Anomalous Charge Transport in Conjugated Polymers Reveals Underlying Mechanisms of Trapping and Percolation.

While transport in conjugated polymers has many similarities to that in crystalline inorganic materials, several key differences reveal the unique relationship between the morphology of polymer films and the charge mobility. We develop a model that directly incorporates the molecular properties of the polymer film and correctly predicts these unique transport features. At low degree of polymerization, the increase of the mobility with the polymer chain length reveals trapping at chain ends, and saturation of the mobility at high degree of polymerization results from conformational traps within the chains.

Percolation, Tie-Molecules, and the Microstructural Determinants of Charge Transport in Semicrystalline Conjugated Polymers.

Semiconducting polymers play an important role in a wide range of optical and electronic material applications. It is widely accepted that the polymer ordering impacts charge transport in such devices. However, the connection between molecular ordering and device performance is difficult to predict due to the current need for a mathematical theory of the physics that dictate charge transport in semiconducting polymers.

Very low band gap thiadiazoloquinoxaline donor-acceptor polymers as multi-tool conjugated polymers.

Here we report on the synthesis of two novel very low band gap (VLG) donor-acceptor polymers (Eg ≤ 1 eV) and an oligomer based on the thiadiazoloquinoxaline acceptor. Both polymers demonstrate decent ambipolar mobilities, with P1 showing the best performance of ∼10(-2) cm(2) V(-1) s(-1) for p- and n-type operation. These polymers are among the lowest band gap polymers (≲0.

Photocurrent enhancement from diketopyrrolopyrrole polymer solar cells through alkyl-chain branching point manipulation.

Systematically moving the alkyl-chain branching position away from the polymer backbone afforded two new thieno[3,2-b]thiophene-diketopyrrolopyrrole (DPPTT-T) polymers. When used as donor materials in polymer:fullerene solar cells, efficiencies exceeding 7% were achieved without the use of processing additives. The effect of the position of the alkyl-chain branching point on the thin-film morphology was investigated using X-ray scattering techniques and the effects on the photovoltaic and charge-transport properties were also studied.