CPE Winter Symposium

Development of conjugated polymers for organic electronics

Over the past two decades, organic electronics, such as organic field-effect transistors, organic light emitting diodes, organic photovoltaic cells, and organic photodetectors have recently received significant attention for use in flexible low-cost electronics applications.

The molecular design of organic semiconductors is a useful strategy for high performance organic solar cells, organic thin film transistor because tailoring the molecular structures can dramatically tune the properties of the organic semiconductors. In this presentation, I will introduce the characteristics of the conjugated polymers designed and synthesized for various organic electronics applications.

Garry Rumbles

Dynamic range electron transfer: the role of Marcus theory in an OPV system

This presentation will be based on a recent paper (DOI: 10.1039/D1MH01331A) where we use a Marcus formulation to explain how free charges are generated in a sensitized, electron-accepting host system. The important conclusions of the work that will be discussed are the role of the charge-transfer (CT) state, which we claim competes with free carrier (FC) generation, and does not serve as a mediator in the process. The importance of the re-organization energies for both the CT and FC states along with the so-called beta term that describes the distance dependence of the electronic coupling term will be explored in detail. The talk will conclude with our current studies aimed at directly tracking the CT state and the role of competing energy transfer processes.

Barry P Rand

Order, disorder and energy loss in organic photovoltaics

We will discuss our recent work to better understand the role of charge transfer (CT) states in organic solar cell function. For one, we have been exploring organic semiconductor-based thin films that feature crystalline grains of up to 1 mm in extent, termed microcrystalline films. We have found that CT states incorporating these long-range-ordered films can be highly delocalized, contributing to noticeably lower energy losses. In another system, we are studying donor-acceptor pairs that feature very high optical gaps (>3 eV) but relatively small frontier orbital energy offset (<1 eV). Such interfaces present multiple CT states that reveal new insight about photocurrent generation and nonradiative recombination at donor-acceptor interfaces. Finally, we have developed a framework to discriminate between dynamic and static disorder contributions. Both are shown to contribute, and the relative contribution depends on materials choice and temperature.

Jang-Joo Kim

Talk title and abstract TBC

Alex Ganose

Computer-aided insights into materials properties

The temperature dependence of carrier mobility is commonly used to understand the nature of transport in solid-state materials. In this work, I use a combination of high-throughput workflows and machine learning to generate a dataset of 24,000 mobility calculations. Based on this dataset, I demonstrate that the temperature-dependence of mobility is not a reliable indicator of the scattering physics of a material – in contrast to 50 years of conventional thought. This work highlights the potential for data driven approaches to provide insights for materials discovery and optimisation.

Jarvist Frost

Charge carrier mobility

Abstract TBC