Functional films underpin many electronic and opto-electronic devices, including flat panel displays, OLED's, image sensors, thin film photovoltaic solar cells, etc. Of particular importance to these devices are transparent conductive oxide (TCO) films, such as indium tin oxide (ITO) and aluminium-doped zinc oxide (ZAO). The UK market for functional films is expected to rise to 23.4B by 2010. Further substantial gains in productivity would be made, and new markets opened up, if the devices could be deposited directly onto polymeric web in very large throughput reel-to-reel coaters. However, the deposition of TCO films onto webs poses many significant technological challenges. In comparison to glass, polymeric webs are relatively rough, tend to outgas significantly and are thermally sensitive. The latter point particularly poses a problem, because it is generally necessary to perform a post-deposition annealing process (typically at 500 degC) in order to optimise the optical and electrical properties of TCO materials.One potential solution to this problem is to deposit coatings using the newly developed technique of high powered impulse magnetron sputtering (HIPIMS). This process involves the application of very large power pulses to magnetron sputter cathodes for short periods of time. The peak pulse power can be in the megawatt range and the pulse duration is typically of the order of 80-160 micro seconds, at repetition rates in the range of 10s to 100s of Hz. Initial studies of the HIPIMS (also referred to as high power pulsed magnetron sputtering / HPPMS) system have shown that this intense pulse creates a high degree of ionization (up to 70% for titanium) of the sputtered species with this technique (in contrast to conventional magnetron sputtering, where usually less than 1% of the sputtered material is ionized).The degree of ionization of the sputtered species in HIPIMS is comparable to that produced in cathodic arc discharges; however, with HIPIMS macroparticles are not normally produced. Another important consideration is that, due to the very low duty cycles (~1%) and long off times, the total heat load to the substrate can be very significantly (5-10 times) lower than in conventional DC and pulsed DC sputtering. Thus, the potential for HIPIMS is to harness the high degree of ionization to produce films with significantly improved properties, whilst maintaining a suitably low (sub-150 degC) substrate bulk temperature, allowing a diverse range of substrate materials to be coated. The introduction of HIPIMS technology, therefore, has the potential to provide a step-change in the performance of functional films, such as TCO's, deposited onto polymeric webs. This project will offer the first opportunity to study this new, complex deposition process in detail in both a development-scale system at MMU and an industrial pilot scale reel-to-reel coater at Oxford University. An additional key element of the project will be a detailed study of the nature of the discharge. Plasma characteristics such as the spatial and temporal evolution of the concentrations and temperatures of the species and their power loading of the substrate will be determined using an array of time-resolved diagnostic tools and well developed optical imaging techniques. The ability to deposit fully dense TCO coatings with optimised properties onto flexible substrates would be a major breakthrough and would represent a significant advancement in web coating technology.

Functional films underpin many electronic and opto-electronic devices, including flat panel displays, OLED's, image sensors, thin film photovoltaic solar cells, etc. Of particular importance to these devices are transparent conductive oxide (TCO) films, such as indium tin oxide (ITO) and aluminium-doped zinc oxide (ZAO). The UK market for functional films is expected to rise to 23.4B by 2010. Further substantial gains in productivity would be made, and new markets opened up, if the devices could be deposited directly onto polymeric web in very large throughput reel-to-reel coaters. However, the deposition of TCO films onto webs poses many significant technological challenges. In comparison to glass, polymeric webs are relatively rough, tend to outgas significantly and are thermally sensitive. The latter point particularly poses a problem, because it is generally necessary to perform a post-deposition annealing process (typically at 500 degC) in order to optimise the optical and electrical properties of TCO materials.One potential solution to this problem is to deposit coatings using the newly developed technique of high powered impulse magnetron sputtering (HIPIMS). This process involves the application of very large power pulses to magnetron sputter cathodes for short periods of time. The peak pulse power can be in the megawatt range and the pulse duration is typically of the order of 80-160 micro seconds, at repetition rates in the range of 10s to 100s of Hz. Initial studies of the HIPIMS (also referred to as high power pulsed magnetron sputtering / HPPMS) system have shown that this intense pulse creates a high degree of ionization (up to 70% for titanium) of the sputtered species with this technique (in contrast to