Olefin-linked covalent organic frameworks (OL-COFs) show great promise for visible-light-driven photocatalysis. Manipulating atomic-level donor-acceptor interactions in OL-COFs is key to understanding their exciton effects in this system. Here, three OL-COFs are presented with orthorhombic lattice structures, synthesized via Knoevenagel polycondensation reaction of terephthalaldehyde and tetratopic monomers featuring phenyl, benzo[c][1,2,5]oxadiazole, and benzo[c][1,2,5]thiadiazole moieties. These OL-COFs feature tunable donor-acceptor interactions, making them ideal for studying exciton effects in olefin-linked systems. Comprehensive analyses, including temperature-dependent photoluminescence spectra, ultrafast spectroscopy, and theoretical calculations, reveal that stronger donor-acceptor interactions lead to reduced exciton binding energy (E), accelerated exciton dissociation, and longer-lived photogenerated charges, thereby enhancing photocatalytic performance. Notably, The TMO-BDA COF, with the lowest E, demonstrates superior photocatalytic activity in one-pot sequential organic transformation and excellent catalytic performance in gram-scale reactions, highlighting its potential for practical applications. This work provides valuable insights into regulating the exciton effect at the molecular level in OL-COFs, offering pathways to enhance photocatalytic efficiency.
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http://dx.doi.org/10.1002/smll.202408324 | DOI Listing |
ACS Nano
January 2025
MIIT Key Laboratory of Advanced Display Materials and Devices, Jiangsu Province Engineering Research Center of Quantum Dot Display, School of Materials Science and Engineering, Institute of Optoelectronics & Nanomaterials, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094, China.
Room temperature (RT) synthesized mixed bromine and chlorine CsPbBrCl perovskite quantum dots (Pe-QDs) offer notable advantages for blue quantum dot light-emitting diodes (QLEDs), such as cost-effective processing and narrow luminescence peaks. However, the efficiency of blue QLEDs using these RT-synthesized QDs has been limited by inferior crystallinity and deep defect presence. In this study, we demonstrate a precise approach to constructing high-quality gradient core-shell (CS) structures of CsPbBrCl QD through anion exchange.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
The Organic Photonics and Electronics Group, Department of Physics, Umeå University, SE-90187 Umeå, Sweden.
Light-emitting electrochemical cells (LECs) are promising candidates for fully solution-processed lighting applications because they can comprise a single active-material layer and air-stable electrodes. While their performance is often claimed to be independent of the electrode material selection due to the in situ formation of electric double layers (EDLs), we demonstrate conceptually and experimentally that this understanding needs to be modified. Specifically, the exciton generation zone is observed to be affected by the electrode work function.
View Article and Find Full Text PDFNanomaterials (Basel)
January 2025
Department of Physics, Kyung Hee University, Seoul 02447, Republic of Korea.
We report the complex dielectric function = + of MoS/WS and WS/MoS heterostructures and their constituent monolayers MoS and WS for an energy range from 1.5 to 6.0 eV and temperatures from 39 to 300 K.
View Article and Find Full Text PDFACS Nano
January 2025
Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos 13566-590, Brazil.
Monolayers of transition-metal dichalcogenides, such as MoS, have attracted significant attention for their exceptional electronic and optical properties, positioning them as ideal candidates for advanced optoelectronic applications. Despite their strong excitonic effects, the atomic-scale thickness of these materials limits their light absorption efficiency, necessitating innovative strategies to enhance light-matter interactions. Plasmonic nanostructures offer a promising solution to overcome those challenges by amplifying the electromagnetic field and also introducing other mechanisms, such as hot electron injection.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China.
The introduction of structural defects can improve the charge separation efficiency of metal-organic frameworks (MOFs)-based photocatalysts, which however come with suboptimal decontamination performance, due to steric hindrance and limited binding capacity of the involved modulators. In this work, hydroxyl group capturing the advantages of both worlds was utilized as new modulator to improve the photocatalytic performance of Fe-based defective MOFs. Benefited from its low steric effect and strong coordination bonding capability, hydroxyl-induced defects in Fe-MOF contributed to a nearly 8-fold increase of rate constant for the photocatalytic removal of hexavalent chromium (Cr(VI)) compared to that of pristine one, which also exceeded the defective one induced by acetic acid as modulator.
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