On the phase behaviour of organic semiconductors

Abstract

The physical organisation, from the molecular to the macroscale, of functional organic matter such as polymer semiconductors can profoundly affect the properties and features of the resulting architectures and their consequent performance when used as active layers in organic optoelectronic devices, including organic thin-film field-effect transistors, organic light-emitting diodes or organic photovoltaic cells. Here, we present a survey on the principles of structure development from the liquid phase of this interesting and broad class of materials with focus on how to manipulate their phase transformations and solid-state order to tailor and manipulate the final 'morphology' towards technological and practical applications.

Tuning the Optical and Self‐Assembly Properties of Diketopyrrolopyrrole Semicarbazone Derivatives through Hydrogen Bonding

“…Both, the optoelectronic properties and the structural aspects of these systems have to be optimized to reach good performance in the final applications. The structures formed can be controlled by rational design or by applying different processing techniques . Supramolecular chemistry is an alternative to achieve such control, especially when using small molecules.…”

Fast scanning chip calorimetry study of P3HT/PC61BM submicron layers: structure formation and eutectic behaviour

“…Several studies have already indicated that P3HT/PC 61 BM exhibits eutectic phase behaviour, apparent through the melting point depression of the two components when mixed . At the eutectic composition, both components solidify or desolidify simultaneously.…”

“…This yields a fine grain morphology upon cooling which, although not a one‐phase system, will desolidify upon heating at a single temperature and form again a mixed phase of eutectic composition. It is known that P3HT and PC 61 BM are miscible in the amorphous phase, while leading to separate P3HT or PC 61 BM crystals . Different P3HT/PC 61 BM ratios are described in the literature for the eutectic composition, depending on the methodology and the P3HT used .…”

Molecular weight dependence of carrier mobility and recombination rate in neat P3HT films

“…One key factor is the molecular weight of the polymer. Variations in molecular weight can directly affect the solid‐state structure of polymers such as the prototypical poly(3‐hexylthiophene) (P3HT) . At very low molecular weights P3HT forms a one‐phase, paraffinic structure comprised of unconnected, chain‐extended crystallites.…”