Increasingly, the places we inhabit and move through - our homes, stations, cafes, offices and the like - will have embedded Internet-of-Things (IoT) devices. These will enable us to be provided with content, communicate, have our environments sensed and adjusted, and so on. While this is a compelling (and very useful) future vision, the energy demands it brings are enormous. Furthermore, we risk cluttering up our physical environments with a plethora of digital devices. In the 'developed' world these are problems that will affect sustainability and the quality of our built environments. In the 'developing' world, though, energy resource constraints and physical resource issues means that without innovation, billions of people will have reduced opportunities to benefit from the coming IoT revolution.

This project is about trying to capture the benefits of the IoT future while making it sustainable, delightful and universally accessible. The work involves a team of material scientists and human computer interaction researchers, working together with partners to develop a new form of physical material that can generate the power it needs to drive digital interfaces and interactions. That is, we will drive towards attractive, flat and flexible solar energy harvesting tiles (Photovoltaic - PV - tiles), which may incorporate input and output features to enable people to interact with them and other connected devices. These tiles will be able to be integrated into buildings (in walls and floors, for instance) and objects (like tables, clothes and book covers). The surfaces capture the energy from indoor and ambient light and at the same surface can present digital displays and interfaces to the user.

To illustrate the possibilities, consider the following four user-centred scenarios:

1. Tom is busy in the kitchen. A set of Interactive-PV tiles, built decoratively into the wall along the kitchen surface, activates to show a silhouette of a figure approaching the front door. Tom is waiting for a delivery, so gestures at the tiles - the delivery driver at the entrance is shown a message on the door number PV tile, asking her to leave the parcel in the porch.

2. Shashank is walking through the narrow streets of a slum in Mumbai during the monsoon rains. He approaches an awning protecting the street from torrential rain and gestures at a flexible Interactive-PV tile woven into it. The tile displays a no-entry warning sign, and he decides to change direction to avoid walking into a deep flood in the passageway ahead.

3. Sarah has created some interactive art designs for her bedroom wall. She sends them to the Interactive-PV display tiles she has had installed, and later enjoys them, especially as they show her the external weather forecast in a personalised way. She's happy that while they work like LED displays, they can operate for years without needing external power, battery changes or space-consuming standard PV cells.

4. Sofia has flexible designer Interactive-PV tiles on her dress that she uses to control a music player or smartphone with hand gestures, and to receive alerts via electro-tactile feedback. She's impressed that the interface works in a range of environments and light conditions as she moves from her house, through the underground metro system and later to a mellow lit bar.

The project ideas and the work itself as it progresses have been co-created with UK and global industry partners and a centre in India that has over 40 years of providing insights into design for resource-constrained communities.

Potential Impact:
The predicted size of the Internet of Things (IoT) market is vast: the Blackett Review of 2014, for instance, analysed predictions of growth in devices (with a range of 22-100bn by 2020) and global economic value ($1.9-$14.4trn by 2020). The review also noted that, "The devices that enable integrated smart home services [...] will require energy to operate [...] in aggregate the Internet of Things may significantly increase electricity demand.".

Our aim in this work is to platform positive impacts on billions of people worldwide who will be users of the IoT in the future. We will do this by providing prototypes and evidence of the value and efficacy of an innovative way to provide such services; a way that is: a) sustainable from an energy consumption perspective; b) that affords elegant integration with physical environments and objects, reducing the clutter and crowding of our world with a plethora of conventional IoT gadgets; and, c) that can ensure wider access to the IoT revolution in both the 'developed' and 'developing' world due to these two other virtues. In the world changed by the technology and ideas created in this project, then, surfaces - some flat and rigid, others flexible - will be able to be used to build physical areas and objects (such as walls, floors, tables, book covers, clothes) that are useful and aesthetically pleasing in themselves and that will also be self-powering digital interactive displays.

With the basic science advances and early-stage prototypes produced by the project, the UK economy and society will directly benefit in three ways: i) by being seen to be a centre of excellence for a much sought-after set of innovations, with the inward investment - and talent pull - this will lead to; ii) by giving the UK-based cadre of IoT software and hardware developers and PV materials manufacturers a "home advantage" through early exposure to the next set of opportunities for markets both in developed and "emerging" economies; and, iii) through these channels seeing tens of millions of UK citizens purchasing and using these new devices and surfaces to enhance their productivity, well-being and delight in life. The UK is already recognised as a world-leading centre for human-computer interaction and PV research and innovation. There are a relatively few groups in the UK focusing on advances in material science to extend user experience and interaction, and none that deploy emerging user-centred approaches to innovate in PV material science itself. Our work will enhance the profile and standing of this important set of activities in the UK, developing people with skills and outlooks that can shape and take forward the opportunities that these new platforms will enable

A key focus of the Call that this project is in response to is to is to afford a transformation in the interaction between end-users - in industry and other sectors - and researchers through co-creation of the initial and ongoing research programme. Throughout the 36 months of the project, we will be engaging with our partners based in the UK and globally, a wide range of stakeholders, and the public. Our partners have been involved in shaping the proposed research and all of these parties will benefit as the work unfolds. For example, industrial attendees of our Innovation Sprints will: find new directions for their products and services; learn about the challenges of co-creation of the new materials (such as the differing timescales in low-fidelity prototyping by HCI researchers vs. fabrication time of PV tiles); and, network with a diverse set of similarly interested others. Meanwhile, our deployment communities will benefit by learning about, while shaping, technology, and having use of infrastructures that will improve their everyday experiences. In addition, through the online toolkit, and particularly the proposed Kickstarter-style initiatives, we will engage with a wider set of other society and economic actors.