Hoseop Yun

Fluorinated molecular engineering of nonlinear optical cationic chromophores in organic salt crystals for ultrabroadband terahertz wave generation

Yu‐Jin Park, Jung-Wook Park, Michael Auer, Joo Won Shin et autres

Compact table-top terahertz time-domain spectroscopy systems capable of achieving ultrabroad bandwidths in the range of 1–12 THz, extending beyond the reach of conventional THz and infrared spectroscopy, are highly desirable for diverse spectroscopic applications. In this work, we report fluorinated molecular engineering …

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New fluoro-benzothiazolium crystals with non-centrosymmetric molecular ordering

Seungmin Kim, Mojca Jazbinšek, Woojin Yoon, Hoseop Yun et autres

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Efficient Off‐Diagonal Terahertz Crystals: Nonlinear Optical Organic Polymorphs with High Conformational Freedom Substituents

Jungkwon OH, Chaeyoon Kim, Mojca Jazbinšek, Woojin Yoon et autres

ABSTRACT For terahertz (THz) applications, we designed new organic salt crystals by introducing a substituent with high conformational freedom. In these crystals, 4‐ethylbenzenesulfonate (EBS) anions with an ethyl substituent exhibit a low rotational energy barrier along the C sp 3 ─C sp …

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Organic Terahertz Crystals with Unusual Chlorinated Electron Donors

Dong‐Joo Kim, Jung‐Wook Park, Chaeyoon Kim, Chae‐Won Lee et autres

Abstract Organic terahertz (THz) crystals with large optical nonlinearity and low phonon absorption are highly desirable for diverse THz applications. In this work, a novel molecular design strategy is introduced for developing high‐performance organic THz salt crystals by introducing highly polar chlorinated …

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Predictive factors for re-recurrence in papillary thyroid carcinoma following reoperation: a retrospective analysis

Sang Chun Park, Sang‐Ho Jo, Hoseop Yun, Yong Bin Kwon et autres

Background: Papillary thyroid carcinoma (PTC) generally has a favorable prognosis; however, recurrence occurs in up to 30% of cases following initial management. Re-recurrence presents additional clinical challenges, making it crucial to distinguish between persistent disease and true recurrence in order to optimize …

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Anisotropic Dynamic Disorder of π ‐Stacking and Static Disorder in Organic Electron Transporting Materials with Isomorphic Crystal Structures

Chae‐Won Lee, Uroš Puc, Jeong Hyeon Lee, Na Young Cho et autres

In organic semiconductors, charge transport is strongly correlated with intermolecular π – π interactions and the dynamic disorder caused by solid‐state phonon vibrations. However, for pure π – π stacking of semiconducting cores, solid‐state phonon vibrations and their directional characteristics are relatively …

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New phenolic organic salt crystals with large optical nonlinearity

Yu‐Jin Park, Jung-Wook Park, Chaeyoon Kim, Mojca Jazbinšek et autres

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Tetrafluorinated ionic organic terahertz crystals

Yu‐Jin Park, Chaeyoon Kim, Woojin Yoon, Hoseop Yun et autres

Developing new organic crystals for efficient broad terahertz (THz) wave generation remains challenging, as multiple critical material properties must be achieved simultaneously within a single crystal. In this work, we introduce a new series of organic nonlinear optical salt crystals tailored for …

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Crystal structure and photoluminescence properties of CuBr x I1 −x(melamine) (0 ≤ x ≤ 1) complexes

Donghyeon Kim, Fouzia Khefif, Woojin Yoon, Hoseop Yun et autres

Abstract Organic–inorganic copper(I) halide complexes have attracted attention due to their optoelectronic properties and non‐toxic nature. In this study, we systematically synthesized copper(I) halide melamine complexes as single crystals, (CuBr(melamine) and CuI(melamine)) and polycrystalline powders, CuBrxI1‐x(melamine) (0 ≤ x ≤ 1). The …

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Organic Terahertz Generators with Wide Entire‐Molecular Phonon‐Free Range and Their Application in Broadband Terahertz Spectroscopy

Yun‐Sang Lee, Chaeyoon Kim, Jungkwon OH, Woojin Yoon et autres

New organic nonlinear optical crystals with a broad range free from strong molecular phonon vibrations have been developed for dimple‐free THz wave generation. The newly designed 7‐fluoro‐2‐(4‐hydroxy‐3‐methylstyryl)‐1‐methylquinolin‐1‐ium (OM7FQ) crystals exhibiting an optimal order parameter feature a unique orthogonal cation–anion dipole coupling, in …

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Organic THz Crystals Based on Off‐Diagonal Optical Nonlinearity with Optimal In‐Plane Polar Axis

Chae‐Won Lee, Chaeyoon Kim, Woojin Yoon, Hoseop Yun et autres

Abstract Highly efficient off‐diagonal THz generators based on novel organic nonlinear optical single crystals with optimal polar axis orientation in the as‐grown crystal morphology are introduced. The newly developed fluorinated and non‐fluorinated cationic chromophores exhibit a non‐centrosymmetric crystal structure with P21 space …

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Chiral Cationic Chromophores: A New Class of Efficient Ultrabroadband Organic THz Crystals

Jeong‐A Yang, Chae‐Won Lee, Chaeyoon Kim, Michael Auer et autres

Abstract A strategic approach to develop efficient ultra‐broadband terahertz (THz) crystals involves the incorporation of different electron donating groups (EDGs) into cationic chromophores. In contrast to the widely utilized non‐cyclic 4‐(dimethylamino)phenyl (DA) EDG, cyclic 5‐membered 4‐(2‐(hydroxymethyl)pyrrolidine‐1‐yl)phenyl (PB) and cyclic 6‐membered 4‐(3‐(hydroxymethyl)piperidin‐1‐yl)phenyl (PN) …

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