Jaeyong Ahn

All Publications

• Thermally Driven Supramolecular Chirality Evolution in Low-Bandgap Fused-Ring Conjugated Molecules for High-Performance NIR Circularly Polarized Light Detection. Advanced science (Weinheim, Baden-Wurttemberg, Germany) Ahn, J., Kim, K., Lee, S., Lee, S., Hur, S., Kim, B., Oh, J. H. 2026: e76299

  Abstract

  Near-infrared (NIR) circularly polarized light (CPL) photodetection is of great importance due to its broad application potential in bioimaging, wearable healthcare, optical communication, and advanced optoelectronic systems. In this study, a supramolecular chirality evolution strategy in chiral low-bandgap fused-ring conjugated molecules (LFCs) is presented for high-performance NIR CPL photodetection using Schottky barrier vertical organic field-effect transistors (SB-VOFETs). Halogen substitution combined with thermal annealing drives inversion and amplification of supramolecular chirality in enantiopure LFC thin films. F-substituted LFCs exhibit progressive domain growth and hierarchical ordering with increasing annealing temperature, whereas Cl-substituted LFCs show limited structural evolution above 150°C. These distinct crystallization behaviors directly correlate with chiroptical responses, with F-substituted LFCs achieving a maximum absorption dissymmetry factor (|gabs|) of ∼0.1. When integrated into SB-VOFETs, the optimized chiral films enable highly efficient NIR CPL photodetection, delivering a photocurrent dissymmetry factor (|gph|) of ∼0.1, a specific detectivity of 4.9 × 101 1 Jones, an external quantum efficiency exceeding 900%, and a fast response time of ∼600 µs at 850 nm. These metrics represent the highest performance reported for NIR CPL. This study provides design guidelines for advancing high-performance chiral optoelectronic devices through the synergistic integration of atomic substitution, thermal annealing, and device architecture engineering.

  View details for DOI 10.1002/advs.76299

  View details for PubMedID 42365582

• Upcycling Commodity Polymers into Semiconductors by Sequential Grafting of Aromatic Units through Regioselective Iodination and Living Suzuki-Miyaura Catalyst-Transfer Polymerization. Journal of the American Chemical Society Zhang, J., Ahn, J., Park, H., Wu, R., Kim, H., Bao, Z., Choi, T. L. 2026

  Abstract

  Aromatic commodity polymers possess outstanding thermal and mechanical properties, however, despite recent advances in recycling and functionalization strategies, their reuse remains limited due to the restricted scope of available upcycling approaches. Here we report a sequential postpolymerization strategy that enables precise C-H iodination of aromatic polymers followed by controlled transformation into functional graft copolymers, preserving molecular weight and processability without inducing chain scission or cross-linking. Mild electrophilic iodination using hypervalent iodine reagents affords regioselective and tunable halogenation across a broad range of commodity plastics, including polystyrene, polysulfone, polycarbonate and mixed postconsumer wastes. The resulting iodinated polymers serve as well-defined macroinitiators for living Suzuki-Miyaura catalyst-transfer polymerization, enabling the growth of p- and n-type conjugated polymer from the commodity polymers with controlled grafting density and arm length. This approach preserves the intrinsic performance of the parent polymers while introducing new optoelectronic functionality. Further application to styrene-based elastomers leads to graft-induced microphase separation, yielding stretchable semiconducting materials with enhanced mechanical robustness and strain-resilient charge transport. This work establishes a general platform for functional upcycling of aromatic commodity plastics into advanced materials.

  View details for DOI 10.1021/jacs.6c08566

  View details for PubMedID 42307056

• Chirality amplification in semiconductors for advanced optoelectronics. Chemical Society reviews Ahn, J., Choi, W., Lee, S. H., Park, J., Kim, S., Song, I., Oh, J. H. 2025

  Abstract

  Because circularly polarized light (CPL) uniquely carries spin-selective information, chiral optoelectronics offer a powerful platform for developing high-efficiency, spin-based optical devices and driving next-generation photonic technologies. Intrinsically chiral semiconductors can absorb or emit CPL through light-matter interactions, positioning them as highly attractive active materials for advanced optoelectronics. However, their weak chiroptical activities often hinder practical implementation. To address this challenge, researchers have explored a range of strategies aimed at enhancing chiroptical performance. Recent advances in molecular design, processing techniques, and device engineering have led to significant improvements in the chiroptical properties of these materials. This review summarizes recent progress in chirality amplification strategies for semiconductors in advanced optoelectronics. Intrinsically chiral semiconductors are classified into three groups: organic semiconductors, metal-organic materials, and chiral hybrid perovskites. Furthermore, strategies for enhancing chiroptical signal output in chiral optoelectronic devices are discussed, supported by relevant theoretical frameworks. These advancements establish a solid foundation for the development of high-performance chiral optoelectronic devices, paving the way for future innovations in photonic technology.

