Jong Dae Kim

Bio: Jong Dae Kim is an academic researcher from Soongsil University. The author has contributed to research in topics: Polymer brush & Polymer. The author has an hindex of 3, co-authored 3 publications receiving 125 citations.

A polymer brush organic interlayer improves the overlying pentacene nanostructure and organic field-effect transistor performance

Abstract: We investigated the crystalline nanostructures and film morphologies of pentacene films deposited onto a polymer brush organic interlayer in high performance organic field-effect transistors (OFETs). Polymer brushes were grafted onto the oxide substrates by spin-coating and thermal annealing. Pentacene FETs fabricated on top of the polymer brushes showed excellent device performance, with a field-effect mobility of 0.82 cm2 V−1s−1 and an on/off current ratio of 107. These properties were superior to those of devices using typical surface modification techniques, such as octadecyltrichlorosilane (ODTS) and hexamethyldisilazane (HMDS). The improvements in OFET performance appeared to be due to the pentacene layer's crystalline nanostructure and grain interconnectivity, which formed during the submonolayer stage of film growth. This stage of growth is strongly correlated with the surface energy, morphology, and viscoelastic properties of the resulting gate dielectrics. The inclusion of a polymer brush dielectric surface modification is a significant step toward optimizing the nanostructures of organic semiconductors, which are directly linked to device performance enhancement, by engineering the interfaces in OFETs.

Polymer brush as a facile dielectric surface treatment for high-performance, stable, soluble acene-based transistors

Abstract: We developed a facile dielectric surface modification using “grafting to” polymer brushes for high-performance and stable TES-ADT FETs. Polymer brushes were grafted onto oxide substrates by spin-coating and thermal annealing. TES-ADT FETs fabricated on top of the polymer brush layer showed excellent device performance−a field-effect mobility of 0.84 cm2/(V s) and an on/off current ratio of 1 × 106−that was superior to that of devices using conventional dielectric surface treatments such as HMDS and ODTS. During solvent annealing of the TES-ADT films, the mobile chains of the polymer brushes appear to profoundly influence the diffusion and crystallization of the TES-ADT molecules, while maximizing the π−π interactions along the in-plane direction. Moreover, the polymer brushes yielded excellent electrical and environmental stability because of the complete surface coverage with minimal pinholes and defects.

Interpenetrating polymer network dielectrics for high-performance organic field-effect transistors

Abstract: We have demonstrated the preparation of interpenetrating polymer network (IPN) dielectrics for use in high-performance organic field-effect transistors by blending commercially available polymers (PMMA, PtBMA, and PS) with the crosslinkable polymeric silsesquiazane (SSQZ) This facile blending method is a powerful means of enhancing the electrical strength of polymer dielectrics due to the formation of a siloxane network structure interspersed among the polymer chains We found that the leakage currents for the PMMA and PtBMA gate dielectrics blended with SSQZ significantly decreased, by as much as two orders of magnitude, compared with the pristine cases These remarkable enhancements in the dielectric properties arose from decreases in the free volume and in the thermal dynamic motions of the polymer chains due to formation of the polysiloxane network The IPN gate dielectrics provide a facile method for using commercially available polymers to fabricate polymer gate dielectrics with strong electrical strengths

Polymer brushes here, there, and everywhere: Recent advances in their practical applications and emerging opportunities in multiple research fields

Abstract: Bottom-up surface processing with well-defined polymeric structures becomes increasingly important in many current technologies. Polymer brushes, that is, assemblies of macromolecules tethered at one end to a substrate, provide an exemplary system of materials capable of achieving such a goal. While the focus in the past decades has been mostly on their synthetic aspects and the in-depth study of their interesting properties, from several years now the core area of research has already started to shift towards specific practical applications. Ample functional versatility and relative ease of preparation are special strengths of polymer brushes, lending them a strong interdisciplinary character. To this end, this work is entirely dedicated to bringing together the latest research on applications of polymer brushes in multiple research fields. The aim of this review are twofold: first, to give a critical discussion of the current status of development of application-oriented research on polymer brushes, and second, to inform the reader as to what can be done with polymer brushes in multiple research fields. It is therefore hoped that the juxtaposition of perspectives from different disciplines in one place will stimulate and contribute to the ongoing process of cross-fertilization that is driving this fascinating and emerging area of polymer science. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Polymeric and ceramic silicon-based coatings – a review

Abstract: Silicon-based polymers are outstanding materials for coating applications. These compounds have excellent properties, such as strong adhesion to most substrates, and high chemical, thermal and UV resistance. Additionally, they can be converted into ceramic materials (polymer-derived ceramics) by a heat treatment and, in some cases, by chemical reactions or radiation. Hence, ceramic coatings can be obtained after deposition of the polymers by simple lacquer techniques. The properties and composition of polymeric and ceramic coatings can be changed by tailoring the chemical structure of the precursors or by the addition of fillers. This enables the preparation of coatings with a great variety of properties for different applications. In this review paper, the main aspects of the use of silicon polymers for coatings are elucidated. The advantages and disadvantages of these materials, and the processing methods developed are discussed. Finally, a summary of the applications and the prospects for future research are presented.

25th anniversary article: microstructure dependent bias stability of organic transistors.

Abstract: Recent studies of the bias-stress-driven electrical instability of organic field-effect transistors (OFETs) are reviewed. OFETs are operated under continuous gate and source/drain biases and these bias stresses degrade device performance. The principles underlying this bias instability are discussed, particularly the mechanisms of charge trapping. There are three main charge-trapping sites: the semiconductor, the dielectric, and the semiconductor-dielectric interface. The charge-trapping phenomena in these three regions are analyzed with special attention to the microstructural dependence of bias instability. Finally, possibilities for future research in this field are presented. This critical review aims to enhance our insight into bias-stress-induced charge trapping in OFETs with the aim of minimizing operational instability.

Organic transistors in the new decade: Toward n-channel, printed, and stabilized devices

Abstract: Significant progress has been made in designing organic semiconducting materials (OSCs) for the past few decades for organic field-effect transistors (OFETs). Much attention has been paid to the development of p-channel OSCs, with less but highly significant progress on n-channel OSCs. In this review, we focus on the advances made with OFETs in the last few years to achieve high performance in n-channel modes, air stability, and solution processability, leading to printable active electronics. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012