Thiophene-Bridged Donor–Acceptor sp2-Carbon-Linked 2D Conjugated Polymers as Photocathodes for Water Reduction

Xu S, Sun H, Addicoat M, Biswal BP, He F, Park S, Paasch S, Zhang T, Sheng W, Brunner E, Hou Y, Richter M, Feng X (2021)

Publication Type: Journal article

Publication year: 2021

Journal

Advanced Materials Wiley

Book Volume: 33

Article Number: 2006274

Journal Issue: 1

DOI: 10.1002/adma.202006274

Abstract

Photoelectrochemical (PEC) water reduction, converting solar energy into environmentally friendly hydrogen fuel, requires delicate design and synthesis of semiconductors with appropriate bandgaps, suitable energy levels of the frontier orbitals, and high intrinsic charge mobility. In this work, the synthesis of a novel bithiophene-bridged donor–acceptor-based 2D sp2-carbon-linked conjugated polymer (2D CCP) is demonstrated. The Knoevenagel polymerization between the electron-accepting building block 2,3,8,9,14,15-hexa(4-formylphenyl) diquinoxalino[2,3-a:2′,3′-c]phenazine (HATN-6CHO) and the first electron-donating linker 2,2′-([2,2′-bithiophene]-5,5′-diyl)diacetonitrile (ThDAN) provides the 2D CCP-HATNThDAN (2D CCP-Th). Compared with the corresponding biphenyl-bridged 2D CCP-HATN-BDAN (2D CCP-BD), the bithiophene-based 2D CCP-Th exhibits a wide light-harvesting range (up to 674 nm), a optical energy gap (2.04 eV), and highest energy occupied molecular orbital–lowest unoccupied molecular orbital distributions for facilitated charge transfer, which make 2D CCP-Th a promising candidate for PEC water reduction. As a result, 2D CCP-Th presents a superb H2-evolution photocurrent density up to ≈7.9 µA cm−2 at 0 V versus reversible hydrogen electrode, which is superior to the reported 2D covalent organic frameworks and most carbon nitride materials (0.09–6.0 µA cm−2). Density functional theory calculations identify the thiophene units and cyano substituents at the vinylene linkage as active sites for the evolution of H2.

Involved external institutions

Technische Universität Dresden DE Germany (DE) Zhejiang University CN China (CN) Nottingham Trent University GB United Kingdom (GB) Ashoka University IN India (IN)

How to cite

APA:

Xu, S., Sun, H., Addicoat, M., Biswal, B.P., He, F., Park, S.,... Feng, X. (2021). Thiophene-Bridged Donor–Acceptor sp2-Carbon-Linked 2D Conjugated Polymers as Photocathodes for Water Reduction. Advanced Materials, 33(1). https://doi.org/10.1002/adma.202006274

MLA:

Xu, Shunqi, et al. "Thiophene-Bridged Donor–Acceptor sp2-Carbon-Linked 2D Conjugated Polymers as Photocathodes for Water Reduction." Advanced Materials 33.1 (2021).

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