# Measurement of Visible Radiation through a _Sansevieria cylindrica_-Based \"Living Sensor\"
## 1 Introduction  
The extensive use of natural resources and the adoption of industrial processes and fabrication procedures have led to an increase of greenhouse gases and emissions in the atmosphere, causing global climate change [1; 2; 3]. Terms such as net-zero carbon dioxide emissions, carbon-neutral, and climate-neutral are used to describe a global target which regards carbon offsetting or the elimination of emissions from society [4; 5]. This transition regards various aspects, fields, and scientific disciplines in the applied science [6]. Focusing attention on microelectronic devices, it must be observed that these technological solutions require vast amounts of power during the production process, such as the melting/purification of raw silicon, diffusion furnaces, plasma-etching machines, material deposition onto Si-wafers, etc. [7; 8; 9]. These days, the common goal is the development of micro-scale devices (such as MEMS or NEMS systems) capable of being used as sensors, transducers, operation circuits, and data decoding or transmission devices [10; 11; 12] for variegated applications ranging from industry to agriculture, cultural heritage, and security [13]. Such electronic systems have low costs, so they are massively produced by industries. Certainly, the budget of anelectronic device should also account for the impact on the environment when such devices are produced and, even more, when such devices must be disposed [14]. It should be considered that silicon-based solutions cause environmental pollution with CO2 emissions during manufacturing, and problems of non-biodegradability and toxicity at the dissemination or end-of-life step [15]. The CO2 issue arouses particular interest considering that the quantities present in the air may also be harmful to the environment and to humans. Furthermore, e-waste production and the disposal of exhausted electronics after their end of life is a big environmental issue and the contribution of emissions also strongly includes foundries and the disposal processes of silicon-based devices [16]. This amount of produced pollutants exceeds any other industrial production, including the giant automotive and car production. From the perspective of reducing carbon emissions and the energy budget during fabrication, several chipmakers, semiconductor industries, and silicon foundries started various actions to ensure a massive reduction of emissions [17]. Considering the difficulty of sustainable approaches in conventional electronics, the trend is in the direction of non-silicon electronic components of circuits, sensors, and transducers [18]. A clear tendency is shown in the literature to use polymers or biomaterials to fabricate devices, with the goal that they will be environmentally friendly [19; 20]. Using some of these materials, it is possible to implement organic light-emitting diodes (OLEDs), organic field-effect transistors (OFETs), both the n-type and the p-type; and transducers and converters based on polymeric substrates such as polyethylene terephthalate (PET) or polycarbonate (PC) [21; 22]. The evolution of green sensors can be found in [18], where the authors present solutions capable of implementing the next generation of green electro-active polymers for active substrate and motion transducers. Such materials, as described in the case of sensors, make organic electronics greener, although small amounts of materials do not make it totally green. Such solutions, both at the sensor and electronic components level, lead to a CO2 emission equal to almost zero and a biodegradation < 100%. The objective of this paper is to go beyond this technological limit and paradigm, by developing not only a sensor that is 100% biodegradable, with no CO2 emissions during the production, considering the absence of manufacture and foundry processes, but also a device that is able to absorb the CO2 already present in the environment, through its natural photosynthetic processes.