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

随着电信网络承载的业务量急剧增加，对无线资源(频谱)的需求迅速超过了其有限的供应。在高密度用户场景中，由于频谱拥塞导致的服务质量严重恶化，其中用户需求导致接入受限。在室内应用中，这个问题更严重，因为缺乏频谱和大量用户会导致显著的网络减速。据估计，70%以上的无线流量发生在室内环境(家庭/办公室等)。因此，需要可靠的低成本、高容量无线技术来确保始终无缝的室内无线连接。可见光通信(VLC)使用可见光频段(~400 THz)提供无线连接，这是一种具有高安全性的无许可证频谱，其光源用于提供照明。VLC使用半导体发光二极管(LED)，可以高速调制，同时提供恒定的照明水平。传统上，VLC使用无机LED作为其发射器的光源。这种器件带来了尚未解决的重大缺陷，例如由于昂贵的易碎和复杂的外延处理方法而无法生产大型面板。此外，为了提供适当的照明，需要器件矩阵，因此引入了显著的电路复杂性。其他缺点包括无法使用对移动设备有吸引力的柔性衬底，以及难以制造固有不同波长的设备。所有这些缺点都可以通过用有机聚合物取代常用的无机金属作为LED的半导体材料来解决。聚合物LED(PLED)可以在室温下使用廉价的湿处理方法(如喷墨打印)来制造，从而以极低的成本生产具有较大光活性面积的单面板设备。此外，PLED可以沉积在各种不同形状的衬底材料上，从而开发出新一代器件。通过一种简单的制造工艺(一步沉积不同的有机聚合物)，PLED可以被设计成产生红、绿、蓝(RGB)光，然后组合在一起，实现照明和信号传输的双重功能。在过去的十年里，申请这一资助的团队共同展示了在VLC系统中使用有机(聚合物)LED的重大成功，具有制造、成本和操作优势。我们之前的工作在传输信号质量和比特率方面取得了几个“世界第一”，我们的成果发表在领先的国际期刊和会议上。在这项提案中，我们将建立在我们三个团队财团的现有优势和不同专业知识的基础上。具体地说，我们在无机半导体、光学元件设计和制造、电子电路设计和通信系统集成方面的研究将用于构建和演示基于PLED的VLC概念验证系统，其中包括新的器件、电路和系统设计。我们希望在现实的室内环境中实现前所未有的VLC传输速度。该项目将研究设计PLED的新方法和新的光学技术，以最大化其光效。将研究新的电路和通信工程技术，以允许电子电路与PLED的优化耦合，克服一些PLED固有的数据承载限制。我们的目标是组装一个完整的系统，并在VLC特别设计的测试室中进行测试。总之，我们认为这项工作非常及时，因为它解决了两个关键挑战：设计在免许可证频段运行的系统，以及提供易于制造和低成本的有机光电子器件。

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.