as a facile method to form the semiconductor and dielectric layer for OFETs in one- step.

No MeSH data available.


(a) Photo image (left) and OM images (right) of a diF-TESADT:PMMA (1:8 w/w ratio) blend printed line transistor array on a PES substrate. (b) Statistical distribution of the field-effect mobilities. (c) Output (IDS–VDS) and (d) transfer (IDS–VGS) characteristics (at VDS = −80 V) of a diF-TESADT:PMMA (1:8 w/w ratio) blend printed line transistor.
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f6: (a) Photo image (left) and OM images (right) of a diF-TESADT:PMMA (1:8 w/w ratio) blend printed line transistor array on a PES substrate. (b) Statistical distribution of the field-effect mobilities. (c) Output (IDS–VDS) and (d) transfer (IDS–VGS) characteristics (at VDS = −80 V) of a diF-TESADT:PMMA (1:8 w/w ratio) blend printed line transistor.

Mentions: Additionally, we verified the feasibility of this method to fabricate flexible devices and direct-print organic semiconductor channels that were well defined within channel-lengths of as low as 10 μm. Flexible OFETs with short channel lengths were constructed on a polyethersulfone (PES) substrate by printing a 1:8 diF-TESADT:PMMA blend solution, as shown in Fig. 6a. As shown in Fig. 6c,d, the output and transfer characteristics of the devices exhibited a gate-bias response, and there was no contact barrier for charge injection from the electrodes. This verified that the centro-apically segregated diF-TESADT molecules from a 1:8 diF-TESADT:PMMA blend solution were densely packed and formed a crystalline film for the efficient transport of charge carriers. The average field-effect mobilities and on/off current ratios of these flexible OFETs with a 10 μm channel length were approximately 0.03 cm2V−1s−1 and 105, respectively. When the devices were fabricated on the glass substrate using a 1:8 diF-TESADT:PMMA blend solution the device performances were consistent with that of the devices based on the flexible substrate. (Fig. S8 in SI) The best performance of the one-step printed flexible OFET has field-effect mobility of 0.07 cm2V−1s−1 and on/off current ratio of 107. Relatively lower mobility of this device compared with the value of the devices prepared from the 1:4 diF-TESADT:PMMA blend solution might be due to an incomplete phase-separation and less-ordering of the diF-TESADT blend solution with a small amount of diF-TESADT in the viscous blend solution because the self-organizing movement of the diF-TESADT molecules in the more viscous solution could be restricted11. The transistor performance of the device printed from the 1:8 diF-TESADT:PMMA solution will be improved by adjusting the viscosity of the blend solution.


Centro-Apical Self-Organization of Organic Semiconductors in a Line-Printed Organic Semiconductor: Polymer Blend for One-Step Printing Fabrication of Organic Field-Effect Transistors.

Lee SJ, Kim YJ, Yeo SY, Lee E, Lim HS, Kim M, Song YW, Cho J, Lim JA - Sci Rep (2015)

(a) Photo image (left) and OM images (right) of a diF-TESADT:PMMA (1:8 w/w ratio) blend printed line transistor array on a PES substrate. (b) Statistical distribution of the field-effect mobilities. (c) Output (IDS–VDS) and (d) transfer (IDS–VGS) characteristics (at VDS = −80 V) of a diF-TESADT:PMMA (1:8 w/w ratio) blend printed line transistor.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4566135&req=5

f6: (a) Photo image (left) and OM images (right) of a diF-TESADT:PMMA (1:8 w/w ratio) blend printed line transistor array on a PES substrate. (b) Statistical distribution of the field-effect mobilities. (c) Output (IDS–VDS) and (d) transfer (IDS–VGS) characteristics (at VDS = −80 V) of a diF-TESADT:PMMA (1:8 w/w ratio) blend printed line transistor.
Mentions: Additionally, we verified the feasibility of this method to fabricate flexible devices and direct-print organic semiconductor channels that were well defined within channel-lengths of as low as 10 μm. Flexible OFETs with short channel lengths were constructed on a polyethersulfone (PES) substrate by printing a 1:8 diF-TESADT:PMMA blend solution, as shown in Fig. 6a. As shown in Fig. 6c,d, the output and transfer characteristics of the devices exhibited a gate-bias response, and there was no contact barrier for charge injection from the electrodes. This verified that the centro-apically segregated diF-TESADT molecules from a 1:8 diF-TESADT:PMMA blend solution were densely packed and formed a crystalline film for the efficient transport of charge carriers. The average field-effect mobilities and on/off current ratios of these flexible OFETs with a 10 μm channel length were approximately 0.03 cm2V−1s−1 and 105, respectively. When the devices were fabricated on the glass substrate using a 1:8 diF-TESADT:PMMA blend solution the device performances were consistent with that of the devices based on the flexible substrate. (Fig. S8 in SI) The best performance of the one-step printed flexible OFET has field-effect mobility of 0.07 cm2V−1s−1 and on/off current ratio of 107. Relatively lower mobility of this device compared with the value of the devices prepared from the 1:4 diF-TESADT:PMMA blend solution might be due to an incomplete phase-separation and less-ordering of the diF-TESADT blend solution with a small amount of diF-TESADT in the viscous blend solution because the self-organizing movement of the diF-TESADT molecules in the more viscous solution could be restricted11. The transistor performance of the device printed from the 1:8 diF-TESADT:PMMA solution will be improved by adjusting the viscosity of the blend solution.

Bottom Line: Key feature of this work is that organic semiconductor molecules were vertically segregated on top of the polymer phase and simultaneously crystallized at the center of the printed line pattern after solvent evaporation without an additive process.The thickness and width of the centro-apically segregated organic semiconductor crystalline stripe in the printed blend pattern were controlled by varying the relative content of the organic semiconductors, printing speed, and solution concentrations.Finally, a centro-apically phase-separated bilayer structure of organic semiconductor: polymer blend was successfully demonstrated as a facile method to form the semiconductor and dielectric layer for OFETs in one- step.

View Article: PubMed Central - PubMed

Affiliation: Center for Opto-Electronic Materials and Devices, Post-Silicon Semiconductor Institute, Korea Institute of Science and Technology (KIST), Seoul, 136-791, Korea.

ABSTRACT
Here we report the first demonstration for centro-apical self-organization of organic semiconductors in a line-printed organic semiconductor: polymer blend. Key feature of this work is that organic semiconductor molecules were vertically segregated on top of the polymer phase and simultaneously crystallized at the center of the printed line pattern after solvent evaporation without an additive process. The thickness and width of the centro-apically segregated organic semiconductor crystalline stripe in the printed blend pattern were controlled by varying the relative content of the organic semiconductors, printing speed, and solution concentrations. The centro-apical self-organization of organic semiconductor molecules in a printed polymer blend may be attributed to the combination of an energetically favorable vertical phase-separation and hydrodynamic fluids inside the droplet during solvent evaporation. Finally, a centro-apically phase-separated bilayer structure of organic semiconductor: polymer blend was successfully demonstrated as a facile method to form the semiconductor and dielectric layer for OFETs in one- step.

No MeSH data available.