Comparison of the π-conjugated ring orientations in polyaniline and polypyrrole

Polymer Photoelectrodes for Solar Fuel Production: Progress and Challenges

Converting solar energy to fuels has attracted substantial interest over the past decades because it has the potential to sustainably meet the increasing global energy demand. However, achieving this potential requires significant technological advances. Polymer photoelectrodes are composed of earth-abundant elements, e.g. carbon, nitrogen, oxygen, hydrogen, which promise to be more economically sustainable than their inorganic counterparts. Furthermore, the electronic structure of polymer photoelectrodes can be more easily tuned to fit the solar spectrum than inorganic counterparts, promising a feasible practical application. As a fast-moving area, in particular, over the past ten years, we have witnessed an explosion of reports on polymer materials, including photoelectrodes, cocatalysts, device architectures, and fundamental understanding experimentally and theoretically, all of which have been detailed in this review. Furthermore, the prospects of this field are discussed to highlight the future development of polymer photoelectrodes.

Modelling charge transport in organic semiconductors: from quantum dynamics to soft matter

The charge carrier dynamics in organic semiconductors has been traditionally discussed with the models used in inorganic crystalline and amorphous solids but this analogy has severe limitations because of the more complicated role of nuclear motions in organic materials. In this perspective, we discuss how a new approach to the modelling of charge transport is emerging from the alliance between the conventional quantum chemical methods and the methods more traditionally used in soft-matter modelling. After describing the conventional limit cases of charge transport we discuss the problems arising from the comparison of the theory with the experimental and computational results. Several recent applications of numerical methods based on the propagation of the wavefunction or kinetic Monte Carlo methods on soft semiconducting materials are reviewed.

Photohole Screening Effects in Polythiophenes with Pendant Groups

We compare two mechanisms that dominate the temperature-dependent changes in electronic structure for poly(3-hexylthiophene-2,5 diyl) (P3HT). Structural changes in the relative orientation and configuration of the aromatic ring backbone are observed to occur over a wide range in temperature and affect the local final state screening in photoemission. There are also changes in conductivity and carrier concentration at lower temperatures leading to altered long-range intramolecular screening of photoholes and final state effects that affect excitation spectroscopies including photoemission. For polyethylenedioxythiophene (PEDOT), temperature-dependent changes in the structure and configuration of the polymer backbone are not as significant, although temperature-dependent final state effects are observed.