N-Fused BDOPV: a tetralactam derivative as a building block for polymer field-effect transistors

3-Methoxythiophene-Based Indophenine Reaction Generating an Isomeric Dynamic Equilibrium System

A 3-methoxythiophene-based indophenine reaction with N-(2-hexyldecyl)isatin in the presence of concentrated sulfuric acid produces an indophenine cis-trans isomeric dynamic equilibrium system, which is dominated by the (Z,E,Z) configuration with a trace of the (Z,Z,Z) configuration.

Recent structural evolution of lactam- and imide-functionalized polymers applied in organic field-effect transistors and organic solar cells

Organic semiconductor materials, especially donor-acceptor (D-A) polymers, have been increasingly applied in organic optoelectronic devices, such as organic field-effect transistors (OFETs) and organic solar cells (OSCs). Plenty of high-performance OFETs and OSCs have been achieved based on varieties of structurally modified D-A polymers. As the basic building block of D-A polymers, acceptor moieties have drawn much attention. Among the numerous types, lactam- and imide-functionalized electron-deficient building blocks have been widely investigated. In this review, the structural evolution of lactam- or imide-containing acceptors (for instance, diketopyrrolopyrrole, isoindigo, naphthalene diimide, and perylene diimide) is covered and their representative polymers applied in OFETs and OSCs are also discussed, with a focus on the effect of varied structurally modified acceptor moieties on the physicochemical and photoelectrical properties of polymers. Additionally, this review discusses the current issues that need to be settled down and the further development of new types of acceptors. It is hoped that this review could help design new electron-deficient building blocks, find a more valid method to modify already reported acceptor units, and achieve high-performance semiconductor materials eventually.

Recent Advances in Isoindigo-Inspired Organic Semiconductors

Over the past decade, isoindigo has become a widely used electron-deficient subunit in donor-acceptor organic semiconductors, and these isoindigo-based materials have been widely used in both organic photovoltaic (OPV) devices and organic field effect transistors (OFETs). Shortly after the development of isoindigo-based semiconductors, researchers began to modify the isoindigo structure in order to change the optoelectronic properties of the resulting materials. This led to the development of many new isoindigo-inspired compounds; since 2012, the Kelly Research Group has synthesized a number of these isoindigo analogues and produced a variety of new donor-acceptor semiconductors. In this Personal Account, recent progress in the field is reviewed. We describe how the field has evolved from relatively simple donor-acceptor small molecules to structurally complex, highly planarized polymer systems. The relevance of these materials in OPV and OFET applications is highlighted, with particular emphasis on structure-property relationships.

Centrosymmetric Thiophenemethyleneoxindole-Based Donor-Acceptor Copolymers for Organic Field-Effect Transistors

Two novel, donor-acceptor-type π-conjugated polymers (P1 and P2) with 3'-(thieno[3,2-b]thiophene-2,5-diylbis(methan-1-yl-1-ylidene))bis-(indolin-2-one) (ITTI) as the acceptor and thiophene/bithiophene as the donor are designed and synthesized by palladium-catalyzed Stille coupling. The optical and electrochemical properties of these polymers are characterized and further implemented into organic field-effect transistors (OFET). Both polymers exhibit excellent thermal stability, broad UV-vis absorption, and high highest occupied molecular orbital energy levels. Thermal annealing induces a well-ordered structure, a highly planar π-system (oxygen-sulfur interaction), and a bathochromic shift in the polymers; furthermore, significant enhancement of the long wavelength intensity is also observed. Both polymers exhibit p-type charge transport behavior, with hole mobilities up to 0.51 cm² V^-1 s^-1 for P1 and 0.65 cm² V^-1 s^-1 for P2. This work demonstrates that ITTI can be a promising building block for the construction of donor-acceptor polymers with high-performance OFETs.

π-Conjugation expanded isoindigo derivatives and the donor-acceptor conjugated polymers: synthesis and characterization

Two π-conjugation expanded isoindigo derivatives (DIID-PhCO and TIID-PhCO) composed of up to 18 rings and two donor-acceptor conjugated polymers based on DIID-PhCO were synthesized. Both polymers are ambipolar semiconductors with balanced hole and electron mobilities up to 0.10 and 0.14 cm² V^-1 s^-1, respectively, under ambient conditions.

A new approach to thiazoloisoindigo and derivatives using a lithium tetramethylpiperidine promoted cyclization to thiazoloisatin

Thiazoloisoindigo and its derivatives were synthesized for the first time from thiazoloisatin, which was obtained via a novel cyclization strategy.

π-Extended Isoindigo-Based Derivative: A Promising Electron-Deficient Building Block for Polymer Semiconductors

The exploration of novel electron-deficient building blocks is a key task for developing high-performance polymer semiconductors in organic thin-film transistors. In view of the situation of the lack of strong electron-deficient building blocks, we designed two novel π-extended isoindigo-based electron-deficient building blocks, IVI and F₄IVI. Owing to the strong electron-deficient nature and the extended π-conjugated system of the two acceptor units, their copolymers, PIVI2T and PF₄IVI2T, containing 2,2'-bithiophene donor units, are endowed with deep-lying highest occupied molecular orbital (HOMO)/lowest unoccupied molecular orbital (LUMO) energy levels and strong intermolecular interactions. In comparison to PIVI2T, the fluorinated PF₄IVI2T exhibits stronger intra- and intermolecular interactions, lower HOMO/LUMO energy levels up to -5.74/-4.17 eV, and more ordered molecular packing with a smaller π-π stacking distance of up to 3.53 Å, resulting in an excellent ambipolar transporting behavior and a promising application in logic circuits for PF₄IVI2T in ambient with hole and electron mobilities of up to 1.03 and 1.82 cm² V^-1 s^-1, respectively. The results reveal that F₄IVI is a promising and strong electron-deficient building unit to construct high-performance semiconducting polymers, which provides an insight into the structure-property relationships for the exploration and molecular engineering of excellent electron-deficient building blocks in the field of organic electronics.

Facile green synthesis of isoindigo-based conjugated polymers using aldol polycondensation

A green and efficient synthetic protocol suitable for the preparation of isoindigo-based polymer was developed using aldol polymerization.

Photovoltaic properties of 3,3′-(ethane-1,2-diylidene)-bis(indolin-2-one) based conjugated polymers

3,3′-(Ethane-1,2-diylidene)-bis(indolin-2-one) (EBI) is a π-conjugated structure in which two oxindoles are connected by a 1,3-butadiene. Two new polymers based on EBI have been synthesized and their photovoltaic properties have been studied.

Lactone-fused electron-deficient building blocks for n-type polymer field-effect transistors: synthesis, properties, and impact of alkyl substitution positions

Dilactone-based Pechmann dyes were incorporated into conjugated polymers for n-type field-effect transistors, providing a new design concept of electron-deficient building blocks for polymer semiconductors.