Organic Semiconductors Based on [1]Benzothieno[3,2-b][1]benzothiophene Substructure

Abstract

The design, synthesis, and characterization of organic semiconductors applicable to organic electronic devices, such as organic field-effect transistors (OFETs) and organic photovoltaics (OPVs), had been one of the most important topics in materials chemistry in the past decade. Among the vast number of materials developed, much expectation had been placed on thienoacenes, which are rigid and planar structures formed by fusing thiophenes and other aromatic rings, as a promising candidate for organic semiconductors for high-performance OFETs. However, the thienoacenes examined as an active material in OFETs in the 1990s afforded OFETs with only moderate hole mobilities (approximately 0.1 cm(2) V(-1) s(-1)). We speculated that this was due to the sulfur atoms in the thienoacenes, which hardly contributed to the intermolecular orbital overlap in the solid state. On the other hand, we have focused on other types of thienoacenes, such as [1]benzothieno[3,2-b][1]benzothiophene (BTBT), which seem to have appropriate HOMO spatial distribution for effective intermolecular orbital overlap. In fact, BTBT derivatives and their related materials, including dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT), have turned out to be superior organic semiconductors, affording OFETs with very high mobilities. To illustrate some examples, we have developed 2,7-diphenyl BTBT (DPh-BTBT) that yields vapor-deposited OFETs having mobilities of up to 2.0 cm(2) V(-1) s(-1) under ambient conditions, highly soluble dialkyl-BTBTs (Cn-BTBTs) that afford solution-processed OFETs with mobilities higher than 1.0 cm(2) V(-1) s(-1), and DNTT and its derivatives that yield OFETs with even higher mobilities (>3.0 cm(2) V(-1) s(-1)) and stability under ambient conditions. Such high performances are rationalized by their solid-state electronic structures that are calculated based on their packing structures: the large intermolecular orbital overlap and the isotropic two-dimensional electronic structure are the key regardless of the molecular size and substituents on the BTBT and its related thienoacene cores. Along with the discovery of such attracting performances, versatile and practical methods for the synthesis of BTBT and its derivatives, and the π-extended derivatives including DNTT, dianthra[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DATT), and the thienoacenes with two thieno[3,2-b]thiophene moieties, have been developed. In addition, the materials have been recently utilized in sophisticated devices and circuits, including all-printed transistor arrays, flexible circuits on ultrathin plastic substrates, and biomedical applications, underscoring their promise as practical semiconductors for electronic device applications. These exciting results of the present BTBT-based materials are expected to open doors to new horizons of organic semiconductors in terms of practical application and the design and synthesis of far more superior materials.

High‐Frequency, Conformable Organic Amplifiers

“…[ 38 ] This reduction of work function created a good interface for hole injection to the highest occupied molecular orbital level of dinaphtho [2,3-b:29,39-f ] thieno [3,2-b]thiophene (DNTT), −5.4 eV. [ 39 ] Substrates were spincoated with negative photoresist (ZPN-1150, ZEON Corporation) and fi ne patterning of source and drain was done by LED maskless digital exposure system (PMT Corporation). After exposing the designated areas, 30 nm of gold was thermally evaporated and the "lift-off" technique was applied to obtain the pattern of source and drain.…”

Enhanced performance of field-effect transistors based on C60 single crystals with conjugated polyelectrolyte

“…On the one hand, the conductive channel of the charge carriers forms at the interface between the semiconductor and the dielectric layer [7]. Accordingly, the device improvement is achieved by chemically modifying the molecular structures of the semiconductors [8][9][10][11][12][13][14][15] and the gate dielectrics [16][17][18][19][20][21], adjusting their *Corresponding authors (email: msfhuang@scut.edu.cn; hanying_li@zju.edu.cn) molecular aggregation structures [21][22][23][24][25][26][27][28], and eliminating the charge traps near the channel [29][30][31]. On the other hand, considering the configuration of FETs, charge carriers need to be injected through the electrodes before they reach the conductive channel and thus efficient carriers injection is of great importance to high-performance FETs.…”

Applications of nanoimprint lithography/hot embossing: a review

“…The ink materials to be printed range from DNA molecules, living cells to metallic films [17]. This technique has led to flexible printing for electronics in roll-to-roll format [18][19][20][21][22]. Similar to contact printing, a reversal nanoimprint [8] for resist transferring from templates to substrates was reported, providing an alternative to nanoimprint for parallel patterning with nanometer scale.…”