Degradation Behavior of Donor‐acceptor Cyanoarenes‐based Organic Photocatalysts

Ko, Haye Min; Lee, Chung Whan; Kwon, Min Sang

doi:10.1002/cctc.202300661

Cited by 10 publications

(3 citation statements)

References 46 publications

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“…Interestingly, as compared to 4Cz-IPN, 4DP-IPN not only exhibited a longer triplet lifetime but also demonstrated superior T 1 generation (Fig. 3b ) 33 , which facilitate the reactive radical generation in the polymerization through the fast rate of ET process 52 – 55 . To fully leverage the excited-state reducing power of 4DP-IPN and maximize ET, we selected an electron-deficient co-initiator, an iodonium salt (i.e., HNu 254) 56 – 58 .…”

Section: Resultsmentioning

confidence: 98%

Ultraviolet light blocking optically clear adhesives for foldable displays via highly efficient visible-light curing

Kwon,

Lee,

Kim

et al. 2024

Nat Commun

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In developing an organic light-emitting diode (OLED) panel for a foldable smartphone (specifically, a color filter on encapsulation) aimed at reducing power consumption, the use of a new optically clear adhesive (OCA) that blocks UV light was crucial. However, the incorporation of a UV-blocking agent within the OCA presented a challenge, as it restricted the traditional UV-curing methods commonly used in the manufacturing process. Although a visible-light curing technique for producing UV-blocking OCA was proposed, its slow curing speed posed a barrier to commercialization. Our study introduces a highly efficient photo-initiating system (PIS) for the rapid production of UV-blocking OCAs utilizing visible light. We have carefully selected the photocatalyst (PC) to minimize electron and energy transfer to UV-blocking agents and have chosen co-initiators that allow for faster electron transfer and more rapid PC regeneration compared to previously established amine-based co-initiators. This advancement enabled a tenfold increase in the production speed of UV-blocking OCAs, while maintaining their essential protective, transparent, and flexible properties. When applied to OLED devices, this OCA demonstrated UV protection, suggesting its potential for broader application in the safeguarding of various smart devices.

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Section: Resultsmentioning

confidence: 98%

Ultraviolet light blocking optically clear adhesives for foldable displays via highly efficient visible-light curing

Kwon,

Lee,

Kim

et al. 2024

Nat Commun

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“…In situ synthesis of a heptablock P(MA) 7 polymer was achieved by continuously adding monomer and solvent without additional PC 5 (Figure S38). To further verify the robustness of PC 5 , its photodegradation behavior under blue light irradiation was monitored in situ by thin-layer chromatography (TLC). ,, Regardless of the presence of the RAFT agent BTPA, no photodegradation of PC 5 was detected after 4 h of exposure to blue light (Figure S39). The presence of the carboxyl group (−COOH) in BTPA resulted in some chromatographic tailing during the TLC monitoring.…”

Section: Resultsmentioning

confidence: 99%

Pyrazino[2,3-f][1,10]phenanthroline Derivatives as Robust Photocatalysts Enabling ppm-Level Organocatalyzed Photoinduced Electron/Energy Transfer Reversible Addition–Fragmentation Chain Transfer Polymerization

Hu,

Gao,

Shi

et al. 2024

ACS Catal.

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Exploring high-performance organic photocatalysts (PCs) for photoinduced electron/energy transfer reversible addition− fragmentation chain transfer (PET-RAFT) polymerization represents a cutting-edge research field. In this study, six donor (D)−acceptor (A) type organic PCs based on the pyrazino[2,3-f ][1,10]phenanthroline structure were designed and synthesized, showcasing their successful application in PET-RAFT polymerization. Furthermore, diverse substituent groups were introduced to enable precise control over the photophysical and electrochemical properties of organic PCs. Timedependent density functional theory (TD-DFT) analysis further identified two organic PCs (PCs 5 and 6) that exhibit thermally activated delayed fluorescence (TADF) characteristics. PCs 5 and 6 demonstrated high molar extinction coefficients (ε max ) and long delayed fluorescence (DF) lifetimes, achieving high-efficiency photopolymerization even at catalyst loadings as low as 0.1−10 ppm. This study elucidates the structure−activity correlation of such organic PCs while underscoring the facile construction of efficient PCs with TADF characteristics through strategic structural design. These findings serve as a valuable reference for advancing the development of high-performance organic PCs capable of lightinduced reversible-deactivation radical polymerization (RDRP).

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“…3 a and 4a . It have been previously reported that the degradation of cyanoarene PCs can occur via (i) a substitution of the −CN group with alkyl radicals 68 , 93 , and (ii) a self-degradation upon the photoexcitation, such as a intramolecular cyclization 94 or chemical bond-cleavages 95 . In our reaction, given the very low radical concentration controlled by the ATRP equilibrium, their reactivities with the PC species (i.e., PC •– or PC •+ ) are likely suppressed.…”

Section: Resultsmentioning

confidence: 99%

Highly efficient dual photoredox/copper catalyzed atom transfer radical polymerization achieved through mechanism-driven photocatalyst design

Jeon,

Kwon,

Kwon

2024

Nat Commun

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Atom transfer radical polymerization (ATRP) with dual photoredox/copper catalysis combines the advantages of photo-ATRP and photoredox-mediated ATRP, utilizing visible light and ensuring broad monomer scope and solvent compatibility while minimizing side reactions. Despite its popularity, challenges include high photocatalyst (PC) loadings (10 to 1000 ppm), requiring additional purification and increasing costs. In this study, we discover a PC that functions at the sub-ppm level for ATRP through mechanism-driven PC design. Through studying polymerization mechanisms, we find that the efficient polymerizations are driven by PCs whose ground state oxidation potential—responsible for PC regeneration—play a more important role than their excited state reducing power, responsible for initiation. This is verified by screening PCs with varying redox potentials and triplet excited state generation capabilities. Based on these findings, we identify a highly efficient PC, 4DCDP-IPN, featuring moderate excited state reducing power and a maximized ground state oxidation potential. Employing this PC at 50 ppb, we synthesize poly(methyl methacrylate) with high conversion, narrow molecular weight distribution, and high chain-end fidelity. This system exhibits oxygen tolerance and supports large-scale reactions under ambient conditions. Our findings, driven by the systematic PC design, offer meaningful insights for controlled radical polymerizations and metallaphotoredox-mediated syntheses beyond ATRP.

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Degradation Behavior of Donor‐acceptor Cyanoarenes‐based Organic Photocatalysts

Cited by 10 publications

References 46 publications

Ultraviolet light blocking optically clear adhesives for foldable displays via highly efficient visible-light curing

Ultraviolet light blocking optically clear adhesives for foldable displays via highly efficient visible-light curing

Pyrazino[2,3-f][1,10]phenanthroline Derivatives as Robust Photocatalysts Enabling ppm-Level Organocatalyzed Photoinduced Electron/Energy Transfer Reversible Addition–Fragmentation Chain Transfer Polymerization

Highly efficient dual photoredox/copper catalyzed atom transfer radical polymerization achieved through mechanism-driven photocatalyst design

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