  View details for DOI 10.1039/d5cs00684h

  View details for PubMedID 41292497

• High-performance flexible circularly polarized light photodetectors based on chiral n-type naphthalenediimide-bithiophene polymers NPJ FLEXIBLE ELECTRONICS Gao, K., Kim, S., Zhao, W., Ye, X., Wang, P., Liu, L., Ahn, J., Zhuo, H., Li, Z., Wang, Z., Chang, G., Ma, W., Zhang, M., Long, G., Shang, X., Oh, J. 2025; 9 (1)

  View details for DOI 10.1038/s41528-025-00443-2

  View details for Web of Science ID 001546042800001

• Circularly Polarized Light-Responsive Flexible Synapses Based on Supramolecular n-Type Chiral Organic Single Crystal/p-Type Polymer Heterojunctions. ACS nano Kim, B., Ahn, J., Gao, K., Shang, X., Oh, J. H. 2025

  Abstract

  Chiral neuromorphic devices that detect both circularly polarized light and digitized electrical signals are cutting-edge combinations of neuromorphic engineering and chiral optoelectronics that may advance both computing and sensing. In this work, organic electrochemical transistors (OECTs) based on n-type 2D organic single-crystal/p-type polymer heterojunctions are described. The supramolecular characteristics and molecular packing modes of the single crystals endowed the system with a high polarization selectivity. Furthermore, the integration of a p-n heterojunction facilitated modulation of charge trapping and separation at the interface, leading to improved chiroptical sensitivity. The devices emulate key features of biological synapses, including paired-pulse facilitation (PPF) and synaptic plasticity according to number, voltage, and frequency of spikes (SNDP, SVDP, and SFDP) under both electrical and optical stimulation. Leveraging these properties, the biocompatibility and flexibility of these synapse-like devices enabled the development of wearable chiral neuromorphic devices on flexible polyethylene naphthalate (PEN) substrates, highlighting their potential for advanced bioinspired applications such as humanoid robots. Additionally, the artificial nervous system based on a trained convolutional neural network successfully performs image classification work. These findings in chiral single-crystal-based artificial synapses suggest potential strategies for advanced opto-neuromorphic computing depending on the wavelength and circular polarization state.

  View details for DOI 10.1021/acsnano.5c07495

  View details for PubMedID 40719571

• Nearly 50-50 Face-on to Edge-on Crystallites in Regioisomeric Polymers Based on <i>n</i>-Type Thienylvinyl-1,1-dicyanomethylene-3-indanone for High Electron Mobility ACS APPLIED MATERIALS & INTERFACES Lee, S., Lee, S., Jeong, S., Ahn, J., Yang, S., Jeong, S., Cho, Y., Oh, J., Yang, C. 2025; 17 (27): 39366-39374

  Abstract

  To better understand how backbone regioregularity at the molecular level influences the bulk properties of conjugated polymers, we investigated the optical and electrochemical properties, energetics, microstructure, and charge transport characteristics of newly synthesized regioisomeric polymers. These include a regiorandom polymer (PTIC) and two regioregular analogs (PTIC-γ and PTIC-δ). All these polymers exhibit a broad infrared absorption band covering from 300 to 1000 nm, a narrow band gap of 1.25 eV, and a low-lying lowest unoccupied molecular orbital deeper than 3.88 eV. PTIC-γ features weaker chain-to-chain packing owing to its U-shape backbone, whereas PTIC and PTIC-δ present strong aggregation with their wave-like backbone shapes. Initially, all pristine polymer films reveal a bimodal texture dominated by a preferential face-on orientation. Following thermal annealing, the crystallites reorient further into a nearly exclusive face-on packing for PTIC-γ and PTIC-δ films, whereas PTIC films maintain a roughly 50-50 face-on to edge-on orientation ratio. As a result, the best electron mobility, reaching 1.43 × 10-1 cm2 V-1 s-1, is achieved from the annealed PTIC film owing to the construction of a continuous 3D charge-transport pathway.

