Electrodes for Top-Illuminated Organic Photovoltaic Devices: An investigation into electrode design and interfacial energetics

Organic Photovoltaics (OPV), based on semiconducting small molecules and polymers, are a disruptive technology that offer varied advantages to traditional inorganic photovoltaics. OPV structures are typically illuminated through the substrate, placing constraints on the materials available, and often rely on the prohibitively expensive indium-tin-oxide (ITO) as a transparent substrate electrode. To remove the reliance on transparent substrates and ITO, a top-illuminated orientation can be used whereby the transparent substrate electrode is replaced with an opaque highly reflective electrode and the window electrode is moved to the top of the device. This talk explores the development of a novel substrate electrode for top-illuminated OPVs based on an Al|Cu bilayer capped with a sub-nm Al film. The unique properties of this electrode are used to elucidate a design rule for top-illuminated bulk-heterojunction OPVs which is underpinned by studies of the interfacial energetics. Additionally, a solution processable organo-molybdenum oxide bronze is shown which combines the function of a wide band gap hole-transport layer with that of a metal seed layer, enabling the fabrication of highly transparent and low sheet resistance window electrodes.
Dr Martin Tyler studied for a Masters in Chemistry at the University of Warwick from 2008-2012 during which time his interest in organic photovoltaics was first founded through a masters project in the group of Prof. Ross Hatton. After a successful and enjoyable year he decided to continue his research in the group as a PhD student where he worked from 2012-2016 on a project funded by the EPSRC. This focused on the development and investigation of electrode structures in top-illuminated OPVs. He continued this work as a PDRA implementing these technologies into perovskite photovoltaics before moving on to his current position working for the chemical coatings company AkzoNobel in early 2017.