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.

Energy harvesting technologies collect various forms of ambient energies such as heat, light, or vibrations to generate electricity at micro scales. [1,2] Provided that the wasted energy dissipated in the environment is ubiquitous, energy harvesters present the potential to be self-sustaining with an ideal infinite functioning lifetime. Therefore, they have been considered a potential alternative to the traditional battery-based energy solutions presently enforced to energize electronic consumer goods, the Internet of Things (IoT), or other distributed electronic-based ecosystems. [3,4] Since many of these electronic devices are typically located inside buildings, there is great potential for energizing them via integrating photovoltaics (PVs) that can harvest abundantly available ambient indoor light energy from LED, halogen, and FL lamps or other types of light sources. This promising approach can be used to achieve sustainability within portable electronic devices, as well as in advanced-distributed electronic environments. [3,[5][6][7][8][9] Keeping this motivation in mind, established silicon (Si) solar cell-based PV technologies have initially been deployed to harvest ambient light energy for energizing various low-powered electronic appliances such as calculators, digital thermometers, and electronic clocks. [10] However, the low power conversion efficiency under lowlight conditions, combined with high production costs have limited their widespread use in indoor applications. [7,8,11] In contrast to Si-based PVs, third-generation-based solar cell technologies such as organic solar cells (OSC) or dye-sensitized solar cells (DSSC) have shown striking performance with higher conversion efficiencies when tested under indoor light conditions. [12][13][14][15][16][17][18][19] Similar to these third-generation-based PV technologies, the escalating conversion efficiencies of perovskite solar cells (PSCs) under standard illumination conditions [20,21] consequently motivated research labs worldwide to also examine their PV performance under various ambient light intensities. [6,[22][23][24][25][26] As expected, the striking conversion efficiencies of PSCs achieved in recent years (Table 1) under these ambient light intensity conditions provide preliminary evidence for considering them as another potential light-harvesting solution for energizing

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