  View details for DOI 10.1021/acsami.5c05769

  View details for Web of Science ID 001518545200001

  View details for PubMedID 40574321

• Stable Open-Shell Conjugated Terpolymer with Extended NIR Absorption for Organic Photodetectors Detecting Beyond 1000 nm ACS APPLIED MATERIALS & INTERFACES Jeong, M., Lee, S., Won, Y., Ahn, J., Kim, M., Oh, J. 2025: 25591-25601

  Abstract

  Near-infrared (NIR) photodetectors play crucial roles in many scientific, industrial, and medicinal fields. However, conventional organic photodetectors (OPDs) often do not utilize the NIR region due to poor absorption beyond 1000 nm. In this study, an open-shell conjugated terpolymer is synthesized for NIR detection. This polymer contains diketopyrrolopyrrole (DPP), thiophene, and benzo[1,2-c;4,5-c']bis[1,2,5]thiadiazole (BBT); these components form the novel random terpolymer poly{2,5-bis(2-decyltetradecyl)-3,6-di(thiophen-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione]-co-thiophene-co-benzo[1,2-c;4,5-c']bis[1,2,5]thiadiazole} (PDPPTBBT) via Stille coupling polymerization. The diradicals generated by the open-shell characteristics of PDPPTBBT become stronger as molecular packing is enhanced. This enhancement enables absorption at wavelengths beyond 1000 nm. PDPPTBBT exhibits temperature-independent Pauli paramagnetic properties. Additionally, electron paramagnetic resonance measurements reveal that compared with the singlet ground state, the polymer exhibits a higher stability in the triplet ground state and a high spin (S = 1). PDPPTBBT can act as an acceptor or a donor in films in which the material is blended with either poly(3-hexylthiophene-2,5-diyl) or Y6. OPDs prepared using the blended films display detection wavelengths exceeding 1000 nm with a maximum external quantum efficiency of 126% at 1050 nm and a specific detectivity (D*) of 7.5 × 1011 Jones.

  View details for DOI 10.1021/acsami.5c03911

  View details for Web of Science ID 001471670600001

  View details for PubMedID 40254972

• Metal-Oxide-Decorated Mesoporous Silica Chemiresistors for Exhaled Biomarker Detection ACS OMEGA Sung, M., Oh, M., Wang, T., Ahn, J., Oh, J., Stebe, K. J., Lee, D., Hwang, G., Kim, J. 2025; 10 (15): 15629-15636

  Abstract

  A metal-oxide-decorated mesoporous silica (MOMS) chemiresistor platform enables the selective detection of disease-specific volatile organic compounds (VOCs) in exhaled breath. Functionalization of these mesoporous structures with metals and metal oxides facilitates the detection of a wide range of VOCs. To create a sensing architecture with a bicontinuous morphology that optimizes molecular diffusion and electron transport pathways, we employ physically confined polymerization-induced phase separation (PC-PIPS) to fabricate template-directed mesoporous structures with controlled film thicknesses ranging from 1 to 5 μm. Incorporation of metal oxides (SnO2, ZnO) and noble metals (Pt, Au) forms p-n heterojunctions, enhancing sensitivity and selectivity through modulation of electron depletion layers. The MOMS chemiresistors demonstrate distinct response patterns toward key biomarkers, including hydrogen sulfide (periodontal disease), toluene (gingivitis), formaldehyde (oral carcinoma), and acetone (diabetes mellitus). Response magnitudes range from 1.75-5.66 at 10 ppm to 5.56-12.13 at 100 ppm of H2S, with unique electronic signatures, enabling identification of complex gas mixtures. This scalable and versatile fabrication approach establishes MOMS chemiresistors as a promising platform for noninvasive, early-stage disease detection via breath analysis.

  View details for DOI 10.1021/acsomega.5c00912

  View details for Web of Science ID 001465852700001

  View details for PubMedID 40290956

  View details for PubMedCentralID PMC12019497

• Enhancing optoelectronic performance of organic phototransistors through surface doping of tetra-bromo perylene diimide single crystals JOURNAL OF MATERIALS CHEMISTRY C Zhuo, H., Cho, Y., Gao, K., Wang, Z., Li, Z., Chu, X., Cui, T., Choi, W., Chang, G., Ahn, J., Shang, X., Oh, J. 2025; 13 (16): 8077-8083

  View details for DOI 10.1039/d5tc00361j

  View details for Web of Science ID 001448621900001

• Helical donor-acceptor bulk heterojunctions for dissymmetric circularly polarized light detection CHEMICAL ENGINEERING JOURNAL Song, I., Ahn, J., Lee, S., Lee, S., Kim, S., Cho, Y., Oh, J. 2025; 505

  View details for DOI 10.1016/j.cej.2024.158991

  View details for Web of Science ID 001400188200001

• Reversal of chirality in solutions and aggregates of chiral tetrachlorinated diperylene diimides towards efficient circularly polarized light detection MATERIALS HORIZONS Gao, K., Lee, S., Zhao, W., Ahn, J., Kim, T., Li, Z., Zhuo, H., Wang, Z., Zheng, X., Yan, Y., Chang, G., Ma, W., Zhang, M., Long, G., Oh, J., Shang, X. 2025; 12 (6): 1903-1912

