Enhancing Field‐Effect Mobility of Conjugated Polymers Through Rational Design of Branched Side Chains

Abstract

The design of polymer semiconductors possessing effective π–π intermolecular interactions coupled with good solution processability remains a challenge. Structure‐property relationships associated with side chain structure, π–π intermolecular interactions, polymer solubility, and charge carrier transport are reported for a donor–acceptor(1)‐donor–acceptor(2) polymer: 5‐Decylheptadecyl (5‐DH), 2‐tetradecyl (2‐DT), and linear n‐octadecyl (OD) chains are substituted onto a polymer backbone consisting of terthiophene units (T) between two different electron acceptors, benzothiadiazole (B), and diketopyrrolopyrrole (D), pTBTD, to afford pTBTD‐5DH, pTBTD‐2DT, and pTBTD‐OD, respectively. In the 5‐DH side chain, the branching position is remote from the polymer backbone, whereas it is proximal in 2‐DT. This study demonstrates that incorporation of branched side chains where the branching position is remote from the polymer backbone merges the advantages of improved solubility from branched units with effective π–π intermolecular interactions normally associated with linear chains on conjugated polymers. pTBTD‐5DH exhibits superior qualities with respect to the degree of polymerization, solution processability, π–π interchain stacking, and charge carrier transport relative to the other analogs. pTBTD‐5DH exhibits a field‐effect hole mobility of up to 2.95 cm2 V–1 s–1, a factor of 3–7 times that achieved with pBDT6‐DT and pBDT6‐OD.

ε‐Branched Flexible Side Chain Substituted Diketopyrrolopyrrole‐Containing Polymers Designed for High Hole and Electron Mobilities

“…GIXD patterns were recorded with a 2D CCD detector (Rayonix SX165) and X-ray irradiation time was ranged from 30 s to 60 s, depending on the saturation level of the detector. Diffraction angles were calibrated using a pre-calibrated sucrose ( 4 (6 mg) as the catalyst was applied, respectively, since the polymerization mixture gelated within 30 min to 1 h under Pd 2 (dba) 3 /P( o -tolyl) 3 . The mixture was heated at 110 °C for 24 h. After cooling to room temperature, it was poured into methanol and the resulting precipitate was fi ltered.…”

“…[ 1 ] Consequently, great efforts in materials design have boosted the FET mobilities achievable from semiconducting polymers up to 2-octyl-1-dodecanol in four steps (iodination, Grignard reaction, hydroboration-oxidation, and re-iodination). [ 4 ] The dibrominated DPP monomer ( 1 ) was synthesized by alkylation of the DPP core with the alkyl iodide, followed by bromination. The synthetic details and characterization data are provided in the Supporting Information (SI).…”

The role of structural and electronic factors in shaping the ambipolar properties of donor–acceptor polymers of thiophene and benzothiadiazole

“…An electron-deficient BT unit has been attached to electron rich molecules such as thiophene derivatives resulting in unique optical and electrochemical properties [23][24][25][26][27]. When BT is incorporated with electron donor units, the extension of the conjugated length appears, due to the occurrence of intarmolecular charge transfer (ICT) in D-A structure [28,29].…”

Hydrogen bond directed assembly of oligothiophene/fullerene superstructures on Au(111)

“…As the solid-state assembly of functional p-conjugated materials is generally controlled by an ensemble of similarly weak intermolecular interactions, securing a designed solid-state organization, and performanceenhancing morphology, is challenging. Hence, molecularlevel approaches and/or material processing conditions which promote predictable organization of p-systems are needed to realize significant advances in device performance [5][6][7][8][9].…”