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Verma A, Jackson NE. Assessing molecular doping efficiency in organic semiconductors with reactive Monte Carlo. J Chem Phys 2024; 160:104106. [PMID: 38465678 DOI: 10.1063/5.0197816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Accepted: 02/22/2024] [Indexed: 03/12/2024] Open
Abstract
The addition of molecular dopants into organic semiconductors (OSCs) is a ubiquitous augmentation strategy to enhance the electrical conductivity of OSCs. Although the importance of optimizing OSC-dopant interactions is well-recognized, chemically generalizable structure-function relationships are difficult to extract due to the sensitivity and dependence of doping efficiency on chemistry, processing conditions, and morphology. Computational modeling for an integrated OSC-dopant design is an attractive approach to systematically isolate fundamental relationships, but requires the challenging simultaneous treatment of molecular reactivity and morphology evolution. We present the first computational study to couple molecular reactivity with morphology evolution in a molecularly doped OSC. Reactive Monte Carlo is employed to examine the evolution of OSC-dopant morphologies and doping efficiency with respect to dielectric, the thermodynamic driving for the doping reaction, and dopant aggregation. We observe that for well-mixed systems with experimentally relevant dielectric constants, doping efficiency is near unity with a very weak dependence on the ionization potential and electron affinity of OSC and dopant, respectively. At experimental dielectric constants, reaction-induced aggregation is observed, corresponding to the well-known insolubility of solution-doped materials. Simulations are qualitatively consistent with a number of experimental studies showing a decrease of doping efficiency with increasing dopant concentration. Finally, we observe that the aggregation of dopants lowers doping efficiency and thus presents a rational design strategy for maximizing doping efficiency in molecularly doped OSCs. This work represents an important first step toward the systematic integration of molecular reactivity and morphology evolution into the characterization of multi-scale structure-function relationships in molecularly doped OSCs.
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Affiliation(s)
- Archana Verma
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Nicholas E Jackson
- Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, USA
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Le CV, Yoon H. Advances in the Use of Conducting Polymers for Healthcare Monitoring. Int J Mol Sci 2024; 25:1564. [PMID: 38338846 PMCID: PMC10855550 DOI: 10.3390/ijms25031564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/21/2024] [Accepted: 01/22/2024] [Indexed: 02/12/2024] Open
Abstract
Conducting polymers (CPs) are an innovative class of materials recognized for their high flexibility and biocompatibility, making them an ideal choice for health monitoring applications that require flexibility. They are active in their design. Advances in fabrication technology allow the incorporation of CPs at various levels, by combining diverse CPs monomers with metal particles, 2D materials, carbon nanomaterials, and copolymers through the process of polymerization and mixing. This method produces materials with unique physicochemical properties and is highly customizable. In particular, the development of CPs with expanded surface area and high conductivity has significantly improved the performance of the sensors, providing high sensitivity and flexibility and expanding the range of available options. However, due to the morphological diversity of new materials and thus the variety of characteristics that can be synthesized by combining CPs and other types of functionalities, choosing the right combination for a sensor application is difficult but becomes important. This review focuses on classifying the role of CP and highlights recent advances in sensor design, especially in the field of healthcare monitoring. It also synthesizes the sensing mechanisms and evaluates the performance of CPs on electrochemical surfaces and in the sensor design. Furthermore, the applications that can be revolutionized by CPs will be discussed in detail.
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Affiliation(s)
- Cuong Van Le
- School of Polymer Science and Engineering, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea;
- Department of Polymer Engineering, Graduate School, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea
| | - Hyeonseok Yoon
- School of Polymer Science and Engineering, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea;
- Department of Polymer Engineering, Graduate School, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea
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Gilhooly-Finn PA, Jacobs IE, Bardagot O, Zaffar Y, Lemaire A, Guchait S, Zhang L, Freeley M, Neal W, Richard F, Palma M, Banerji N, Sirringhaus H, Brinkmann M, Nielsen CB. Interplay between Side Chain Density and Polymer Alignment: Two Competing Strategies for Enhancing the Thermoelectric Performance of P3HT Analogues. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2023; 35:9029-9039. [PMID: 38027547 PMCID: PMC10653083 DOI: 10.1021/acs.chemmater.3c01680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 10/06/2023] [Indexed: 12/01/2023]
Abstract
A series of polythiophenes with varying side chain density was synthesized, and their electrical and thermoelectric properties were investigated. Aligned and non-aligned thin films of the polymers were characterized in the neutral and chemically doped states. Optical and diffraction measurements revealed an overall lower order in the thin films with lower side chain density, also confirmed using polarized optical experiments on aligned thin films. However, upon doping the non-aligned films, a sixfold increase in electrical conductivity was observed for the polythiophene with the lowest side chain density compared to poly(3-hexylthiophene) (P3HT). We found that the improvement in conductivity was not due to a larger charge carrier density but an increase in charge carrier mobility after doping with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ). On the other hand, doped aligned films did not show the same trend; lower side chain density instead led to a lower conductivity and Seebeck coefficient compared to those for P3HT. This was attributed to the poorer alignment of the polymer thin films with lower side chain density. The study demonstrates that optimizing side chain density is a synthetically simple and effective way to improve electrical conductivity in polythiophene films relevant to thermoelectric applications.
