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Structural insights into Lewis acid- and F4TCNQ-doped conjugated polymers by solid-state magnetic resonance spectroscopy

Journal Article · · Materials Horizons
DOI:https://doi.org/10.1039/d1mh01574e· OSTI ID:1978807
 [1];  [2];  [3];  [2]
  1. University of California, Santa Barbara, CA (United States); OSTI
  2. University of Lille (France)
  3. University of California, Santa Barbara, CA (United States)

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.

Research Organization:
University of California, Santa Barbara, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC)
Grant/Contract Number:
SC0017659
OSTI ID:
1978807
Journal Information:
Materials Horizons, Journal Name: Materials Horizons Journal Issue: 3 Vol. 9; ISSN 2051-6347
Publisher:
Royal Society of ChemistryCopyright Statement
Country of Publication:
United States
Language:
English

References (66)

Electronic Processes in Organic Semiconductors: An Introduction book March 2015
The Effects of Crystallinity on Charge Transport and the Structure of Sequentially Processed F 4 TCNQ-Doped Conjugated Polymer Films journal September 2017
Unifying Energetic Disorder from Charge Transport and Band Bending in Organic Semiconductors journal March 2019
Localized Charge Transfer in a Molecularly Doped Conducting Polymer journal September 2007
Direct Observation of Doping Sites in Temperature-Controlled, p-Doped P3HT Thin Films by Conducting Atomic Force Microscopy journal July 2014
Band-Like Electron Transport with Record-High Mobility in the TCNQ Family journal March 2015
Understanding the High Performance of over 15% Efficiency in Single‐Junction Bulk Heterojunction Organic Solar Cells journal October 2019
p-Type Doping of Poly(3-hexylthiophene) with the Strong Lewis Acid Tris(pentafluorophenyl)borane journal September 2016
Brønsted Acid Doping of P3HT with Largely Soluble Tris(pentafluorophenyl)borane for Highly Conductive and Stable Organic Thermoelectrics Via One‐Step Solution Mixing journal October 2020
Doped organic semiconductors: Physics and application in light emitting diodes journal September 2003
The chemical and structural origin of efficient p-type doping in P3HT journal May 2013
Controllable molecular doping in organic single crystals toward high-efficiency light-emitting devices journal April 2021
Probing proton–proton proximities in the solid state journal July 2007
Applications of high-resolution 1H solid-state NMR journal February 2012
Imaging of morphological changes and phase segregation in doped polymeric semiconductors journal January 2015
Molecular Electrical Doping of Organic Semiconductors: Fundamental Mechanisms and Emerging Dopant Design Rules journal February 2016
Determining the Crystal Structures of Peptide Analogs of Boronic Acid in the Absence of Single Crystals: Intricate Motifs of Ixazomib Citrate Revealed by XRPD Guided by ss-NMR journal April 2018
Introducing Solubility Control for Improved Organic P-Type Dopants journal August 2015
Doping of Large Ionization Potential Indenopyrazine Polymers via Lewis Acid Complexation with Tris(pentafluorophenyl)borane: A Simple Method for Improving the Performance of Organic Thin-Film Transistors journal October 2016
Thermoelectric Properties of Poly(3-hexylthiophene) (P3HT) Doped with 2,3,5,6-Tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F 4 TCNQ) by Vapor-Phase Infiltration journal January 2018
Atomic-Level Insight into the Postsynthesis Band Gap Engineering of a Lewis Base Polymer Using Lewis Acid Tris(pentafluorophenyl)borane journal December 2018
Stability of Charge Transfer States in F 4 TCNQ-Doped P3HT journal December 2018
Doped Organic Transistors journal October 2016
Quantitative Analysis of Doping-Induced Polarons and Charge-Transfer Complexes of Poly(3-hexylthiophene) in Solution journal June 2020
Unraveling the Microstructure of Molecularly Doped Poly(3-hexylthiophene) by Thermally Induced Dedoping journal October 2018
Evaporation vs Solution Sequential Doping of Conjugated Polymers: F 4 TCNQ Doping of Micrometer-Thick P3HT Films for Thermoelectrics journal August 2019
Molecular Doping of PCPDT–BT Copolymers: Comparison of Molecular Complexes with and without Integer Charge Transfer journal December 2019
Overcoming Film Quality Issues for Conjugated Polymers Doped with F 4 TCNQ by Solution Sequential Processing: Hall Effect, Structural, and Optical Measurements journal November 2015
Macroscopic Structural Compositions of π-Conjugated Polymers: Combined Insights from Solid-State NMR and Molecular Dynamics Simulations journal August 2017