  Abstract

  Helicenes exhibit promise as active layer materials for circularly polarized light (CPL) detectors due to their strong chiroptical activity. However, their practical application is limited by the complicated synthesis and loosely solid-state packing. This study introduces a chiral induction strategy towards the synthesis of helicene derivatives, chiral tetrachlorinated diperylene diimides ((SSSS)-4CldiPDI or (RRRR)-4CldiPDI). When incorporating the chiral (S/R)-1-cyclohexylethyl (Cy) substituents, the chirality is directly transferred to the π-aromatic core and forms the PP- or MM-helicene subunit. Notably, (SSSS)-Cy induces preferred PP helicity while (RRRR)-Cy leads to the MM helicity in the monomers. However, these molecules exhibit reversed chirality in crystals, where (SSSS)-Cy controls MM helicity and (RRRR)-Cy induces PP helicity. Theoretical calculations reveal that the (SSSS)-PP structure demonstrates lower energy distribution in monomers, whereas the (SSSS)-MM structure exhibits lower energy in crystals. Then, the CPL detection based on n-type PDI-helicene derivatives is achieved by using (SSSS)-4CldiPDI or (RRRR)-4CldiPDI crystals. The maximum photocurrent dissymmetry factor gph of +0.16 for (RRRR)-4CldiPDI and -0.15 for (SSSS)-4CldiPDI is obtained. Our work demonstrates a novel chiral induction strategy for designing helicene-based materials with both high dissymmetry factor and large charge carrier mobility, which offers great potential for the advancement of CPL detection.

  View details for DOI 10.1039/d4mh01435a

  View details for Web of Science ID 001378544000001

  View details for PubMedID 39688194

• Giant chiral amplification of chiral 2D perovskites via dynamic crystal reconstruction SCIENCE ADVANCES Kim, H., Choi, W., Kim, Y., Kim, J., Ahn, J., Song, I., Kwak, M., Kim, J., Park, J., Yoo, D., Park, J., Kwak, S., Oh, J. 2024; 10 (34): eado5942

  Abstract

  Chiral hybrid perovskites show promise for advanced spin-resolved optoelectronics due to their excellent polarization-sensitive properties. However, chiral perovskites developed to date rely solely on the interaction between chiral organic ligand cations exhibiting point chirality and an inorganic framework, leading to a poorly ordered short-range chiral system. Here, we report a powerful method to overcome this limitation using dynamic long-range organization of chiral perovskites guided by the incorporation of chiral dopants, which induces strong interactions between chiral dopants and chiral cations. The additional interplay of chiral cations with chiral dopants reorganizes the morphological and crystallographic properties of chiral perovskites, notably enhancing the asymmetric behavior of chiral 2D perovskites by more than 10-fold, along with the highest dissymmetry factor of photocurrent (gPh) of ~1.16 reported to date. Our findings present a pioneering approach to efficiently amplify the chiroptical response in chiral perovskites, opening avenues for exploring their potential in cutting-edge optoelectronic applications.

  View details for DOI 10.1126/sciadv.ado5942

  View details for Web of Science ID 001295497800023

  View details for PubMedID 39167654

  View details for PubMedCentralID PMC11338236

• Surface doping effect on the optoelectronic performance of 2D organic crystals based on cyano-substituted perylene diimides CHINESE CHEMICAL LETTERS Ahn, J., Li, Z., Wang, Z., Gao, K., Zhuo, H., Choi, W., Chang, G., Shang, X., Oh, J. 2024; 35 (9)

  View details for DOI 10.1016/j.cclet.2024.109777

  View details for Web of Science ID 001246320600001

• Boosting the Performance of Flexible Perovskite Photodetectors Using Hierarchical Plasmonic Nanostructures SMALL STRUCTURES Lee, Y., Lee, S., Won, Y., Kim, H., Yang, S., Ahn, J., Mun, J., Lee, J., Dou, L., Rho, J., Oh, J. 2024; 5 (7)

  View details for DOI 10.1002/sstr.202300546

  View details for Web of Science ID 001198768300001

• Impact of Packing Geometry on Excimer Characteristics and Mobility in Perylene Bisimide Polycrystalline Films ACS APPLIED MATERIALS & INTERFACES Kang, S., Choi, W., Ahn, J., Kim, T., Oh, J., Kim, D. 2024; 16 (14): 18134-18143

