Ewha Womans University · Engineering
Professor Byoung Hoon Lee's research lab specializes in the development and application of advanced organic electronic materials, with a focus on conjugated polyelectrolytes, semiconducting polymers, and graphene-based materials for next-generation optoelectronic and electronic devices. The lab investigates fundamental mechanisms of charge transport, interfacial engineering, and morphology control in organic field-effect transistors and organic solar cells, emphasizing precise tuning of work functions and ion dynamics. Innovative fabrication techniques such as controlled drop-casting and nanogrooved substrate templating are employed to achieve high-performance, flexible, and stable devices. The lab also pioneers residue-free graphene transfer methods and conductive polymer electrodes for transparent and flexible electronics.
Figures are computed from collected data and may differ slightly.
Despite the excellent work function adjustability of conjugated polyelectrolytes (CPEs), which induce a vacuum level shift via the formation of permanent dipoles at the CPE/metal electrode interface, the exact mechanism of electron injection through the CPE electron transport layer (ETL) remains unclear. In particular, understanding the ionic motion within the CPE ETLs when overcoming the sizable injection barrier is a significant challenge. Because the ionic functionality of CPEs is a key compo
Controlled device parameters of high-mobility polymer field-effect transistors (FETs) are demonstrated by modest doping and charge compensation. Through fleeting chemical vapor treatments of aligned poly[4-(4,4-dihexadecyl-4H-cyclopenta[1,2-b:5,4-b']dithiophen-2-yl)-alt-[1,2,5]thiadiazolo-[3,4-c]pyridine] (PCDTPT) thin films as the charge transport layer in the FET channel, the FET properties are tailored by controlling doping concentration of the PCDTPT adjacent to metal electrodes.
Abstract A new film‐casting method for polymer electrodes is reported, in which thickness‐controlled drop‐casting (TCDC), using polyaniline doped with camphorsulfonic acid (PANI:CSA) is used. By combining the advantages of conventional spin‐casting and drop‐casting methods, and by rigorously controlling the film formation parameters, flexible polymer electrodes with high conductivity and excellent transmittance can be produced. The PANI:CSA electrodes cast by the TCDC method exhibited constant t
We report the controlled nanomorphology of semiconducting polymers on chemically and mechanically stable nanogrooved polymer substrates. By employing silicon dioxide thin films with finely adjusted thicknesses on nanogrooved polymer substrates, semiconducting polymer thin films oriented and aligned along the nanogrooves were obtained. Organic field-effect transistors (OFETs) fabricated from the oriented semiconducting polymer, poly[4-(4,4-dihexadecyl-4H-cyclopenta[1,2-b:5,4-b']dithiophen-2-yl)-a
To achieve the broad utilization of the full functionality of graphene (GR) in devices, a transfer method should be developed that can simplify the process without leaving residue of the insulating supporting layer on the surface of GR. Furthermore, stable GR doping without the use of an insulating polymer is required. Here, a new GR transfer method that uses a popular conducting polymer, poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), is reported as a new supporting layer f
p-Type conjugated polyelectrolytes (CPEs) are developed as organic-based work-function-modifier materials for the broad work-function (WF) tunability of various metal electrodes. Facile oxidative treatments of n-type CPEs using various oxidants produce unprecedented p-type CPEs with reversed electronic properties corresponding to n-type CPEs, resulting in fine WF tuning of adjacent metal electrodes. This change leads to substantial increases in power conversion efficiency and lifetime of organic
To understand the effects rendered on the relevant basic physical properties and device function by controlling the regiochemistry of the cyclopenta[1,2-b:5,4-b']dithiophene-fluorobenzo[c][1,2,5]thiadiazole polymer (hereafter referred to as the CDT-FBT polymer), two polymers, the regiorandom polymer (RA) and regioregular version (RR), respectively, are synthesized and characterized. In addition, an efficient route for synthesizing a key monomer for RR using various synthesis scope and optimizing
By coating conjugated polyelectrolytes (CPEs) on metals, the work function (WF) of metals can be tuned by electric dipoles formed through the self‐assembly of cation–anion pairs on the side chains of CPEs. Recently, it has been reported that a pertinent oxidative doping of anionic CPEs results in a reversed direction in the net electric dipoles, thereby yielding opposite WF tunability compared with pristine CPEs. However, the fundamental mechanism of this reversed WF tunability is not clearly un
Regioregular yet near-amorphous indacenodithiophene-based polymers exhibit superior deformability as well as high mobility values up to 1.67 cm<sup>2</sup> V<sup>−1</sup> s<sup>−1</sup>.
Zinc oxide nanoparticle (ZnO-NP) thin films have been intensively used as electron transport layers (ETLs) in organic optoelectronic devices, but their moderate mechanical flexibility hinders their application to flexible electronic devices. This study reveals that the multivalent interaction between ZnO-NPs and multicharged conjugated electrolytes, such as diphenylfluorene pyridinium bromide derivative (DFPBr-6), can significantly improve the mechanical flexibility of ZnO-NP thin films. Intermi
Despite the emerging scientific interest in polymer-based stretchable electronics, the trade-off between the crystallinity and stretchability of intrinsically stretchable polymer semiconductors-charge-carrier mobility increases as crystallinity increases while stretchability decreases-hinders the development of high-performance stretchable electronics. Herein, a highly stretchable polymer semiconductor is reported that shows concurrently improved thin film crystallinity and stretchability upon t
Atomic and molecular layer deposition (ALD & MLD) techniques can be used to fabricate various hybrid organic-inorganic polymer films. One class of hybrid organic-inorganic films are metal alkoxide polymers that are formed from organometallic precursors and organic alcohols. These metal alkoxide polymers are called "metalcones". The metalcones can also be mixed with metal oxides to grow metalcone/metal oxide alloys. This paper will overview some of the new metalcones and metalcone/metal oxide
This study suggests that the available multi-dose nebulized solution is generally safe. However, significant bronchoconstriction can occur at a relatively low BAC dose in asthmatics with severe airway responsiveness.
Polymer semiconductors with hysteresis-free ambipolar charge transport characteristics are key elements for developing high-performance organic field-effect transistors and circuits. In this study, a new and facile strategy of simply reconfiguring the donor (D) and acceptor (A) moieties in the order D–A–A–D in the repeat units was proposed to prepare D–A-type polymer semiconductors with enhanced electron and hole mobilities and hysteresis-free transistor characteristics. In contrast to the conve
Although rapid and remarkable progress has been made in semiconducting polymers used in organic field‐effect transistors (OFETs), the development of novel π‐conjugated backbones remains the central issue in this field. High FET mobilities have been achieved for copolymers based on fused‐ring building blocks due to their strong tendency to form ππ stacks. However, introducing the recently formulated strong electron‐rich fused‐ring dithienopyran (DTP) unit in the polymer backbone has garnered con
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