Electron Transport over 2D Molecular Materials and Assemblies

Accounts of Chemical Research, Journal Year: 2024, Volume and Issue: 57(18), P. 2665 - 2677

Published: Aug. 20, 2024

ConspectusTwo-dimensional (2D) molecular materials, in which the major interactions are confined 2D planes with contrasted force fields acting between planes, have been key electronic functional materials since past decade. Even without referring to functionals of graphene-based systems, conjugated systems expected show extrawide dynamic ranges density states (DOS) tuning, effective electron mass, mobility, and conductivity. A advantage is their compatibility ubiquitous devices designed using planar structures, such as transistors memories, associated utility active materials. The mobility electrons utility, various optimize mobility. This Account begins an introduction for assessment: noncontact time-resolved microwave conductivity (TRMC) measurements a technique probe differential upon transient charge carrier injection into Electronic transport over graphenes, covalent organic frameworks (COFs), metal–organic (MOFs) discussed special emphasis on building blocks, fine-tuning conducting species linkages, topology framework, controlling doping. superiority β-ketoenamine-linked COF imine-linked films dominant in-plane out-of-plane also illustrated. Systematic engineering blocks COFs varying degrees donor–acceptor (D–A) conjugation, torsional angles, reaction conditions resulted modulation efficiency generation/transport well exciton migration. advantages finally terms interplaying spatial arrangements molecules substantial role intermolecular stabilizing condensed phases. strong correlation dispersion hierarchical sheds light way overcome structural fluctuation optimization point singularity at distance d ∼ 0.3 nm deduced from overall assessment phases molecules, suggesting roles coupling: new concept conjugation. Exceptional coupling relatively high was observed, particularly chiral contrast 3D analogues, where reduction gravitational condensates impacting DOS: Wallach's rule. candidates violation long-lasting rule DOS.

Language: Английский

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Regulating the Isomerization Geometry and Energy State of Covalent Organic Frameworks for Enhanced Oxygen Reduction Activity

Advanced Materials, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 19, 2025

Abstract Embedding isomer entities onto crystalline frameworks with precisely defined spatial distributions represents a promising approach to enhancing the efficiency of oxygen reduction reaction (ORR) in fuel cells. However, accurately constructing covalent organic (COFs) regulate energy state effectively remains significant challenge. Herein, an innovative geometric isomerization strategy aimed at minimizing rotational barrier (ΔE), average local ionization (ALIE), and Gibbs free (ΔG) for ORR within COFs is proposed. Based on this strategy, isomeric Py‐COF‐αα 2,2‐substitution, Py‐COF‐ββ 3,3‐substitution, Py‐COF‐αβ 2,3‐substitution mainchain have been obtained. The electronic states intermediate adsorption capabilities are finely tuned through modification, yielding controllable chemical activity. Notably, lower ΔE between thiophenes achieves remarkable performance, evidenced by half‐wave potential 0.77 V vs reversible hydrogen electrode (RHE), surpassing most reported metal‐free electrocatalysts. Combined theoretical prediction situ Raman spectra, it revealed that increased dipole moment non‐uniform charge distribution caused endows pentacyclic‐carbon (thiophene β‐position) far from sulfur atoms efficient catalytic This work has opened up novel paradigm underscores pivotal role regulation facilitating catalysis.

Language: Английский

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Rolling two-dimensional covalent organic framework (COF) sheets into one-dimensional electronic and proton-conductive nanotubes

Proceedings of the National Academy of Sciences, Journal Year: 2025, Volume and Issue: 122(16)

Published: April 16, 2025

Mimicking the interconvertible carbon allotropes of 2-dimensional (2D) graphene and 1-dimensional (1D) nanotubes (CNTs), herein we report in situ transformation 2D π-conjugated covalent organic frameworks (COFs) sheet into 1D nanotubular structures via self-assembly sheets at solvent interfaces. The facile “roll-sheets” resulted coaxial with uniform cross-sectional diameter, which was realized for diazapyrene-based COFs but not corresponding pyrene COF, although both possess similar chemical structures. Upon replacing atoms 2,7-positions nitrogen, contrasting optical electronic properties were realized, reflecting rolled structure conjugated sheets. exhibited concerted electronic- proton-conducting nature stable conducting pathways ambient conditions. nitrogen centers act simultaneously as site charge carrier doping proton acceptors, evidenced by high photo- electrical conductivity, well record conductivity (σ = 1.98 S cm −1 ) results. present COF serves a unique materials platform conduction wall core, respectively.

Language: Английский

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Doping Detection Based on the Nanoscale: Biosensing Mechanisms and Applications of Two-Dimensional Materials

Biosensors, Journal Year: 2025, Volume and Issue: 15(4), P. 227 - 227

Published: April 3, 2025

Doping undermines fairness in sports and threatens athlete health, while conventional detection methods like LC-MS GC-MS face challenges such as complex procedures, matrix interferences, lengthy processing times, limiting on-site applications. Two-dimensional (2D) materials, including graphene, MoS2, metal–organic frameworks (MOFs), offer promising solutions due to their large surface areas, tunable electronic structures, special interactions with doping agents, hydrogen bonding, π-π stacking, electrostatic forces. These materials enable signal transduction through changes conductivity or fluorescence quenching. This review highlights the use of 2D detection. For example, reduced graphene oxide–MOF composites show high sensitivity for detecting anabolic steroids testosterone, NiO/NGO nanocomposites exhibit strong selectivity stimulants ephedrine. However, environmental instability production costs hinder widespread application. Future efforts should focus on improving material stability chemical modifications, reducing costs, integrating these into advanced systems machine learning. Such advancements could revolutionize detection, ensuring protecting health.

Language: Английский

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Cu atom pairs within covalent organic frameworks facilitate the photocatalytic reduction of CO2 to C2H6

Applied Catalysis B Environment and Energy, Journal Year: 2025, Volume and Issue: unknown, P. 125499 - 125499

Published: May 1, 2025

Language: Английский

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Modulating π-bridge in donor-π-acceptor covalent organic frameworks for low-energy-light-driven photocatalytic reaction

Journal of Colloid and Interface Science, Journal Year: 2024, Volume and Issue: 683, P. 612 - 621

Published: Dec. 26, 2024

Language: Английский

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