Design and implementation of a light-based IoT (LIoT) node using printed electronics

Abstract. The recent exponential growth of new radio frequency (RF) based applications such as internet of things (IoT) technology is creating a huge bandwidth demand in the already congested RF spectrum. Meanwhile, visible light communication (VLC) is emerging as a technology which can be used as an alternative wireless communications solution which makes no use of the radio spectrum. In addition, continuously powering up the massively deployed IoT nodes is becoming a challenge when it comes to maintenance costs. Development of energy autonomous IoT nodes would certainly assist to solve the energy challenge. Previous work shows that renewable energy sources can be utilized to address the energy requirement of IoT nodes. Under this context, we have developed a light-based energy autonomous IoT (LIoT) prototype. This thesis presents a feasibility study and proof of concept of LIoT, including design, implementation and validation of LIoT nodes and a transmitter unit. Furthermore, the ability of multiuser communication using VLC as well as indoor light-based energy harvesting were demonstrated and tested in this thesis. To make the concept of LIoT more attractive from an implementation standpoint, and to create a future-looking solution, printed electronics (PE) technology was used as a part of the implementation. Two key components of the prototype were based on PE technology, photovoltaic cells used to harvest energy, and displays used to exhibit information transmitted to the LIoT node. In the future, when PE technology becomes more mature, very low-cost, small form-factor and environmentally friendly LIoT nodes could be implemented on thin substrates. A wide array of possible applications can be created combining the concept of light-based IoT with printed electronics. The proposed LIoT concept shows great promise as an enabling technology for 6G

Light-based IoT:developing a full-duplex energy autonomous IoT node using printed electronics technology

Abstract The light-based Internet of things (LIoT) concept defines nodes that exploit light to (a) power up their operation by harvesting light energy and (b) provide full-duplex wireless connectivity. In this paper, we explore the LIoT concept by designing, implementing, and evaluating the communication and energy harvesting performance of a LIoT node. The use of components based on printed electronics (PE) technology is adopted in the implementation, supporting the vision of future fully printed LIoT nodes. In fact, we envision that as PE technology develops, energy-autonomous LIoT nodes will be entirely printed, resulting in cost-efficient, flexible and highly sustainable connectivity solutions that can be attached to the surface of virtually any object. However, the use of PE technology poses additional challenges to the task, as the performance of these components is typically considerably poorer than that of conventional components. In the study, printed photovoltaic cells, printed OLEDs (organic light-emitting diodes) as well as printed displays are used in the node implementation. The dual-mode operation of the proposed LIoT node is demonstrated, and its communication performance in downlink and uplink directions is evaluated. In addition, the energy harvesting system’s behaviour is studied and evaluated under different illumination scenarios and based on the results, a novel self-operating limitation aware algorithm for LIoT nodes is proposed

Performance evaluation of carbon-based printed perovskite solar cells under low-light intensity conditions

Abstract The use of photovoltaics (PVs) to harvest energy inside modern building environments has great potential for energizing a wide range of futuristic self-powered electronic devices, Internet of Things (IoT), and sensors using available ambient light. Among the various PV technologies, hole-conductor-free carbon-based printable perovskite solar cells (CPSCs) have attracted significant interest, owing to their impressive PV performance under standard full sunlight conditions, robust stability, and printable fabrication methods. Nevertheless, their ability to harvest indoor light has been rarely explored. Here we report PV performance characterization of these printable CPSCs, and a systematic comparison of their PV performance under commonly available fluorescent (FL) and light-emitting diode (LED)-based lamps at various low lux light intensities that replicate standard indoor environmental conditions. To consolidate the proven stability of these CPSCs, the results of one stability test standardized as ISOS-D-1, which supports the motivation of their possible deployment under mild indoor lighting conditions are presented. The effective functioning of these CPSCs is also demonstrated for energizing an electrical node as evidence of their potential to be used as an alternative light-harvesting solution for the targeted futuristic IoT-based ecosystem. These results greatly support the goal of developing all printed and sustainable IoT devices with robust performance stability