The generation of a long-lived charge-separated state in versatile π-conjugated two-dimensional covalent organic frameworks (2D COFs), a process essential to extending their great potentials in advanced semiconducting applications, is yet fully elucidated. Herein, we report a systematic investigation of the photophysical properties of three highly crystalline imine-linked 2D COFs using steady-state and transient absorption spectroscopy accompanied by time-dependent density functional theory (TDDFT) calculations. The different electron affinity between 5,5',5″-(1,3,5-benzenetriyl)tris(2-pyridinecarboxaldehyde) (BTPA) and three tunable electron-donating/accepting triamine monomers dominated the formation of the excited-state, charge-transfer direction, and lifetime. A prominent charge transfer from electron-rich 4,4',4″-triaminotriphenylamine (TAPA) to BTPA in COF led to the long-lived charge-separated state, which was attributed to a greater degree of delocalization compared to the two other COFs. These results provide fundamental insight into the importance of structure-property correlation for designing advanced photoactive 2D COF materials with the efficient charge transfer and long-lived charge-separated state.
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http://dx.doi.org/10.1021/acs.jpclett.1c04163 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
The University of Oklahoma, Chemistry and Biochemistry, 101 Stephenson Parkway, 73019, Norman, UNITED STATES OF AMERICA.
Phototherapy - which includes photothermal therapy (PTT) and photodynamic therapy (PDT) - has evoked interest as a promising cancer treatment modality on account of its noninvasiveness, spatiotemporal precision, and minimal side effects. C. Wang et al.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Department of Applied Chemistry, Chuo University, Tokyo 112-8551, Japan.
We employed machine learning (ML) techniques combined with potential-dependent photoelectrochemical impedance spectroscopy (pot-PEIS) to gain deeper insights into the charge transport mechanisms of hematite (α-FeO) photoanodes. By the Shapley Additive exPlanations (SHAP) analysis from the ML model constructed from a small data set (dozens of samples) of electrical parameters obtained from pot-PEIS and the PEC performance, we identified the dominant factors influencing the electron transport to the back contact in the bulk and hole transfer to a solution at the hematite/electrolyte interface. The results revealed that shallow defect states significantly enhance electron transport, while deep defect states impede it, and also one of the surface states enhances the hole transfer to the electrolyte solution.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Ritsumeikan University: Ritsumeikan Daigaku, Applied Chemistry, B805 Biolink, 1-1-1 Nojihigashi, 525-8577, Kusatsu, JAPAN.
Inorganic photochromic materials offer several advantages over organic compounds, including relatively inexpensive and higher thermal stability. However, tuning their color with the same component has remained a significant challenge. In this study, we demonstrate that the photochromic color of Cu-doped ZnS nanocrystals (NCs), which is initially pale yellow before light irradiation, can be tuned from gray to brown by adjusting the surface stoichiometry of Zn and S, which is controlled through the use of thiol and non-thiol ligands.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P.R. China.
Gold nanoclusters (Au NCs) protected by molecular ligands represent a new class of second-generation near-infrared (NIR-II) luminescent materials that have been widely studied. However, the photoluminescence efficiencies of most NIR-II emitting Au NCs in aqueous solution are generally lower than 0.2%, and to fully exploit the advantages of AuNCs in the NIR-II region, improving their photoluminescence efficiency has become an urgent need.
View Article and Find Full Text PDFChem Sci
January 2025
State Key Laboratory of Powder Metallurgy, Central South University Changsha 410083 P. R. China
In overcoming the barrier of rapid Li transfer in lithium-ion batteries at extreme temperatures, the desolvation process and interfacial charge transport play critical roles. However, tuning the solvation structure and designing a kinetically stable electrode-electrolyte interface to achieve high-rate charging and discharging remain a challenge. Here, a lithium nonafluoro-1-butanesulfonate (NFSALi) additive is introduced to optimize stability and the robust solid electrolyte interface film (SEI), realizing a rapid Li transfer process and the structural integrity of electrode materials.
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