New materials for organic photovoltaics

This thesis has investigated commercialization of organic solar cells with incorporated low cost, high efficiency donor PDCBT polymer and acceptor ITIC small molecular compound materials to improve the efficiency, lifetime of devices, and critically to keep material large scale production cost as low as possible. The thesis includes a review on device performance from new organic photovoltaic materials fabricated in the literature published to date. Firstly, methodology based on selection of contemporary donor acceptor materials for the upscaled application will be discussed and comparison of these new materials versus benchmark compounds will be introduced. The large scale organic synthesis of traditional active layer materials such as poly(3hexylthiophene) P3HT polymer, [6,6]-phenyl-C61-butyric acid methyl ester (PCBM or C60PCBM), ICxA fullerenes and poly(3,4-ethylenedioxythiophene):poly(styrene) sulfonate (PEDOT:PSS) conducting polymer is undertaken. Then, PDCBT polymer and ITIC small molecule compounds are synthesised on a small scale and improvements and challenges encountered during the preparation is discussed in terms of translation to large scale synthesis. The characterization of standard P3HT:PCBM and PDCBT:ITIC organic solar cell performance, in contrast to the PDCBT:ITIC NP devices manufactured at the University of Newcastle during the course of this PhD will be examined to demonstrate device efficiency improvements over the time of this research project (2016-2022). Furthermore, to further examine and broaden the understanding of the chemistry and physics of large-scale synthesis, flow chemistry, as a method of production for selected materials is examined this work. Although, vigorous recent progress has been made in the development of novel photoactive materials and the COE has already demonstrated the economical production of >100 m2 of printed organic solar at ~1% power conversion efficiency, the challenge of highly efficient, long lifetime and low-cost material application at large scale production still exists. Finally, optimisation of bulk heterojunction blend in OPV devices was examined to address existing issue of cost limitation for high performance new generation materials. This thesis demonstrates how we can identify, synthesise, test, and scale up new active layer materials for use in large scale roll-to-roll printed organic BHJ and nanoparticulate solar cells, to improve the power conversion efficiency while maintaining a low cost of the solar modules.