Synthesis of Small Band Gap Poly[Bis-EDOT-Isoindigo] via Direct Arylation and Oxidative Electropolymerization, and Its Optoelectronic Properties

Abstract

We have demonstrated a chloride-promoted direct arylation of 6,6′-dibromo-N,N′-(2-ethylhexyl)isoindigo, ID, with 4.0 equivalent of 3,4-ethylenedioxythiophene, EDOT, giving a small band gap donor-acceptor oligomer, 6,6′-bisEDOT-N,N′-(2-ethylhexyl)isoindigo, BEDOTID in 97% yield. The polymerization of BEDOTID was performed by following two approaches; (1) electro-oxidative (homo-coupling) reaction in dichloromethane and (2) Pd-catalyzed oxidative (homo-coupling) reaction in chloroform. These approaches afforded insoluble poly[bis-EDOT-isoindigo], PBDOTID. Characterization of PBEDOTID was performed with the film prepared by electro-oxidative polymerization, which showed low optical and electrochemical band gap properties (1.33 and 1.28 eV, respectively) based on the electron-donating EDOT and electron-accepting isoindigo units. The measurement of the current density on scan rate justified that the obtained PBEDOTID film was uniform.

Evaluating Donor Effects in Isoindigo-Based Small Molecular Fluorophores

“…Synthesis of the isoindigo derivatives were performed using Stille coupling conditions for the II-THIO , II-FURAN , and II-MePyr derivatives, while a C–H activation technique afforded the II-EDOT , as shown in Schemes and . The synthetic details for the II-THIO and II-EDOT derivatives were obtained and revised from the literature, while the II-FURAN and II-MePyr derivatives were synthesized using standard Stille conditions. The intermediates ( II-THIO , II-FURAN , and II-MePyr ) obtained via Stille coupling were attained in moderate to good yields; 70, 98, and 75%, respectively.…”

“…Flash column chromatography was performed using a Purasil SiO 2 -60, 230–400 mesh from Whatman. The synthesis was derived and modified from previously published works. − In brief, the II-Furan, II-MePyr, and II-Thio derivatives were synthesized using standard Stille conditions. , The II-EDOT derivative was synthesized using a C–H activation technique . The II-FURAN-TPA , II-MePyr-TPA , II-THIO-TPA , and II-EDOT-TPA derivatives were synthesized using standard Suzuki conditions .…”

“…29,30 The II-EDOT derivative was synthesized using a C−H activation technique. 31 The II-FURAN-TPA, II-MePyr-TPA, II-THIO-TPA, and II-EDOT-TPA derivatives were synthesized using standard Suzuki conditions. 32 Additional details regarding synthesis and characterization of II-X-TPA derivatives can be found in the Supporting Information.…”

Electrochemical Copolymerization of Isoindigo‐Based Donor‐Acceptor Polymers with Intrinsically Enhanced Conductivity and Near‐Infrared‐II Activity

“…The isoindigo acceptor has been shown to be synthetically manipulated with ease, allowing for the control and tunability of its unique properties. Formation of D−A CPs using isoindigo as the acceptor has been mainly relegated to thermal chemical synthesis with very few reports utilizing electrochemical polymerization techniques . Research that does utilize electrochemical means of polymerization primarily focuses on the formation of homopolymers of the respective isoindigo monomers.…”

Organic Photovoltaics Based on Poly(3,4-phenylenedioxy-2,5-thienylenevinylene)s

“…[1][2][3][4][5] Owing to their outstanding characteristics, many PEDOT derivatives have been developed and applied to printed electronic devices such as organic photovoltaic cells (OPVs) and organic field-effect transistors. [6][7][8][9] For example, Roquet and co-workers have designed 3,4-phenylenedioxythiophene (PhDOT), which has a planar structure, by replacing the ethylene bridge of ethylenedioxythiophene with a phenylene unit and synthesized poly(PhDOT) (PPhDOT). 10,11 PPhDOT is expected to be an alternative to PEDOT because it exhibits a smaller E g and better conductivity than PEDOT.…”