주요 논문
5
*2026년 기준 최근 6년 이내 논문에 한해 Impact Factor가 표기됩니다.
1
Article
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인용수 6
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2025Synthesis of a Stable Radical Cation of Bis‐Tert‐Butyl Ethylenedioxythiophene and its Application as a Dopant in Organic Semiconductors
Yeasin Khan, Jae Hyun Lee, Jin Hee Lee, Nathan Plassais, Faiza Shoukat, Jung Hwa Seo, Bright Walker
IF 12.1 (2025)
Small
Abstract A highly stable molecular radical cation (RC) derived from ethylenedioxy thiophene (EDOT) is effectively utilized for the p‐doping of poly‐3‐hexylthiophene (P3HT), an organic semiconductor. The success of this process is due to efficient electron transfer from the highest occupied molecular orbital band of P3HT to the singly unoccupied molecular orbital of the radical cation species. Confirmation of the doping is experimentally confirmed through UV–vis‐NIR absorption spectroscopy and electron spin resonance spectroscopy. The ability to dope the conjugated polymers PBTTT and PTB7 is also spectroscopically confirmed. An increase in work‐function of P3HT upon doping is observed due to electron transfer from P3HT to the radical cation with a concomitant decrease in the Fermi energy of P3HT. Impedance and four point probe analysis showed that the doped polymer films exhibited a significant decrease in resistance compared to the pristine films. This work presents the first use of a stable, easily synthesized EDOT‐based radical cation as a molecular p‐dopant for conjugated polymers, offering a novel and broadly applicable alternative to traditional dopants such as F 4 TCNQ.
https://doi.org/10.1002/smll.202503035
Dopant
HOMO/LUMO
Thiophene
Materials science
Electron paramagnetic resonance
Radical ion
Doping
Conjugated system
Organic semiconductor
Conductive polymer
2
Article
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인용수 3
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2025Diverse Metal Ion Polyelectrolytes as Hole Transport Layers for Quasi‐2D Perovskite Light‐Emitting Diodes
Faiza Shoukat, Seongbeom Lee, Jin Hee Lee, Yeasin Khan, Bright Walker, Sung Heum Park, Jung Hwa Seo
IF 6.2 (2025)
Advanced Materials Technologies
Abstract This work investigates the role of metal ion‐doped (Cs + , Ni 2+ , and Cu 2+ ) PEDOT:PSS films as hole transport layers (HTLs) in quasi‐2D perovskite light‐emitting diodes (PeLEDs). These HTLs lead to enhanced device performance through reduced defect density, improved hole mobility, and prolonged photoluminescence lifetime. X‐ray diffraction (XRD) reveals structural modifications in CsPbBr 3 films, with enhanced crystallinity resulting from the elimination of excess long‐chain cations. Morphological analyses using scanning electron microscopy (SEM) and atomic force microscopy (AFM) demonstrate the influence of metal doping on surface coverage and nanoscale roughness. Time‐resolved photoluminescence (TR‐PL) analysis confirms reduced nonradiative recombination, supporting improved film quality. Devices with Ni:PEDOT:PSS exhibit the highest external quantum efficiency, while Cs:PEDOT:PSS and Cu:PEDOT:PSS offer enhanced stability, achieving significantly longer operational lifetimes. These findings highlight the potential of metal‐doped PEDOT:PSS in optimizing the structural, optical, and electrical properties of perovskite materials, paving the way for more stable and efficient PeLEDs.
https://doi.org/10.1002/admt.202401684
Polyelectrolyte
Materials science
Optoelectronics
Perovskite (structure)
Diode
Light-emitting diode
Metal
Ion
Chemical engineering
Chemistry
3
Article
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인용수 7
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2024Practical organic electronic noses using semi-permeable polymer membranes
J.Y. Kim, Farjana Haque, Jae Hyun Lee, Yu Jung Park, Jung Hwa Seo, Mallory Mativenga, Bright Walker
IF 6.9 (2024)
Applied Materials Today
https://doi.org/10.1016/j.apmt.2024.102137
Membrane
Polymer
Materials science
Polymer science
Composite material
Chemistry
4
Article
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인용수 10
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2024Photoelectron Spectroscopic Study of the Interfacial Electronic Structures of Metal‐Ion Containing Polyelectrolytes on ITO Substrates
Jin Hee Lee, Yeasin Khan, Seung‐Hwan Kim, Ae Jin Choi, Bright Walker, Soohyung Park, Jung Hwa Seo
IF 19 (2024)
Advanced Functional Materials
Abstract Research in the field of organic electronics has witnessed dramatic improvements in device performance over the past several decades through an ever‐improving understanding of electron and hole movement and the development of new interfacial materials. In this study, a type of interfacial material that relies on ionic charges comprising metal:poly(styrenesulfonate) (PSS) polyelectrolytes are synthesized and investigated as structural analogs of the ubiquitously used poly(3,4‐ethylenedioxythiophene:polystyrenesulfonate) (PEDOT:PSS) hole transport layer, in order to investigate correlations between metal cation ions and the cationic PEDOT component. The metal ions selected for this study include Li, Mg, V, Mn, Co, Ni, Cu, Zn, Pd, Ag, Cs, and Pb ions. To analyze the interfacial energy level alignment, electronic band structure, and band bending at the Indium tin oxide (ITO)/metal:PSS interface, X‐ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) are employed. Alkali (earth) and post‐transition metals show deep highest occupied molecular orbital (HOMO) levels and low work function (WF) due to Fermi level balance, implying poor hole transport. Remarkably, Cu:PSS displays a unique electronic structure, suggesting potential as a hole transport layer with increased WF and low hole injection barrier. Period 5 transition metals mirror PEDOT:PSS trends, and Ag:PSS holds the potential to form effective ohmic contacts.
https://doi.org/10.1002/adfm.202315074
Materials science
X-ray photoelectron spectroscopy
Polyelectrolyte
Metal
Ion
Chemical engineering
Nanotechnology
Chemical physics
Polymer
Organic chemistry
5
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인용수 11
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2022Organic cation – polystyrene sulfonate polyelectrolytes as hole transporting interfacial layers in perovskite solar cells
Yeasin Khan, Yohan Ahn, Ju Hwan Kang, Azmat Ali, Yu Jung Park, Bright Walker, Jung Hwa Seo
IF 6.7 (2022)
Applied Surface Science
https://doi.org/10.1016/j.apsusc.2022.152826
Polystyrene sulfonate
Polyelectrolyte
PEDOT:PSS
Polystyrene
X-ray photoelectron spectroscopy
Work function
Materials science
Perovskite (structure)
Sulfonate
Ultraviolet photoelectron spectroscopy