  Abstract

  Efficient exciton transport is essential for high-performance optoelectronics. Considerable efforts have been focused on improving the exciton mobility in organic materials. While it is feasible to improve mobility in organic systems by forming well-ordered stacks, the formation of trap states, particularly the lower-lying states referred to as excimers, remains a significant challenge to enhancing mobility. The mobility of excimer excitons intricately depends on the strength of excitonic coupling in terms of Förster-type diffusive exciton transfer processes. Given that the formation and mobility of excimer excitons are highly sensitive to molecular arrangements (packing geometries), conducting comprehensive investigations into the structure-property relationship in organic systems is crucial. In this study, we prepared three types of polycrystalline films of perylene bisimide (PBI) by varying substituents at the imide and bay positions, which allowed us to tailor the properties of excimer excitons and their mobility based on packing geometries and excitonic coupling strengths. By utilizing femtosecond transient absorption spectroscopy, we observed ultrafast excimer formation in the higher coupling regime, while in the lower coupling regime, the transition from Frenkel to excimer excitons occurs with a time constant of 500 fs. Under high pump-fluence, exciton-exciton annihilation processes occur, indicating the diffusion of excimer excitons. Intriguingly, employing a three-dimensional diffusion model, we derived a diffusion constant that is 3000 times greater in the high coupling regime than in the low coupling regime. To investigate the optoelectronic properties in the form of a bulk system, we fabricated n-type organic field effect transistors and obtained 8000 times higher mobility in the high coupling regime. Furthermore, photocurrent measurements enable us to investigate the charge carrier transport by mobile excimer excitons, suggesting a 230-fold improvement in external quantum efficiency with tightly packing PBI molecules compared to the low coupling regime. These findings not only offer valuable insights into optimizing organic materials for optoelectronic devices but also unveil the intriguing potential of exciton migration within excimers.

  View details for DOI 10.1021/acsami.3c19140

  View details for Web of Science ID 001194453900001

  View details for PubMedID 38554079

• Chiral organic semiconducting materials for next-generation optoelectronic sensors DEVICE Ahn, J., Lee, S., Song, I., Chidchob, P., Kwon, Y., Oh, J. 2023; 1 (5)

  View details for DOI 10.1016/j.device.2023.100176

  View details for Web of Science ID 001340489400004

• Ligand-Tuned Perylene Diimide-Based Versatile Coordination Polymers for Photoluminescent Sensing and Optoelectronics ADVANCED OPTICAL MATERIALS Shang, X., Song, I., Lee, J., Kim, J., Ohtsu, H., Choi, W., Ahn, J., Gao, K., Zhang, M., Kawano, M., Kwak, S., Oh, J. 2023; 11 (19)

  View details for DOI 10.1002/adom.202300534

  View details for Web of Science ID 001016078600001

• Helical polymers for dissymmetric circularly polarized light imaging NATURE Song, I., Ahn, J., Ahn, H., Lee, S., Mei, J., Kotov, N. A., Oh, J. 2023; 617 (7959): 92-+

  Abstract

  Control of the spin angular momentum (SAM) carried in a photon provides a technologically attractive element for next-generation quantum networks and spintronics1-5. However, the weak optical activity and inhomogeneity of thin films from chiral molecular crystals result in high noise and uncertainty in SAM detection. Brittleness of thin molecular crystals represents a further problem for device integration and practical realization of chiroptical quantum devices6-10. Despite considerable successes with highly dissymmetric optical materials based on chiral nanostructures11-13, the problem of integration of nanochiral materials with optical device platforms remains acute14-16. Here we report a simple yet powerful method to fabricate chiroptical flexible layers via supramolecular helical ordering of conjugated polymer chains. Their multiscale chirality and optical activity can be varied across the broad spectral range by chiral templating with volatile enantiomers. After template removal, chromophores remain stacked in one-dimensional helical nanofibrils producing a homogeneous chiroptical layer with drastically enhanced polarization-dependent absorbance, leading to well-resolved detection and visualization of SAM. This study provides a direct path to scalable realization of on-chip detection of the spin degree of freedom of photons necessary for encoded quantum information processing and high-resolution polarization imaging.

