Electrochromic Gels for Smart Windows (ChromGels)

It has been shown that large office buildings waste 20-40% of their energy on air-conditioning to cool down the building as a result of the sun. This is highly inefficient and has an impact on the environment. One way that has been proposed to tackle this problem is the use of Smart Windows. These windows are comprised of chromic materials that change to a dark colour upon the application an external stimulus. The change in colour results in high energy UV light that heats up the building being filtered out, thus reducing the need for air-conditioning. It is predicted that these technologies will save 20% on their energy bills, as the buildings will not heat up as much from the sunlight. However, so far this transparent-to-dark colour has been difficult to achieve. Suitable materials for Smart Glass that can change colour can be metal-based, organic-based or a hybrid of the two. Metal-based chromics are already used in displays and diagnostic tests. However, precious metals (Au and Ag) used in these high-end technologies is a rapidly running out resource, and are often difficult and dangerous to mine, and their use relies on countries cooperating well with each other. The processing of metals such as Cd, Lb, U and Cs has huge environmental consequences and the disposal of them leads to toxic and nuclear waste which has devastating effects on the workers, neighbouring villages and wildlife. Any metals that can be replaced with organic alternatives have a huge benefit to health, the economy and the environment. Organic materials are generally easier to process and can be synthesised on a larger scale. We have found a molecule based on a functionalised naphthalene diimide that when self-assembled in water shows great promise to be used in such applications. From proof of principle data we have collected, the assembled material can undergo a reversible transparent to black transition by applying a small voltage to the sample. This transition is quick and can be cycled at least 100 times without loss of colour intensity or response time. However, this system needs optimising to be able to fulfil industry standards, for example stability over 1000 cycles, reducing the speed of response of both transitions and the uniformity of colour across the device. We aim to do this with this proposal to make the organic alternative to metal systems competitive to use in the Smart Window technology.

The ultimate aim for the impact of this project would be on the environment. By using these organic alternatives to metal-based materials this would reduce our dependence on these expensive and environmentally damaging metals. By not using metals in the devices, we will also reduce the cost of the production and processing costs and so therefore reduce the overall cost to the consumer to buy this technology. This cheaper cost would allow the devices to be used more widely in building as they would be more cost effective and accessible. This means potential reduction in air conditioning in large office building to cool them down which is currently needed to cool them down from heating up from the sun through the windows. Overall, this will lead to more sustainable cities and futures.

By showing that organic alternatives to metal can compete with their metal-based competitors this could lead to more research being dedicated to finding organic based alternatives to metals in other technologies such as renewable energy, so further reducing the use of metal in technology.

If the technology were commercialised as hoped, this would create new jobs within the company to develop the technology into actual working windows. The new product and the multi responsiveness of the materials gives the company a unique product and so potentially would make the company a lot of money. This is due to the materials being so cheap to produce and very little processing. By keeping the cost down, it also allows it to be more affordable to consumers. By installing the windows in homes or offices, they are able to reduce the need for air-conditioning and so reducing the running costs of buildings and the saving energy. The money saved through this makes the windows essentially pay for themselves in the long run.

There will also be impact for the PDRA and PI on this project. Both the PDRA and PI will have the chance to interact with industry and see how they work and get the chance to meet engineers and technology experts who can bring technologies to the market. This is invaluable and such knowledge can be applied to future grant applications as the most important industrial aspects rather than just academic can be thoroughly considered due to having experience of working in both environments. The PDRA will gain experience not only with any new techniques they may learn either in the PI's lab or in the lab or our collaborator (Walsh), but will also gain industrial lab experience. This will give them the chance of working in industry which most PDRA researchers do not get the chance to do and will help them make decisions of what career path they would like to pursue in the future. The PDRA will also present at conferences and will learn essential communication skills and build confidence from networking from attending these events