TOKYO-- October 12, 2022 -- NTT Corporation (President and CEO: Akira Shimada, “NTT”) and the Graduate School of Frontier Sciences, The University of Tokyo (GSFS) have successfully produced the world's first communication signal using a battery and a circuit composed of environmentally friendly materials free of scarce elements and hazardous substances. As the Internet of Things (IoT) proliferates, all sorts of objects are being transformed into devices, expanding their range of services and applications. However, concerns exist about the environmental impact associated with the disposal of consumables converted into sensor devices. To address this issue, NTT is promoting the research and development of devices using materials that have a low environmental impact once discarded.

NTT and GSFS are exploring improvements to environmentally friendly batteries by eliminating the use of scarce materials and hazardous substances. Together, the two organizations have manufactured a new Proof of Concept (PoC) sensor device made from an environmentally friendly circuit using organic semiconductor technology and have succeeded in generating the world's first communication signal using these types of sustainable materials. This technology could be used for sensing devices in unsealing detection (e.g., in single-use water bottles), sensing devices in pill packages to determine if a patient has forgotten to take their prescribed medication or reducing the environmental impact of observational weather buoys (Figure 1).

In 2018, NTT took the first step in this development by manufacturing and verifying the battery operation of “Return-to-the-Earth-Battery” (composed of fertilizer ingredients and organic materials). Then, the collaborators interviewed experts in the field of waste management to determine what materials should be selected to achieve low environmental impact. In response, the pair eliminated materials containing scarce elements (out of consideration of resource availability) and hazardous substances (Tables 1&2).

Using these materials, researchers at NTT collaborated with Professor Junichi Takeya’s laboratory at GSFS to create an environmentally friendly circuit. Together, the researchers developed an organic transistor manufacturing process in which all electrodes are made of carbon material (carbon-electrode organic transistors) and are used to construct analog oscillation circuits and digital modulation circuits with CMOS. Researchers formed a three-dimensional conductive porous structure, applied carbon as an electrode and increased the voltage by serializing the batteries.

NTT plans to continue developing related technologies, collaborating with external organizations and companies to explore use cases unique to “low environmental impact,” and jointly implementing novel services.