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Affiliation(s)
- Peter A. Gilhooly-Finn
- Department
of Chemistry, University College London, Gower Street, London WC1E 6BT, U.K.
- Department
of Chemistry, Queen Mary University of London, Mile End Road, London E1 4NS, U.K.
| | - Ian E. Jacobs
- Optoelectronics
Group, University of Cambridge, Cavendish
Laboratory, J J Thomson Avenue, Cambridge CB3 0HE, U.K.
| | - Olivier Bardagot
- Department
of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Yasser Zaffar
- Department
of Chemistry, Queen Mary University of London, Mile End Road, London E1 4NS, U.K.
| | - Antoine Lemaire
- Charles
Sadron Institute (ICS), CNRS Université de Strasbourg, UPR
22, 23 Rue du Loess, Strasbourg Cedex 02, 67034, France
| | - Shubhradip Guchait
- Charles
Sadron Institute (ICS), CNRS Université de Strasbourg, UPR
22, 23 Rue du Loess, Strasbourg Cedex 02, 67034, France
| | - Lu Zhang
- Optoelectronics
Group, University of Cambridge, Cavendish
Laboratory, J J Thomson Avenue, Cambridge CB3 0HE, U.K.
| | - Mark Freeley
- Department
of Chemistry, Queen Mary University of London, Mile End Road, London E1 4NS, U.K.
| | - William Neal
- Department
of Chemistry, Queen Mary University of London, Mile End Road, London E1 4NS, U.K.
| | - Fanny Richard
- Université
de Strasbourg, CNRS, ISIS UMR 7006, Strasbourg 67000, France
| | - Matteo Palma
- Department
of Chemistry, Queen Mary University of London, Mile End Road, London E1 4NS, U.K.
| | - Natalie Banerji
- Department
of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Henning Sirringhaus
- Optoelectronics
Group, University of Cambridge, Cavendish
Laboratory, J J Thomson Avenue, Cambridge CB3 0HE, U.K.
| | - Martin Brinkmann
- Charles
Sadron Institute (ICS), CNRS Université de Strasbourg, UPR
22, 23 Rue du Loess, Strasbourg Cedex 02, 67034, France
| | - Christian B. Nielsen
- Department
of Chemistry, Queen Mary University of London, Mile End Road, London E1 4NS, U.K.
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Dixon AL, Vezin H, Nguyen TQ, Reddy GNM. Structural insights into Lewis acid- and F4TCNQ-doped conjugated polymers by solid-state magnetic resonance spectroscopy. MATERIALS HORIZONS 2022; 9:981-990. [PMID: 34982809 DOI: 10.1039/d1mh01574e] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Molecular doping strategies facilitate orders of magnitude enhancement in the charge carrier mobility of organic semiconductors (OSCs). Understanding the different doping mechanisms and molecular-level constraints on doping efficiency related to the material energy levels is crucial to develop versatile dopants for OSCs. Given the compositional and structural heterogeneities associated with OSC thin films, insight into dopant-polymer interactions by long-range techniques such as X-ray scattering and electron microscopy is exceedingly challenging to obtain. This study employs short-range probes, solid-state (ss)NMR and EPR spectroscopy, to resolve local structures and intermolecular interactions between dopants such as F4TCNQ (2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane), Lewis acid BCF (tris[pentafluorophenyl] borane) and Lewis base conjugated polymer, PCPDTBT (P4) (poly[2,6-(4,4-bis(2-hexadecyl)-4H-cyclopenta[2,1-b;3,4-b']dithiophene)-alt-4,7(2,1,3-benzothiadiazole)]). Analysis of 1H and 13C ssNMR spectra of P4, P4 : F4TCNQ and P4 : BCF blends indicates that the addition of dopants induces local structural changes in the P4 polymer, and causes paramagnetism-induced signal broadening and intensity losses. The hyperfine interactions in P4 : BCF and P4 : F4TCNQ are characterized by two-dimensional pulsed EPR spectroscopy. For P4 : F4TCNQ, 19F ssNMR analysis indicates that the F4TCNQ molecules are distributed and aggregated into different local chemical environments. By comparison, BCF molecules are intermixed with the P4 polymer and interact with traces of water molecules to form BCF-water complexes that serve as Brønsted acid sites, as revealed by 11B ssNMR spectroscopy. These results indicate that the P4-dopant blends exhibit complex morphology with different distributions of dopants, whereby the combined use of ssNMR and EPR provides essential insights into how higher doping efficiency is observed with BCF and a mediocre efficiency is associated with F4TCNQ molecules.
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Affiliation(s)
- Alana L Dixon
- Center for Polymers and Organic Solids, University of California Santa Barbara (UCSB), Santa Barbara, California 93106, USA.
| | - Hervé Vezin
- University of Lille, CNRS UMR8516, LASIRE, Lille, F-59000, France
| | - Thuc-Quyen Nguyen
- Center for Polymers and Organic Solids, University of California Santa Barbara (UCSB), Santa Barbara, California 93106, USA.
| | - G N Manjunatha Reddy
- University of Lille, CNRS, Centrale Lille Institut, Univ. Artois, UMR 8181-UCCS-Unité de Catalyse et Chimie du Solide, Lille, F-59000, France.
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