  View details for DOI 10.1038/s41586-023-05877-0

  View details for Web of Science ID 000982019500013

  View details for PubMedID 37138111

  View details for PubMedCentralID 7545405

• Surface Doping Effect on the Optoelectronic Properties of Tetrachloro-Substituted Chiral Perylene Diimide Supramolecular Nanowires CHEMISTRY OF MATERIALS Song, I., Shang, X., Ahn, J., Lee, J., Choi, W., Ohtsu, H., Kim, J., Kwak, S., Oh, J. 2022; 34 (19): 8675-8683

  View details for DOI 10.1021/acs.chemmater.2c01684

  View details for Web of Science ID 000862240800001

• Micro-/nano-sized multifunctional heterochiral metal-organic frameworks for high-performance visible-blind UV photodetectors JOURNAL OF MATERIALS CHEMISTRY C Shang, X., Song, I., Jung, G., Choi, W., Ohtsu, H., Lee, J., Ahn, J., Koo, J., Kawano, M., Kwak, S., Oh, J. 2021; 9 (23): 7310-7318

  View details for DOI 10.1039/d1tc01333e

  View details for Web of Science ID 000654365000001

• Bay-Substitution Effect of Perylene Diimides on Supramolecular Chirality and Optoelectronic Properties of Their Self-Assembled Nanostructures ACS APPLIED MATERIALS & INTERFACES Shang, X., Ahn, J., Lee, J., Kim, J., Ohtsu, H., Choi, W., Song, I., Kwak, S., Oh, J. 2021; 13 (10): 12278-12285

  Abstract

  One-dimensional (1D) organic chiral supramolecules have received a great deal of attention for their promising applications in chiral recognition systems, chemical sensors, catalysts, and optoelectronics. Compared to modifications at the imide position of a perylene diimide (PDI), few studies have explored bay substitution of chiral PDIs and their self-assemblies into 1D nanomaterials. Herein, we describe the synthesis of three bay-substituted PDIs and explore the effects of bay substitution on supramolecular chirality by examining circular dichroism spectra and the optoelectronic performance of chiral PDI nanomaterials in phototransistors. Among the three fabricated self-assemblies, nanomaterials based on (R)-CN-CPDI-Ph exhibited the highest electron mobility of 0.17 cm2 V-1 s-1, a low threshold voltage of -1 V, and enhanced optoelectronic performance. For example, the photoresponsivity and external quantum efficiency of (R)-CN-CPDI-Ph assemblies were 4-fold higher than those of (R)-2Br-CPDI-Ph and (R)-2F-CPDI-Ph. All three nanomaterials exhibited fast switching speeds compared with previously reported N-substituted PDIs, suggesting that bay substitution can be an effective means of achieving rapid photoswitching. A comprehensive study using density functional theory calculations and crystal analyses revealed that the enhanced optoelectronic performance of (R)-CN-CPDI-Ph nanomaterials is related to the substitution of CN at the bay position of PDI. This minor change provides simultaneous improvements in electron injectability and structural order. Our findings demonstrate that bay substitution can significantly impact the self-assembly, supramolecular chirality, and optoelectronic properties of PDI nanomaterials.

  View details for DOI 10.1021/acsami.0c23138

  View details for Web of Science ID 000630398500073

  View details for PubMedID 33667057

• π-Extended perylene diimide double-heterohelicenes as ambipolar organic semiconductors for broadband circularly polarized light detection NATURE COMMUNICATIONS Zhang, L., Song, I., Ahn, J., Han, M., Linares, M., Surin, M., Zhang, H., Oh, J., Lin, J. 2021; 12 (1): 142

  Abstract

  Despite great challenges, the development of new molecular structures with multiple and even conflicting characteristics are eagerly pursued for exploring advanced applications. To develop high-performance chiral organic semiconducting molecules, a distorted π-system is required for strong coupling with circularly polarized light (CPL), whereas planar π-stacking systems are necessary for high charge-carrier mobility. To address this dilemma, in this work, we introduce a skeleton merging approach through distortion of a perylene diimide (PDI) core with four fused heteroaromatics to form an ortho-π-extended PDI double-[7]heterohelicene. PDI double helicene inherits a high dissymmetry factor from the helicene skeleton, and the extended π-planar system concurrently maintains a high level of charge transport properties. In addition, ortho-π-extension of the PDI skeleton brings about near-infrared (NIR) light absorption and ambipolar charge transport abilities, endowing the corresponding organic phototransistors with high photoresponsivity of 450 and 120 mA W-1 in p- and n-type modes respectively, along with a high external quantum efficiency (89%) under NIR light irradiations. Remarkably, these multiple characteristics enable high-performance broadband CPL detections up to NIR spectral region with chiral organic semiconductors.