Enhanced Electrical Conductivity of Molecularly p-Doped Poly(3-hexylthiophene) through Understanding the Correlation with Solid-State Order journal October 2017
Closing the Stability–Performance Gap in Organic Thermoelectrics by Adjusting the Partial to Integer Charge Transfer Ratio journal January 2020
Control of Chain Alignment and Crystallization Helps Enhance Charge Conductivities and Thermoelectric Power Factors in Sequentially Doped P3HT:F 4 TCNQ Films journal March 2020
In Situ Synthesis of Trifluoroacetic Acid-Doped Polyaniline/Reduced Graphene Oxide Composites for High-Performance All-Solid-State Supercapacitors journal August 2020
Cooperative Self-Assembly Driven by Multiple Noncovalent Interactions: Investigating Molecular Origin and Reassessing Characterization journal July 2021
Highly Efficient Organic Devices Based on Electrically Doped Transport Layers journal April 2007
Advanced Solid-State NMR Methods for the Elucidation of Structure and Dynamics of Molecular, Macromolecular, and Supramolecular Systems journal December 2001
Aqua, Alcohol, and Acetonitrile Adducts of Tris(perfluorophenyl)borane:  Evaluation of Brønsted Acidity and Ligand Lability with Experimental and Computational Methods journal November 2000
Direct Observation of the Relationship between Molecular Topology and Bulk Morphology for a π-Conjugated Material journal February 2019
Molecular Interactions and Ordering in Electrically Doped Polymers: Blends of PBTTT and F 4 TCNQ journal September 2014
Quantification of the disorder in network-modified silicate glasses journal July 1992
Charge-transfer crystallites as molecular electrical dopants journal October 2015
Double doping of conjugated polymers with monomer molecular dopants journal January 2019
Towards understanding the doping mechanism of organic semiconductors by Lewis acids journal September 2019
Insight into the structures and dynamics of organic semiconductors through solid-state NMR spectroscopy journal September 2020
Electrical doping in halide perovskites journal March 2021
Efficient molecular doping of polymeric semiconductors driven by anion exchange journal August 2019
Ordered arrangement of F4TCNQ anions in three-dimensionally oriented P3HT thin films journal November 2020
Supramolecular cocrystals built through redox-triggered ion intercalation in π-conjugated polymers journal April 2021
Optical-quality controllable wet-chemical doping of graphene through a uniform, transparent and low-roughness F4-TCNQ/MEK layer journal January 2016
Molecular doping in organic semiconductors: fully solution-processed, vacuum-free doping with metal–organic complexes in an orthogonal solvent journal January 2017
Polymorphism controls the degree of charge transfer in a molecularly doped semiconducting polymer journal January 2018
Disorder-driven doping activation in organic semiconductors journal January 2020
The role of bulk and interfacial morphology in charge generation, recombination, and extraction in non-fullerene acceptor organic solar cells journal January 2020
Impact of p-type doping on charge transport in blade-coated small-molecule:polymer blend transistors journal January 2020
Electron spin as fingerprint for charge generation and transport in doped organic semiconductors journal January 2021
Spin–spin interactions and spin delocalisation in a doped organic semiconductor probed by EPR spectroscopy journal January 2021
Understanding how Lewis acids dope organic semiconductors: a “complex” story journal January 2021
Oxidation of [M(η-C5H5)2], M = Cr, Fe or Co, by the new Brønsted acid H2O·B(C6F5)3 yielding the salts [M(η-C5H5)2]+A−, where A− = [(C6F5)3B(μ-OH)B(C6F5)3]− or [(C6F5)3BOH  · · ·  H2OB(C6F5)3]− † journal January 1999
Synthesis of electrically conducting organic polymers: halogen derivatives of polyacetylene, (CH) x journal January 1977
The effect of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane charge transfer dopants on the conformation and aggregation of poly(3-hexylthiophene) journal January 2013
Solid state 13C NMR in conducting polymers journal January 1985
Lithium doping of semiconducting organic charge transport materials journal May 2001
NMR evidence for the metallic nature of highly conducting polyaniline journal January 1995
Electrical Properties of Phthalocyanine-Halogen Complexes journal December 1979
Structure–Function Relationship of Organic Semiconductors: Detailed Insights From Time-Resolved EPR Spectroscopy journal February 2019
The Applications of Solid-State NMR to Conducting Polymers. The Special Case on Polyaniline journal January 2020

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