conventional magnetron sputtering, where usually less than 1% of the sputtered material is ionized).The degree of ionization of the sputtered species in HIPIMS is comparable to that produced in cathodic arc discharges; however, with HIPIMS macroparticles are not normally produced. Another important consideration is that, due to the very low duty cycles (~1%) and long off times, the total heat load to the substrate can be very significantly (5-10 times) lower than in conventional DC and pulsed DC sputtering. Thus, the potential for HIPIMS is to harness the high degree of ionization to produce films with significantly improved properties, whilst maintaining a suitably low (sub-150 degC) substrate bulk temperature, allowing a diverse range of substrate materials to be coated. The introduction of HIPIMS technology, therefore, has the potential to provide a step-change in the performance of functional films, such as TCO's, deposited onto polymeric webs. This project will offer the first opportunity to study this new, complex deposition process in detail in both a development-scale system at MMU and an industrial pilot scale reel-to-reel coater at Oxford University. An additional key element of the project will be a detailed study of the nature of the discharge. Plasma characteristics such as the spatial and temporal evolution of the concentrations and temperatures of the species and their power loading of the substrate will be determined using an array of time-resolved diagnostic tools and well developed optical imaging techniques. The ability to deposit fully dense TCO coatings with optimised properties onto flexible substrates would be a major breakthrough and would represent a significant advancement in web coating technology.

Functional films underpin many electronic and opto-electronic devices, including flat panel displays, OLED's, image sensors, thin film photovoltaic solar cells, etc. Of particular importance to these devices are transparent conductive oxide (TCO) films, such as indium tin oxide (ITO) and aluminium-doped zinc oxide (ZAO). The UK market for functional films is expected to rise to 23.4B by 2010. Further substantial gains in productivity would be made, and new markets opened up, if the devices could be deposited directly onto polymeric web in very large throughput reel-to-reel coaters. However, the deposition of TCO films onto webs poses many significant technological challenges. In comparison to glass, polymeric webs are relatively rough, tend to outgas significantly and are thermally sensitive. The latter point particularly poses a problem, because it is generally necessary to perform a post-deposition annealing process (typically at 500 degC) in order to optimise the optical and electrical properties of TCO materials.One potential solution to this problem is to deposit coatings using the newly developed technique of high powered impulse magnetron sputtering (HIPIMS). This process involves the application of very large power pulses to magnetron sputter cathodes for short periods of time. The peak pulse power can be in the megawatt range and the pulse duration is typically of the order of 80-160 micro seconds, at repetition rates in the range of 10s to 100s of Hz. Initial studies of the HIPIMS (also referred to as high power pulsed magnetron sputtering / HPPMS) system have shown that this intense pulse creates a high degree of ionization (up to 70% for titanium) of the sputtered species with this technique (in contrast to conventional magnetron sputtering, where usually less than 1% of the sputtered material is ionized).The degree of ionization of the sputtered species in HIPIMS is comparable to that produced in cathodic arc discharges; however, with HIPIMS macroparticles are not normally produced. Another important consideration is that, due to the very low duty cycles (~1%) and long off times, the total heat load to the substrate can be very significantly (5-10 times) lower than in conventional DC and pulsed DC sputtering. Thus, the potential for HIPIMS is to harness the high degree of ionization to produce films with significantly improved properties, whilst maintaining a suitably low (sub-150 degC) substrate bulk temperature, allowing a diverse range of substrate materials to be coated. The introduction of HIPIMS technology, therefore, has the potential to provide a step-change in the performance of functional films, such as TCO's, deposited onto polymeric webs. This project will offer the first opportunity to study this new, complex deposition process in detail in both a development-scale system at MMU and an industrial pilot scale reel-to-reel coater at Oxford University. An additional key element of the project will be a detailed study of the nature of the discharge. Plasma characteristics such as the spatial and temporal evolution of the concentrations and temperatures of the species and their power loading of the substrate will be determined using an array of time-resolved diagnostic tools and well developed optical imaging techniques. The ability to deposit fully dense TCO coatings with optimised properties onto flexible substrates would be a major breakthrough and would represent a significant advancement in web coating technology.

