Vacuum Web processing
Prof. H.E. Assender, Dr. C. Barker
Development of coating techniques and materials using our unique roll-to-roll vacuum web processing capability. The coater can run a 35cm polymer web at speeds of up to 5m/s to allow the deposition of multiple layers from the following sources: i) evaporation, ii) dual magnetron sputter, iii) plasma iv) flash evaporation of organic materials with e-beam cure. Films can be produced for applications such as controlled optical properties and surface finish, high and low energy surfaces, barrier layers, biocompatibilisation or electronic devices.

Vacuum deposition of organic photovoltaic devices
N. Klein, Prof. A.A.R. Watt, Prof. H.E. Assender
Conjugated organic materials have demonstrated attractive properties in terms of light absorption and hole-transport. However, the use of solvents substantially limits the complexity of the devices as the coating solutions interfere with already deposited layers. Vacuum deposition is a solvent-free process, advantageous for its simplicity and ability to evaporate unlimited number of layers with well controlled thickness and composition. This project explores a number of novel organic device architectures, including combining organic layers with nano-scale inorganic inclusions.

Roll-to-roll processing of organic electronics
T. Cosnahan, K. Zhang, Prof. H.E. Assender
Electronics components that can be manufactured using roll-to-roll processing offer the possibility of lower cost devices as well as those that might be mechanically flexible in use. Roll-to-roll (R2R) processing, using a flexible substrate (typically a polymer film) allows for cheap production of many components very rapidly, with low energy requirements. Key areas of exploitation of this technology include flexible displays, but there is also a wealth of lower-cost applications. Tagging and tracking of fast moving consumer goods is an example technology that truly exploit the very low-cost nature of the production and in which the manufacturing is closely linked to the manufacturing routes currently exploited for e.g. packaging technologies.
This project seeks to exploit the existing industrialised technology of vacuum R2R processing, widely used for example in the packaging industry, to develop the manufacture of very low cost organic field-effect transistor (OFET)-based devices and circuits. This manufacturing route, like solvent based systems, is cheap and provides flexible product, and we can exploit high electrical mobility molecular semiconductors. Additional advantages of the solvent-free vacuum processes include: a) likely enhanced web-speed, b) integration with vacuum-based metal deposition for conducting channels, and metal or ceramic deposition for barrier layers and possible interfacial modification, and c) the ability to deposit multiple thin layers to build up device structures without solvent interactions with underlying layers.

Patterned layers for R2R production of organic electronics
T. Cosnahan, Prof. H.E. Assender
The project is investigating a range of possible in-line roll-to-roll patterning techniques for the production of 2-dimensionally patterned layers in vacuum, for example for the low-cost production of flexible electronics.

Roll-to-roll manufacture of organic field effect transistor-based sensors
K. Zhang, Prof. H.E. Assender
Design, manufacture and testing of sensors based on vacuum-evaporated organic charge modulated field effect transistors. A basic pH sensor has already been demonstrated, and this project will extend this to other analytes and understanding of the parameters to maximize sensitivity and selectivity.

Deposition of acrylate layers on polymer substrates by roll-to-roll coating in vacuum
C. Alonso-Herr, Prof. H.E. Assender
An investigation into the deposition of polymer layers by flash evaporation of monomer followed by curing in a high-speed roll-to-roll process. This project will consider the control of the degree and area of cure, and the role of acrylate chemistry and monomer mixtures.

Self-assembly of peptides on surfaces
C. Wang, Prof. H.E. Assender
An investigation of the effect of the underlying substrate on the structure and self-ordering of peptide sequences in thin films. We are examining the formation of gels, fibres & helices with controlled substrate interactions and examining the role of surface charge, and mechanical forces during the deposition of the thin film.

Pattern deposition of polymers by roll-to-roll vacuum deposition
E. Howland, Prof. H.E. Assender
Continuous polymer layers can be deposited by flash evaporation of monomer followed by curing in a high-speed roll-to-roll process. We are investigating routes to selective area curing to produce patterned polymer layers.

Roll-to-roll deposition of thermoelectric materials
X. Tao, Prof. H.E. Assender
The large-area manufacture of thermoelectric devices based on sputter-deposited semiconductor layers is investigated considering the manufacture of devices by roll-to-roll deposition onto polymer substrates.

Ordering in thin film polymers
H. Luo, Prof P.D. Nellist, Prof. H.E. Assender
Thin film polymers have been shown to show particular crystalline morphologies and crystallization temperatures due to diffusion and molecular mobility constraints associated both with the thickness of the film, but also interfacial interactions. We are investigating such near-free surface and near-interfacial ordering using atomic force and electron microscopies.