  View details for DOI 10.1038/s41467-020-20390-y

  View details for Web of Science ID 000626604800011

  View details for PubMedID 33420007

  View details for PubMedCentralID PMC7794514

• "Majority-Rules" Effect on Supramolecular Chirality and Optoelectronic Properties of Chiral Tetrachloro-Perylene Diimides ADVANCED OPTICAL MATERIALS Shang, X., Song, I., Han, M., Lee, J., Ohtsu, H., Choi, W., Kim, J., Ahn, J., Kwak, S., Oh, J. 2021; 9 (6)

  View details for DOI 10.1002/adom.202001911

  View details for Web of Science ID 000602648100001

• Optoelectronic Property Modulation in Chiral Organic Semiconductor/Polymer Blends ACS APPLIED MATERIALS & INTERFACES Song, I., Ahn, J., Shang, X., Oh, J. 2020; 12 (44): 49926-49934

  Abstract

  Organic phototransistors (OPTs) have been widely used in biomedical sensing, optical communications, and imaging. Charge-trapping effect has been utilized as an effective strategy for enhancing their photoresponsivity by effectively decreasing the dark current. The combination of organic semiconductors (OSCs), especially chiral OSCs, with insulating polymers has rarely been carried out for optoelectronic applications. Here, we fabricated OPTs containing both enantiopure and racemic air-stable n-type perylene diimide derivatives, CPDI-CN2-C6, and insulating biopolymer polylactide (PLA) and evaluated their photoresponsive properties. The PLA-blended systems exhibited greatly enhanced optoelectronic performances owing to the intense charge-trapping effect. Interestingly, the racemic system showed 3 times higher electron mobility and 12 times higher specific detectivity (1.3 × 1013 jones) compared with the enantiopure systems due to the more aggregated morphologies and larger grains, indicating that chiral composition can be used as a tuning parameter in optoelectronic devices. Our systematic study provides a feasible and effective method for producing high-performance n-type OPTs under ambient conditions.

  View details for DOI 10.1021/acsami.0c17211

  View details for Web of Science ID 000589384100061

  View details for PubMedID 33092342

• Surface-Doped Quasi-2D Chiral Organic Single Crystals for Chiroptical Sensing ACS NANO Shang, X., Song, I., Lee, J., Choi, W., Ahn, J., Ohtsu, H., Kim, J., Koo, J., Kwak, S., Oh, J. 2020; 14 (10): 14146-14156

  Abstract

  Chiral organic optoelectronics using circularly polarized light (CPL) as the key element in the photonic signal has recently emerged as a next-generation photonic technology. However, it remains challenging to simultaneously achieve high polarization selectivity and superior optoelectronic performance. Supramolecular two-dimensional (2D) chiral organic single crystals may be good candidates for this purpose due to their defect-free nature, molecular diversity, and morphologies. Here, quasi-2D single crystals of chiral perylene diimides with parallelogram and triangle/hexagon morphologies have been selectively fabricated via self-assembly using different cosolvent systems. These materials exhibit amplified circular dichroism (CD) spectral signals, due to their molecular packing modes and supramolecular chirality. Through molecular surface n-doping using hydrazine, chiral single crystals exhibit electron mobility surpassing 1.0 cm2 V-1 s-1, which is one of the highest among chiral organic semiconductors, and excellent optoelectronic functions. Theoretical calculations reveal that the radical anions formed by n-doping increase the electron affinity and/or reduce the energy gap, thus facilitating electron transport. More importantly, the doped organic chiral crystals selectively discriminate CPL handedness with a high anisotropy factor of photoresponsivity (∼0.12). These results demonstrate that surface-doped quasi-2D chiral organic single crystals are highly promising for chiral optoelectronics.

  View details for DOI 10.1021/acsnano.0c07012

  View details for Web of Science ID 000586793400161

  View details for PubMedID 33120505

• Non-halogenated solution-processed ambipolar plastic transistors based on conjugated polymers prepared by asymmetric donor engineering JOURNAL OF MATERIALS CHEMISTRY C Song, I., Kim, H., Ahn, J., Han, M., Kwon, S., Kim, Y., Oh, J. 2019; 7 (47): 14977-14985

  View details for DOI 10.1039/c9tc04808a

  View details for Web of Science ID 000506890600018

• Tuning the supramolecular chirality and optoelectronic performance of chiral perylene diimide nanowires <i>via</i> <i>N</i>-substituted side chain engineering JOURNAL OF MATERIALS CHEMISTRY C Shang, X., Song, I., Lee, J., Han, M., Kim, J., Ohtsu, H., Ahn, J., Kwak, S., Oh, J. 2019; 7 (28): 8688-8697

  View details for DOI 10.1039/c9tc01597c

  View details for Web of Science ID 000479006800025

• Heterochiral Doped Supramolecular Coordination Networks for High-Performance Optoelectronics ACS APPLIED MATERIALS & INTERFACES Shang, X., Song, I., Lee, J., Cho, W., Ohtsu, H., Jung, G., Ahn, J., Han, M., Koo, J., Kawano, M., Kwak, S., Oh, J. 2019; 11 (22): 20174-20182

