Energy harvesting using organic electronics

Organic semiconductors (OSCs) have beneficial uses in energy harvesting including thermoelectric and photovoltaic applications. However, the fundamental understanding of why some materials work better than others and chemical engineering present in the literature, such as side chain functionalisation and backbone modification as two typical approaches when trying to improve a material, is sometimes overlooked, and perceived to be universal. This can lead to new materials with undesired characteristics being produced, showing low performance for their application, and eventually being placed in the "dustbin of history". Therefore, the experiments within this thesis aim to show systematic studies on functionalisation's found in the literature including polar side chains for dopant stability and miscibility, polythiophene co-polymers for improved charge transport, highly orientated polymers films for thermoelectrics and cation size dependence on radical anion salts for doping OSCs. Using an array of optical, electrochemical, structural, and electrical measurements, the findings show that methodically using the stated functionalisation approaches on simple OSC materials, such as poly(3-hexylthiohene), can either lead to improved or worse characteristics for their uses. Hopefully, these findings will be considered when new and improved materials are synthesised, and the desired structure-function relationship is considered with care to obtain the right material for the right application.