Synthesis and Charge Transport Properties of Conjugated Polymers Incorporating Difluorothiophene as a Building Block

Synthesis, characterization and crystal structures of novel fluorinated di(thiazolyl)benzene derivatives

A series of 11 novel fluorinated and non-fluorinated di(thiazolyl)benzenes have been synthesized via microwave assisted Stille coupling and characterized using X-ray crystallography.

The integrated adjustment of chlorine substitution and two-dimensional side chain of low band gap polymers in organic solar cells

The chlorination and side-chain extension of benzothiadiazole derivatives can finely manipulate the open-circuit voltage in their solar cells.

Interconnecting semiconducting molecules with non-conjugated soft linkers: a way to improve film formation quality without sacrifice in charge mobility

For small molecular semiconductors, interconnecting their molecules with non-conjugated soft linkers has been demonstrated to be a good way for improving their film formation quality while keeping their mobility intact for OFETs.

Isoindigo-Based Polymers with Small Effective Masses for High-Mobility Ambipolar Field-Effect Transistors

So far, most of the reported high-mobility conjugated polymers are p-type semiconductors. By contrast, the advances in high-mobility ambipolar polymers fall greatly behind those of p-type counterparts. Instead of unipolar p-type and n-type materials, ambipolar polymers, especially balanced ambipolar polymers, are potentially serviceable for easy-fabrication and low-cost complementary metal-oxide-semiconductor circuits. Therefore, it is a critical issue to develop high-mobility ambipolar polymers. Here, three isoindigo-based polymers, PIID-2FBT, P1FIID-2FBT, and P2FIID-2FBT are developed for high-performance ambipolar organic field-effect transistors. After the incorporation of fluorine atoms, the polymers exhibit enhanced coplanarity, lower energy levels, higher crystallinity, and thus increased µ_e . P2FIID-2FBT exhibits n-type dominant performance with a µ_e of 9.70 cm² V^-1 s^-1 . Moreover, P1FIID-2FBT exhibits a highly balanced µ_h and µ_e of 6.41 and 6.76 cm² V^-1 s^-1 , respectively, which are among the highest values for balanced ambipolar polymers. Moreover, a concept "effective mass" is introduced to further study the reasons for the high performance of the polymers. All the polymers have small effective masses, indicating good intramolecular charge transport. The results demonstrate that high-mobility ambipolar semiconductors can be obtained by designing polymers with fine-tuned energy levels, small effective masses, and high crystallinity.

Bis-Diketopyrrolopyrrole Moiety as a Promising Building Block to Enable Balanced Ambipolar Polymers for Flexible Transistors

A bis-diketopyrrolopyrrole (DPP dimer, 2DPP) core is synthesized with much stronger electron deficiency than DPP by homocoupling of DPP. 2DPP-based polymers, P2DPP-BT, P2DPP-TT, P2DPP-TVT, and P2DPP-BDT, are obtained. Top-gated organic field-effect transistors on plastic substrate are fabricated. Compared with their mono-DPP-based polymers, remarkable improvement of electron mobilities of P2DPPs is achieved. Meanwhile, their p-channel performance becomes higher.

Diketopyrrolopyrrole Polymers with Thienyl and Thiazolyl Linkers for Application in Field-Effect Transistors and Polymer Solar Cells

Conjugated polymers consisting of diketopyrrolopyrrole (DPP) units have been successfully applied in field-effect transistors (FETs) and polymer solar cells (PSCs), while most of the DPP polymers were designed as symmetric structures containing identical aromatic linkers. In this manuscript, we design a new asymmetric DPP polymer with varied aromatic linkers in the backbone for application in FETs and PSCs. The designation provides the chance to finely adjust the energy levels of conjugated polymers so as to influence the device performance. The asymmetric polymer exhibits highly crystalline properties, high hole mobilities of 3.05 cm² V^-1 s^-1 in FETs, and a high efficiency of 5.9% in PSCs with spectra response from 300 to 850 nm. Morphology investigation demonstrates that the asymmetric polymer has a large crystal domain in blended thin films, indicating that the solar cell performance can be further enhanced by optimizing the microphase separation. The study reveals that the asymmetric design via adjusting the aromatic linkers in DPP polymers is a useful route toward flexible electronic devices.

High-Mobility Ambipolar Organic Thin-Film Transistor Processed From a Nonchlorinated Solvent

Polymer semiconductor PDPPF-DFT, which combines furan-substituted diketopyrrolopyrrole (DPP) and a 3,4-difluorothiophene base, has been designed and synthesized. PDPPF-DFT polymer semiconductor thin film processed from nonchlorinated hexane is used as an active layer in thin-film transistors. As a result, balanced hole and electron mobilities of 0.26 and 0.12 cm(2)/(V s) are achieved for PDPPF-DFT. This is the first report of using nonchlorinated hexane solvent for fabricating high-performance ambipolar thin-film transistor devices.

N. A, B. H. Rational design of benzodithiophene based conjugated polymers for better solar cell performance

We present a concise review of conjugated polymers based on benzodithiophenes (BDTs) for high-performance polymer solar cells (PSCs).