In order to demonstrate a better environmental footprint of BAYFLEX technology compared to the alternatives, the consortium will carry out a life cycle analysis (LCA). Initially developed in the early 1960s to understand the impact of energy consumption, LCA has grown into a recognized approach, and has spawned numerous assessment tools based on life cycle thinking. Foot printing, environmental product declarations, and product category rules are all based on similar approaches, and a suite of ISO standards guide LCA studies, (ISO 14040 series), foot printing standards for products (PEF, PAS 2050) and organizations (OEF, PAS 2060). LCA evaluates the environmental impact of a product or service throughout all stages of its life, from raw materials extraction to final disposal. The analysis in BAYFLEX will use an open source inventory database and scheduled workshops with experts. BAYFLEX will also contribute to these resources with its state-of-the-art technology. A comparison analysis in both the low energy impact materials and an implementation in CMOS (based on circuit simulations) will be done.
Our first workshop on sustainability was organized by Hans Kleemann and held at TUD in January. We invited Stefano Cucurachi from Leiden University to animate our workshop. Our goal was to introduce LCA analysis to all the consortium whether or not they planned to directly use the methodology. He introduced the states of a LCA analysis according to the ISO standard and explained how LCA can be used for emerging technologies. To start our LCA analysis, we decided to use a cradle to gate scenario for single devices (year 1) and also for single circuits (year 2) analysis. For our full demo (end of project), we will use a cradle to grave analysis.
TUD & CEA worked on the LCA to determine the sustainability of OTFTs and OECT technologies. They first each defined a standard fabrication protocol. Using these protocols, all the relevant data was collected from the ecoinvent database/or new entries were created for materials, flows, and units that were not yet defined. Graphs for each process to make an organic electrochemical transistor or organic field-effect transistor were thus realized. The proxy for sustainability was chosen to be the global warming potential (GWP), measured in measured in kgCO2e/devices. The analysis provides the amount of CO2 that is released during the fabrication of a single device (~2 kgCO2e /device for OECTs), including the share coming from each process. The GWP is high, but we considered the fabrication on a single device when the tools that can handle substrates up to 15cm x 15cm. Using a conservative estimation (including contact pads), up to 3600 OECTs could be integrated on such a substrate size, resulting in a sub-gram GWP of a single OECT. Without contact pads, the number of OECTs could be much higher (<100 000). For OTFTs, 4 foils containing 11250 OTFTs were found to release 26.1 kgCO2e.
STAY TUNED! Next year we will provide our analysis for circuits of OTFT and OECT technologies.