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Oxygen reduction reaction (ORR) electrocatalysis is an area of increasing interest for the in‐situ production of H2O2 or the development of energy‐related devices such as hydrogen fuel cells. Although pyrolyzed catalysts still offer the best performances to date with reference to the organic‐based catalysts, metal‐free and non‐pyrolyzed covalent organic frameworks (COFs) stands out as promising alternatives candidates due to their favourable characteristics such as crystallinity, porosity, and organic composition, allowing the study of structural‐property relationships. Herein, we present the design principles and recent advances in COFs‐based ORR electrocatalysts, demonstrating how composition influences the activity and electronic pathway of the oxygen reduction process. [ABSTRACT FROM AUTHOR]

In the field of organic solar cells, organic semiconductors with Y6‐based chemical structure and their corresponding quinoxaline‐based assemblies are settled down as promising materials in the field of OSCs. However, the chemical structure of Y6 derivatives does not allow an expansion in the electron‐withdrawing central core, in contrast to their quinoxaline‐based analogues. For this reason, herein, two different quinoxaline‐based A–D–A′–D–A derivatives with 2D π‐extended cores endowed with electroactive rylenimide moieties, named as Y6‐1Napht and Y6‐1Pery, are designed and synthesized. These enlarged fused‐ring electron acceptors (FREAs) allow to study the influence of the length of the ryleneimide moiety on its structural, optical, electrochemical, and thermal properties as well as the tailoring of the frontier molecular orbitals. These results are also supported by quantum chemical calculations and photoluminescence measurements that provide additional information about their thermal stability and the microstructure of the films. Finally, as a proof of concept and to study the influence of these chemical modifications on the central core, solar cells based on these π‐conjugated nonfullerene acceptors are fabricated. [ABSTRACT FROM AUTHOR]

The assessment of the photoconductivity of Donor-Acceptor (D-A) ordered bulk heterojunctions is gaining attention for the development of innovative organic semiconductors in optoelectronics. Here, the synthesis of pyrene-based (D) Covalent Organic Frameworks, achieve through a multivariate reaction involving two distinct acceptors is reported (A). The products are characterized using powder x-ray diffraction, N 2 sorption isotherms, electronic microscopy, and in silico calculations, among other techniques. These characterizations reveal that the multicomponent synthesis enables the modification of properties (e.g., bandgap) of the framework while preserving its structural features, such as crystallinity and porosity. The ordered D-A arrays position these materials as promising candidates for photoconductive semiconductors, particularly regarding the variation in the composition of isotopological frameworks. Photoconductivity experiments demonstrate a volcano-type correlation with respect to the A moiety content, with the optimal value reaching 7.9 × 10 -5 cm 2 V -1 s -1 for the bare NIP 25% -COF. This study illustrates how introducing diverse acceptor units through multivariate synthesis can enhance the photoconductivity of these materials via "defect" engineering, without sacrificing their crystalline or porous characteristics and avoiding the need for de novo synthesis., (© 2024 The Author(s). Small published by Wiley‐VCH GmbH.)