  Abstract

  Chiral self-sorting has great potential for constructing new complex structures and determining chirality-dependent properties in multicomponent mixtures. However, it is still of great challenge to achieve high fidelity chiral self-discrimination. Besides, the researches on the coordination polymers or metal-organic frameworks for micro/nanooptoelectronics are still rare due to their low conductivity and difficulty in developing a rapid and simple scale-up synthetic method. Here, heterochiral supramolecular coordination networks (SCNs) were synthesized by the solvothermal reaction of naphthalene diimide enantiomers and cadmium iodide, using the chirality as a synthetic tuning parameter to control the morphologies. Intriguingly, heterochiral micro/nanocrystals exhibited photochromic and photodetecting properties. Furthermore, we also developed a simple and efficient doping method to enhance the conductivity and photoresponsivity of micro/nanocrystals using hydrazine. From experimental and theoretical studies, the mechanism was suggested as follows: the radicals in the singly occupied molecular orbital level of the ligands provide charge carriers that can undergo "through-space" transport between π-π stacked ligands and the electron transfer from adsorbed hydrazine to the SCNs results in reduction of energy gap, leading to increased conductivity. Our findings demonstrate a simple and powerful strategy for implementing coordination networks with redox ligands for micro/nanooptoelectronic applications.

  View details for DOI 10.1021/acsami.9b04653

  View details for Web of Science ID 000470938500056

  View details for PubMedID 31045348

• Chiral self-sorted multifunctional supramolecular biocoordination polymers and their applications in sensors NATURE COMMUNICATIONS Shang, X., Song, I., Jung, G., Choi, W., Ohtsu, H., Lee, J., Koo, J., Liu, B., Ahn, J., Kawano, M., Kwak, S., Oh, J. 2018; 9: 3933

  Abstract

  Chiral supramolecules have great potential for use in chiral recognition, sensing, and catalysis. Particularly, chiral supramolecular biocoordination polymers (SBCPs) provide a versatile platform for characterizing biorelated processes such as chirality transcription. Here, we selectively synthesize homochiral and heterochiral SBCPs, composed of chiral naphthalene diimide ligands and Zn ions, from enantiomeric and mixed R-ligands and S-ligands, respectively. Notably, we find that the chiral self-sorted SBCPs exhibit multifunctional properties, including photochromic, photoluminescent, photoconductive, and chemiresistive characteristics, thus can be used for various sensors. Specifically, these materials can be used for detecting hazardous amine materials due to the electron transfer from the amine to the SBCP surface and for enantioselectively sensing a chiral species naproxen due to the different binding energies with regard to their chirality. These results provide guidelines for the synthesis of chiral SBCPs and demonstrate their versatility and feasibility for use in various sensors covering photoactive, chemiresistive, and chiral sensors.

  View details for DOI 10.1038/s41467-018-06147-8

  View details for Web of Science ID 000445607500004

  View details for PubMedID 30258195

  View details for PubMedCentralID PMC6158292

• High-Performance Visible-Blind UV Phototransistors Based on n-Type Naphthalene Diimide Nanomaterials ACS APPLIED MATERIALS & INTERFACES Song, I., Lee, S., Shang, X., Ahn, J., Jung, H., Jeong, C., Kim, S., Yoon, W., Yung, H., Kwon, O., Oh, J. 2018; 10 (14): 11826-11836

  Abstract

  This study investigates the performance of single-crystalline nanomaterials of wide-band gap naphthalene diimide (NDI) derivatives with methylene-bridged aromatic side chains. Such materials are found to be easily used as high-performance, visible-blind near-UV light detectors. NDI single-crystalline nanoribbons are assembled using a simple solution-based process (without solvent-inclusion problems), which is then applied to organic phototransistors (OPTs). Such OPTs exhibit excellent n-channel transistor characteristics, including an average electron mobility of 1.7 cm2 V-1 s-1, sensitive UV detection properties with a detection limit of ∼1 μW cm-2, millisecond-level responses, and detectivity as high as 1015 Jones, demonstrating the highly sensitive organic visible-blind UV detectors. The high performance of our OPTs originates from the large face-to-face π-π stacking area between the NDI semiconducting cores, which is facilitated by methylene-bridged aromatic side chains. Interestingly, NDI-based nanoribbon OPTs exhibit a distinct visible-blind near-UV detection with an identical detection limit, even under intense visible light illumination (for example, 104 times higher intensity than UV light intensity). Our findings demonstrate that wide-band gap NDI-based nanomaterials are highly promising for developing high-performance visible-blind UV photodetectors. Such photodetectors could potentially be used for various applications including environmental and health-monitoring systems.

  View details for DOI 10.1021/acsami.8b01500

  View details for Web of Science ID 000430156000050

  View details for PubMedID 29560713