Fundamentals of Organic and Inorganic Semiconductors and Materials Synthesis and Processing
This module will refresh the basic properties of semiconducting materials, highlighting the key similarities and differences between electronic behaviour in organic and inorganic materials. It will cover the physics of the electronic structure of pi-conjugated materials and their neutral, excited and charged states (excitons, polarons), their optical properties (absorption, emission, gain), photophysical processes, photochemistry, charge and exciton transport. This will include an introduction to the techniques used to model the electrical and optical properties of molecular materials. Aspects of other material properties such as ferroelectricity, thermoelectricity and magnetism will be introduced.
The second half of the module will cover the preparation and deposition of electroactive materials including the organic, inorganic and hybrid components used in plastic electronic devices. Such electroactive materials will include small molecular charge transport materials, sensitising dyes used in solar cells, fluorescent and phosphorescent materials as well as electroactive polymers. The key concepts of conjugation, synthesis (e.g. by Suzuki or Yamamoto coupling, living polymerisations by McCullough route) and relevant characterisation (e.g. by spectroscopy, mass spectrometry, elemental analysis, GPC, cyclic voltametry) will underpin the organic components of the module which should enable students to select molecules for specific (opto)electronic applications and to suggest functionalisation (i.e. fluorination etc.) that will optimise their physical properties. Methods to chemically and physically deposit layers of inorganic and hybrid materials such as transparent oxides, metal sulphides and solution-processable perovskites will also be considered. The key kinetic and thermodynamic concepts underlying the control of morphology, crystallisation, phase behaviour, and processing of single and multi-component systems used in devices will also be covered.
Materials Characterisation and Device Physics and Applications
In conjunction with the Materials and Processing module, this part of the course will introduce materials characterisation techniques relevant to assessing the microstructure and surface/interface properties of relevant electroactive materials including microscopy, X-ray diffraction, rheology and thermal analysis (including degradation). The module will also introduce steady-state and time-resolved spectroscopic techniques suitable for interrogating structural properties, excited states, and charge carriers in electroactive materials. Knowledge of these techniques should provide students with a platform to start tackling the practical problems they will encounter during their projects.
The module will also cover the basic principles of operation and design and molecular and hybrid light emitting devices, solar cells, photodiodes, thin film transistors, polymer lasers, gain media, lighting and displays. Emerging devices classes will also be introduced including spintronic and bioelectronics devices. The module will also introduce device fabrication (including encapsulation) and device engineering for maximum performance and lifetime. Methods to evaluate and assess device performance and bottlenecks will be covered (e.g. solar cell operating efficiency, transistor transfer curves). This understanding will provide students with approaches to diagnose and rectify problems in their device designs.