Chlorinated Conjugated Polymer Based on Chlorine‐ and Cyano‐substituted (E)‐1,2‐Di(thiophen‐2‐yl)ethane for Ambipolar and n‐Type Organic Thin‐film Transistors

Abstract

Comprehensive SummaryChlorinated conjugated polymers are rarely reported in ambipolar and n‐type organic thin‐film transistors (OTFTs), mainly due to the lack of chlorinated strong electron‐deficient building blocks. Herein, we report three new chlorine (Cl)‐ and cyano (CN)‐ substituted (E)‐1,2‐di(thiophen‐2‐yl)ethane building blocks and their copolymers P2Cl1CNTVT‐DPP, P4Cl1CNTVT‐DPP and P2Cl2CNTVT‐DPP. P2Cl1CNTVT‐DPP and P2Cl2CNTVT‐DPP had nearly planar backbone geometries, mixture of edge‐on and face‐on orientation and deeper energy levels, while P4Cl1CNTVT‐DPP had a twist backbone geometry, face‐on orientation and shallower energy levels. As a result, P2Cl1CNTVT‐DPP exhibited ambipolar characteristic with hole mobility (μh) of 0.70 cm2·V–1·s–1 and electron mobility (μe) of 0.84 cm2·V–1·s–1 and P2Cl2CNTVT‐DPP exhibited n‐type characteristic with μe of 0.64 cm2·V–1·s–1, while P4Cl1CNTVT‐DPP exhibited the lowest μe of 0.36 cm2·V–1·s–1. The devices based on P2Cl2CNTVT‐DPP exhibited good stability after being stored for 10 d in air. The results demonstrate that by rational molecular design, chlorinated polymers with low cost can be applied to high‐performance ambipolar and n‐type OTFTs.

Fluorinated Conjugated Polymers Enabled Enhanced Detectivity in Organic Near-Infrared Photodetectors

“…Both PFBDB-T and PFBDB-T-2F showed greater redshifted maximum absorption than that of PBDB-T films, which suggests that F substitution on the thiophene unit in the conjugated backbone enhanced the ICT effect of the CPs. As shown in Figure c, PFBDB-T and PFBDB-T-2F exhibited an increased 0–0/0–1 intensity ratio compared to that of PBDB-T, signifying strongly aggregation behavior . In addition, the maximum absorption cutoffs were found to be 684, 700, and 687 nm for PBDB-T, PFBDB-T, and PFBDB-T-2F, respectively.…”

“…45 The intensity ratio of 0−0 to 0−1 can reveal the degree of intermolecular aggregation of the polymers. The intensities of the 0−0 peaks were higher than those of the 0−1 peaks for PBDB-T, PFBDB-T, and PFBDB-T-2F, indicating 46 In addition, the maximum absorption cutoffs were found to be 684, 700, and 687 nm for PBDB-T, PFBDB-T, and PFBDB-T-2F, respectively. The highest cutoffs indicated that PFBDB-T with two F substitutions exhibited the strongest ICT effect among the three polymers.…”

Structure‐Property Relationship of Conjugated Polymers Utilizing Isomerized Fused Benzothiadiazole‐Based Building Blocks†

“…[ 13‐15 ] Many donor and acceptor building blocks have been developed to construct D‐A type conjugate polymers. [ 16‐20 ] Amongst these building blocks, benzothiadiazole (BTz) is widely used in the construction of high‐performance D‐A type conjugated polymers due to its merits of rigid planar structure, electron deficiency and structural modifiability. [ 21‐22 ] For example, conjugated polymers obtained by copolymerization of benzothiadiazole with indacenodithiophene (IDT), cyclopentadithiophene (CPDT), diketopyrrolopyrrole (DPP) have achieved high‐performance in OPVs and OFETs devices.…”

Regulation of microstructure and charge transport properties of cyclopentadiene-based conjugated polymers via side-chain engineering

“…1–10 The skeleton structures of CPs with high carrier mobility in organic field-effect transistors (OFET) reported in the literature are generally composed of derivatized aromatic units featuring structural diversity, good chemical stability, and so on. 2,11–24 Despite these advantages, their inherent aromatic resonance energy can confine π-electrons to individual aromatic rings to a certain extent, and hence potentially suppress carrier transport through the whole conjugated backbone. 25…”