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A Photoconductive Thienothiophene-based Covalent Organic Framework Showing Charge Transfer Towards Included Fullerene.

Mirjam Dogru, M. Handloser, F. Auras, T. Kunz, D. Medina, A. Hartschuh, P. Knochel, T. Bein
Published 2013 · Medicine

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Organic bulk heterojunctions combining electron donor and acceptor phases are of great interest for designing organic photovoltaic devices. While impressive advances have been achieved with these systems, so far a deterministic control of their nanoscale morphology has been elusive. It would be a major breakthrough to be able to create model systems with periodic, interpenetrating networks of electron donor and acceptor phases providing maximum control over all structural and electronic features. Herein we report a significant step towards this goal on the basis of the recently discovered class of crystalline covalent organic frameworks (COFs) which are created by condensation of molecular building blocks. Specifically, the stacked layers of two-dimensional COFs permit charge migration through the framework, and several semiconducting structures with high carrier mobilities have been described. We have created a COF containing stacked thieno[2,3-b]thiophene-based building blocks serving as electron donors (TT-COF), with high surface area and a 3 nm open pore system. This open framework takes up the wellknown fullerene electron acceptor [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), thus forming a novel structurally ordered donor–acceptor network. Spectroscopic results demonstrate light-induced charge transfer from the photoconductive TT-COF donor network to the encapsulated PCBM phase in the pore system. Moreover, we have created the first working COF-based photovoltaic device with the above components. The organization of the molecular building blocks into a crystalline framework with defined conduction paths provides a promising model system for ordered and interpenetrated networks of donors and acceptors at the nanoscale. The most prominent hole-conducting material used in organic solar cells is poly(3-hexylthiophene) (P3HT), a thiophene-containing polymer with high charge-carrier mobilities. The soluble fullerene derivative PCBM is often used as an electron acceptor in organic photovoltaics. Because of the lack of structural order in the respective bulk heterojunctions it is very difficult to assess the impact of molecular building blocks, bonding motifs, and energy levels on the microscopic processes involving light-induced exciton formation, charge separation, and transport in such systems. Hence ordered charge-transporting networks with a periodicity of several nanometers are of great interest to understand the mechanistic details of the light-induced processes and ultimately to obtain design rules for the creation of efficient and stable organic photovoltaic devices. The new TT-COF was synthesized under solvothermal conditions by co-condensation of thieno[3,2-b]thiophene-2,5diyldiboronic acid (TTBA) and the polyol 2,3,6,7,10,11hexahydroxytriphenylene (HHTP; Figure 1a). Reaction parameters are described in the Supporting Information. As described in the following, the thienothiophene-based COF forms stacks in an AA arrangement, as confirmed by N2 sorption and powder X-ray diffraction. Powder X-ray diffraction (PXRD) confirms the formation of a highly crystalline COF. Identification of the new structure was conducted by comparison of structures modeled with MS Studio (see Figures S1–S5 in the Supporting Information). Corresponding powder patterns were simulated and compared to the experimentally obtained data. For previous COF structures different stacking types of the hexagonal planar sheets were reported. Hence calculations were carried out simulating an eclipsed AA arrangement and a staggered AB arrangement. The experimental PXRD pattern for TT-COF agrees very well with the simulated pattern for an eclipsed AA arrangement (Figure 1b) with a hexagonal P6m symmetry. Moreover, unit-cell parameters determined from the experimental X-ray patterns match very well with those obtained from the structure simulations (peak broadening included). FT-IR spectroscopy can confirm the presence of the newly formed boronate ester functionality. As previously reported, the attenuation of the OH stretching band resulting from the ester formation is apparent, and furthermore the most characteristic modes of the C-B and C-O functionalities can be assigned to the bands at 1395 cm 1 and 1353 cm 1 (see Figure S8 in the Supporting Information). The B MAS NMR spectrum (see Figure S9 in the Supporting Information) shows a trigonal-planar boron atom with a chemical shift of d= 21 ppm, which can be distinguished from the starting material (TTBA: d= 15 ppm). Transmission electron microscopy (TEM) images show the nanoscale morphology of the crystals. A slightly tilted side view shows the long ordered channels with distinct pore sizes (see Figure S12 in the Supporting Information). A top view [*] Dr. M. Dogru, M. Handloser, F. Auras, Dr. T. Kunz, Dr. D. Medina, Prof. Dr. A. Hartschuh, Prof. Dr. P. Knochel, Prof. Dr. T. Bein Department of Chemistry and Center for NanoScience (CeNS), Ludwig-Maximilians-Universit t Munich (LMU) Butenandtstrase 5–13 (E), 81377 Munich (Germany) E-mail: Homepage:
This paper references
Analytical molecular surface calculation
M. L. Connolly (1983)
Synthesis of metallophthalocyanine covalent organic frameworks that exhibit high carrier mobility and photoconductivity.
Xuesong Ding (2011)
Femtosecond Time-Resolved Fluorescence Study of P3HT/PCBM Blend Films
Y. Xie (2010)
Porous, Crystalline, Covalent Organic Frameworks
A. P. Côté (2005)
Photoinduced Electron Transfer from a Conducting Polymer to Buckminsterfullerene
N. S. Sariciftci (1992)
A photoconductive covalent organic framework: self-condensed arene cubes composed of eclipsed 2D polypyrene sheets for photocurrent generation.
S. Wan (2009)
Development status of high-efficiency HIT solar cells
T. Mishima (2011)
Designed Synthesis of 3D Covalent Organic Frameworks
Hani M El-Kaderi (2007)
Efficiency enhancement in low-bandgap polymer solar cells by processing with alkane dithiols.
J. Peet (2007)
Covalent organic frameworks.
Xiao Feng (2012)
Photoinduced Charge Carrier Generation in Blends of Poly(Thienothiophene) Derivatives and [6,6]-Phenyl-C61-butyric Acid Methyl Ester: Phase Segregation versus Intercalation
T. Savenije (2010)
Molecular Modelling: Principles and Applications
A. Leach (1996)
Polymer Photovoltaic Cells: Enhanced Efficiencies via a Network of Internal Donor-Acceptor Heterojunctions
G. Yu (1995)
Covalent Organic Frameworks with High Charge Carrier Mobility
Shun Wan (2011)
Reticular synthesis of microporous and mesoporous 2D covalent organic frameworks.
A. P. Côté (2007)
Facile Synthesis of a Highly Crystalline, Covalently Linked Porous Boronate Network
R. Tilford (2006)
Lattice expansion of highly oriented 2D phthalocyanine covalent organic framework films.
Eric L. Spitler (2012)
Contactless Determination of the Photoconductivity Action Spectrum, Exciton Diffusion Length, and Charge Separation Efficiency in Polythiophene-Sensitized TiO2 Bilayers
Jessica E. Kroeze (2003)
A 2D covalent organic framework with 4.7-nm pores and insight into its interlayer stacking.
Eric L. Spitler (2011)
An ambipolar conducting covalent organic framework with self-sorted and periodic electron donor-acceptor ordering.
Xiao Feng (2012)
Stable polythiophene semiconductors incorporating thieno[2,3-b]thiophene.
M. Heeney (2005)

