Multifunctional Polymer Light-Emitting Diodes with Visible Light Communications (MARVEL)

With the dramatic increase in traffic carried by telecommunication networks, the demand for wireless resources (spectrum) is quickly outstripping its limited supply. Serious deterioration of service quality due to spectral congestion is becoming evident in high-density user scenarios, where users demand leads to a limited access. This problem is even worse in indoor applications where a lack of spectrum and a large number of users causes significant network slowdown. It is estimated that more than 70% of wireless traffic takes place in an indoor environment (home/office etc.). Thus, there is the need for reliable low-cost, high-capacity wireless technologies to ensure seamless indoor wireless connectivity at all times. Visible light communications (VLC) offers wireless connectivity using the visible band (~400 THz), which is a license free spectrum with high security and where its sources are used to provide lighting. VLC utilises semiconductor light emitting diodes (LED), which can be modulated at high speeds while providing a constant level of illumination. Traditionally, VLCs use inorganic LEDs as their transmitters' light sources. Such devices introduce significant drawbacks that have yet to be addressed, such as the inability to produce large panels due to the brittle and complex epitaxial processing methods that are expensive. Furthermore, to provide proper illumination, matrices of devices are required, thus introducing a significant circuit complexity. Other drawbacks include the inability to use flexible substrates that are attractive for mobile devices and the difficulties in producing devices with inherent different wavelengths. All of these disadvantages can be dealt with by replacing the commonly used inorganic metals by organic polymers as the semiconductor material of the LEDs. Polymer LEDs (PLEDs) can be manufactured using inexpensive wet processing methods at room temperature (such as inkjet printing) to produce single panel devices with large photoactive areas, at extremely low cost. Further, PLEDs can be deposited on a wide variety of substrate materials and with different shapes, allowing the development of a new generation of devices. Using a simple manufacturing process (one step deposition of different organic polymers) PLEDs may be designed to produce red, green and blue (RGB) light and then combined to allow the dual function of lighting and signal transmission.

Over the past decade, the teams applying for this grant have collectively demonstrated major successes in using organic (polymer) LEDs in VLC systems, with manufacturing, cost and operational advantages. Our previous work has led to several "world firsts" in terms of transmitted signal quality and bit rates, and our results were published at leading international journals and conferences.

In this proposal we will build on the existing strengths and varied expertise of our three team consortium. Specifically our research in inorganic semiconductors, optical component design and fabrication, electronic circuit design and communication systems integration, will be used to construct and demonstrate a new PLED based VLC proof of concept system, which includes novel device, circuit and system designs. We expect to achieve unprecedented VLC transmission speeds in realistic indoor environments. The project will study new methods of designing PLEDs and new optical techniques to maximise their light efficiency. New circuits and communication engineering techniques will be investigated to allow optimised coupling of electronic circuitry to PLEDs, overcoming some of PLEDs inherent data carrying limitations. We aim to assemble a complete system and test in in a specially designed test chambers of VLC.

In summary, we believe this work to be highly timely as it addresses the two key challenges; the design of systems operating in license free spectral bands and the provision of easy to manufacture and low cost organic optoelectronic devices.

We hope that the leading work on inorganic devices in the UK will be strongly complemented by this work, to the benefit of the UK's leading standing in this fast developing area.

the scope and impact of MARVEL is broad. The research will not only develop the required technologies to reach its multiple goals but also it will look into creating new business opportunities based on VLC in an important number of practical scenarios. In fact, home, office and public places, are basic scenarios where the technology developed in MARVEL can be applied. As people spend most of their time in such places, the impact of this work on users is potentially high. The impact of of this research on operators, equipment manufacturers (mobile devices and infrastructure), standardization bodies and regulators is expected to be high.

Academically, the knowledge attained in modelling, design, simulations, implementation and processing of PLED based VLC networks will be invaluable in extending the interdisciplinary expertise of the research associates. The EPSRC and UK government has listed conductive polymer technologies as an area for significant growth and this proposal directly supports these claims and enables improved UK competitiveness in the display technology sector with a unique interdisciplinary project. Furthermore the European Union Horizon 2020 programme has identified organic technologies as an area for growth, and allocated at least 30m Euros for research funding.

Economic and societal: VLC in networking is well suited for a number of applications including a replacement for standard Wi-Fi deployment in local area networks in indoor environments; in areas where Wi-Fi networks are not practical or may cause harm due to electromagnetic interference from the Wi-Fi system or it causing issues with in-room equipment, such as a hospital setting; in home area networks to communicate with appliances and automatic home systems; car-to-car communications; underwater communications systems between various manned and unmanned platforms; for communication between handheld devices; as an enabler for local positioning systems. This introduces a huge market opportunity for the VLC in addition to posing a technical challenge, since the current RF based mobile systems cannot support all these requirements. Therefore, the adoption of VLC technologies can give rise to new business ecosystems, characterised by new actors and value chains. This research will assist in making this to become a reality, since our results would demonstrate white LED cab be used in a wide scale allowing communications as well as illumination with minimum energy usage, high performance and high data rates. Therefore, this research will provide economic and societal benefits within a few years in the UK as well as worldwide,

Knowledge and training: We plan to disseminate our findings to a much wider community including the lighting industries, telecommunication network service provider, in the UK and the rest of the world.
The proposed research will offer personal development for the research team. researchers will be mentored by the PIs and CoIs, who between them have proven track records in of nurturing close 50 early-career researchers to reach their full potential. Furthermore, RAs will be able to draw upon the investigators considerable technical expertise and experience. Furthermore, PhD students (funded by the universities) will work in this area and related areas and will be trained in optoelectronic and VLC systems design as well as in practical techniques. We believe such training will provide the necessary skills for furthering the UK's standing in this area in industry and academia.