The use of colour in every consumer product is ubiquitous. However with increasing concern for the environment, the use of traditional dyes is becoming problematic. This has opened up new opportunities in producing colour by carving out materials at scales smaller than a millionth of a metre, built of components which are benign. In addition, the new possibilities available for structural colours (iridescent, prismatic, multi-hue, or luminescent) are universally attractive in competitive marketplaces such as mobile electronics, fashion, and automotive/airline industries.We have invented a new process for making plastic films which have appealing structural colours, that can be scaled up to industrial production levels. It is based on making periodic arrangements of stacked nano-spheres with a different optical density to their surroundings, called 3D photonic crystals. Until now, there has been no way to make industrial-scale cheap photonic crystals. Our method is based on making plastic sphere precursors which can be heated and extruded together in such a way that they slide over each other into perfectly packed arrays. By adding tiny nano-particles (hundreds of times smaller in size) in between the spheres we can make an enormous variety of new sorts of materials or fibres which have 'smart' colour. For instance, the films are elastic and they drastically change colour when they are stretched, or are bent.In order to realise the possibilities in our discoveries, we need to find out how to properly control this shearing-assembly of polymer nanoparticles, by testing out the extrusion on a reasonable scale while measuring optically how it is taking place. We also need to develop ways to extrude fibres that could be used for making iridescent fabrics. Only when we understand the mechanisms in detail will we know enough to scale up production to the level that industry wants to see before investing further in commercial manufacture. We can also make a variety of even more intriguing films, including ones which glow with different colours, or are magnetic. We also need to show how the films might decompose to see what environmental issues might be raised by releasing such material on a widespread basis. Finally we need to develop a plan for which particular applications that we should concentrate on, in collaboration with a number of large companies.Everyone who we show these rubbery iridescent films to, wants a piece to take away with them. We want to be able to provide films to everyone, by commercialising our nanomaterials research and development.

The use of colour in every consumer product is ubiquitous. However with increasing concern for the environment, the use of traditional dyes is becoming problematic. This has opened up new opportunities in producing colour by carving out materials at scales smaller than a millionth of a metre, built of components which are benign. In addition, the new possibilities available for structural colours (iridescent, prismatic, multi-hue, or luminescent) are universally attractive in competitive marketplaces such as mobile electronics, fashion, and automotive/airline industries.We have invented a new process for making plastic films which have appealing structural colours, that can be scaled up to industrial production levels. It is based on making periodic arrangements of stacked nano-spheres with a different optical density to their surroundings, called 3D photonic crystals. Until now, there has been no way to make industrial-scale cheap photonic crystals. Our method is based on making plastic sphere precursors which can be heated and extruded together in such a way that they slide over each other into perfectly packed arrays. By adding tiny nano-particles (hundreds of times smaller in size) in between the spheres we can make an enormous variety of new sorts of materials or fibres which have 'smart' colour. For instance, the films are elastic and they drastically change colour when they are stretched, or are bent.In order to realise the possibilities in our discoveries, we need to find out how to properly control this shearing-assembly of polymer nanoparticles, by testing out the extrusion on a reasonable scale while measuring optically how it is taking place. We also need to develop ways to extrude fibres that could be used for making iridescent fabrics. Only when we understand the mechanisms in detail will we know enough to scale up production to the level that industry wants to see before investing further in commercial manufacture. We can also make a variety of even more intriguing films, including ones which glow with different colours, or are magnetic. We also need to show how the films might decompose to see what environmental issues might be raised by releasing such material on a widespread basis. Finally we need to develop a plan for which particular applications that we should concentrate on, in collaboration with a number of large companies.Everyone who we show these rubbery iridescent films to, wants a piece to take away with them. We want to be able to provide films to everyone, by commercialising our nanomaterials research and development.