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T. Kundu (2018)
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M. Ikai (2014)
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Guo Lin (2017)
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J. Crowe (2016)
Covalent organic frameworks as pH responsive signaling scaffolds.
Yuwei Zhang (2016)
Pd loaded amphiphilic COF as catalyst for multi-fold Heck reactions, C-C couplings and CO oxidation
Dinesh Mullangi (2015)
Conjugated Covalent Organic Frameworks via Michael Addition-Elimination.
M. R. Rao (2017)
Stable Covalent Organic Frameworks for Exceptional Mercury Removal from Aqueous Solutions.
N. Huang (2017)
Pore surface engineering in porous, chemically stable covalent organic frameworks for water adsorption
B. P. Biswal (2015)
Thermally/hydrolytically stable covalent organic frameworks from a rigid macrocyclic host.
Jingru Song (2014)
Discrete, Hexagonal Boronate Ester-Linked Macrocycles Related to Two-Dimensional Covalent Organic Frameworks
A. Chavez (2016)
Synthesis and characterization of a new covalent organic framework linked by NH linkage
Rui Xue (2017)
TD-DFT insights into the sensing potential of the luminescent covalent organic framework for indoor pollutant formaldehyde.
M. Hussain (2019)
Construction of Donor-Acceptor Heterojunctions in Covalent Organic Framework for Enhanced CO2 Electroreduction.
Q. Wu (2020)
Postsynthetic functionalization of covalent organic frameworks
Y. Yusran (2020)
Efficient Removal of Cr(VI) from Aqueous Solutions by a Dual‐Pore Covalent Organic Framework
Fu-Zhi Cui (2019)
Tuning the structure and properties of nitrogen-rich covalent organic frameworks by molecular design and solid state reactions
F. Haase (2018)
Conjugated organic framework with three-dimensionally ordered stable structure and delocalized π clouds
Jia Guo (2013)
Unveiling Electronic Properties in Metal-Phthalocyanine-based Pyrazine-linked Conjugated Two-Dimensional Covalent Organic Frameworks.
M. Wang (2019)
Kovalente organische Gerüstverbindungen: chemische Ansätze für Designerstrukturen und integrierte Funktionen
Xinyi Chen (2020)
Spectroscopy and dynamics of a HOF and its molecular units: remarkable vapor acid sensing
E. Gomez (2019)
Edge Functionalization of Graphene and Two-Dimensional Covalent Organic Polymers for Energy Conversion and Storage.
Z. Xiang (2016)
π-Conjugated Microporous Polymer Films: Designed Synthesis, Conducting Properties, and Photoenergy Conversions
C. Gu (2015)
Synthesis of 2D Covalent Organic Frameworks at the Solid–Vapor Interface
Tianting Chen (2013)
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Kewei Wang (2017)
Microtubular Self‐Assembly of Covalent Organic Frameworks
Bappaditya Gole (2018)
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N. Huang (2015)
Well-defined two dimensional covalent organic polymers: rational design, controlled syntheses, and potential applications
Zhonghua Xiang (2015)
Luminescent Porous Polymers Based on Aggregation-Induced Mechanism: Design, Synthesis and Functions.
Sasanka Dalapati (2016)
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