Title: Understanding how Lewis acids dope organic semiconductors: a “complex” story

Abstract

We report on computational studies of the potential of three borane Lewis acids (LAs) (B(C₆F₅)₃ (BCF), BF₃, and BBr₃) to form stable adducts and/or to generate positive polarons with three different semiconducting p-conjugated polymers (PFPT, PCPDTPT and PCPDTBT). Density functional theory (DFT) and timedependent DFT (TD-DFT) calculations based on range-separated hybrid (RSH) functionals provide insight into changes in the electronic structure and optical properties upon adduct formation between LAs and the two polymers containing pyridine moieties, PFPT and PCPDTPT, unravelling the complex interplay between partial hybridization, charge transfer and changes in the polymer backbone conformation. We then assess the potential of BCF to induce p-doping in PCPDTBT, which does not contain pyridine groups, by computing the energetics of various reaction mechanisms proposed in the literature. We find that reaction of BCF(OH₂) to form protonated PCPDTBT and [BCF(OH)]^-, followed by electron transfer from a pristine to a protonated PCPDTBT chain is highly endergonic, and thus unlikely at low doping concentration. The theoretical and experimental data can, however, be reconciled if one considers the formation of [BCF(OH)BCF]^- or [BCF(OH)(OH₂)BCF]^- counterions rather than [BCF(OH)]^- and invokes subsequent reactions resulting in the elimination of H₂.

Authors:

Marqués, Pablo Simón ^[1]; Londi, Giacomo  ^[2];

• Search DOE PAGES for author "Londi, Giacomo"
• Search DOE PAGES for ORCID "0000-0001-7777-9161"

Yurash, Brett ^[3]; Nguyen, Thuc-Quyen  ^[3];

• Search DOE PAGES for author "Nguyen, Thuc-Quyen"
• Search DOE PAGES for ORCID "0000-0002-8364-7517"

Barlow, Stephen  ^[4];

• Search DOE PAGES for author "Barlow, Stephen"
• Search DOE PAGES for ORCID "0000-0001-9059-9974"

Marder, Seth R. ^[4]; Beljonne, David  ^[2]

• Search DOE PAGES for author "Beljonne, David"
• Search DOE PAGES for ORCID "0000-0001-5082-9990"

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+ Show Author Affiliations

1. Laboratoire MOLTECH-Anjou, UMR CNRS 6200, UNIV Angers, SFR MATRIX, 49045 Angers Cedex
2. Laboratory for Chemistry of Novel Materials, University of Mons, 7000 Mons, Belgium
3. Center for Polymers and Organic Solids, Department of Chemistry & Biochemistry, University of California, Santa Barbara, USA
4. Center for Organic Photonics and Electronics, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, USA

Publication Date:

Wed May 26 00:00:00 EDT 2021

Research Org.:

Univ. of California, Santa Barbara, CA (United States)

Sponsoring Org.:

USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division; Marie Sklodowska-Curie Grant; Fonds de la Recherche Scientifiques de Belgique; Walloon Region; National Science Foundation (NSF)

OSTI Identifier:

1779354

Alternate Identifier(s):

OSTI ID: 1816989

Grant/Contract Number:  

SC0017659; 722651; 2.5020.11; 1117545; DMR-1729737

Resource Type:

Published Article

Journal Name:

Chemical Science

Additional Journal Information:

Journal Name: Chemical Science Journal Volume: 12 Journal Issue: 20; Journal ID: ISSN 2041-6520

Publisher:

Royal Society of Chemistry (RSC)

Country of Publication:

United Kingdom

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY