Organic Semiconductor/Polymer Blend Films for Organic Field‐Effect Transistors

Abstract

The development of low-cost printed organic electronics entails the processing of the active organic semiconductors (OSCs) by solution-based techniques. However, the preparation of large area uniform and reproducible films based on OSCs inks can be very challenging due to the low viscosity of their solutions that give dewetting problems, the low stability of OSC polymer solutions or the difficulty in achieving appropriate crystal order. To circumvent this, a promising route is the use of blends of OSCs and insulating binding polymers. This approach typically gives rise to films with an enhanced crystallinity and organic field-effect transistors (OFETs) with significantly improved device performance. In this review paper, we overview the recent progress realized in the fabrication of OFETs based on OSC/binding polymer inks highlighting the main morphological and structural features that are playing a major role in determining the final electrical properties and some future perspectives.Undoubtedly, the use of this type of blends results in more reliable and reproducible devices that can be fabricated on large areas and at low cost and, thus, this methodology brings great expectations for the implementation of OSCs in real applications.

Impact of p-type doping on charge transport in blade-coated small-molecule:polymer blend transistors

“…27 In recent years, molecular doping of OSCs has emerged as promising method to enhance the performance of solutionprocessed OTFTs. 18,[35][36][37][38][39][40][41][42][43][44][45][46][47][48] In this regard, we have recently developed p-doped OTFTs with hole mobility of 13 cm 2 V À1 s À1 based on spin-coated blend semiconducting channels based on the small-molecule 2,7-dioctyl [1]benzothieno [3,2-b] [1]benzothiophene (C 8 -BTBT), and the polymer poly(indacenodithiophene-cobenzothiadiazole) (C 16 IDT-BT). 16 Key to our success has been the ink-formulation engineering (solvents, material ratios, etc.…”

Selection of the two enantiotropic polymorphs of diF-TES-ADT in solution sheared thin film transistors

“…10 One of the most recently explored technique used to deposit soluble OSCs for OFET fabrication is solution shearing, which has been explored employing bare OSCs and OSCs blended with binding polymers. [11][12][13][14][15][16] This family of techniques has been proved to result in homogenous and highly crystalline thin films exhibiting an enhanced electrical performance.…”

Recent Advances in the Bias Stress Stability of Organic Transistors

“…On the other hand, water acts as a deep trap on both types of OFETs under a constant bias stress, and it not only polarizes the gate dielectric but also decreases the threshold voltage. The incorporation of an insulating polymer into an OSC layer could result in unfavorable phase separation and/or polarity in the polymer's chemical structure . Careful selection of the blend material must be carried out to avoid side effects such as charge trapping at the polar segments of the insulating polymer and disruption of the OSC crystal formation process.…”