Nowadays OLEDs are the big success story of organic electronics, and you may already use them as part of OLED displays in TVs and smartphones. However, the first organic-based electronic device was the thin-film transistor (TFT). Afterward, organic-based TFTs are fabricated by ink-jet printing in a variety of large-area substrates, including textiles, and plastics substrates. Applications being developed include among others, flexible displays, large-area sensors, and radio frequency identification tags. Yet, in the early times, organic-based TFTs were unstable due to threshold voltage instability.
Our team identified the physical origin of this instability, and our work in this field is today a reference that led to worldwide research in strategies to passivate electrical active impurities in TFTs. The group of organic electronics made a crucial contribution to the commercial development of transistor devices.
Currently, the organic electronics team is positioning its research in what is believed the next big revolution in organic electronics, Bioelectronics. Organic bioelectronic devices can be used to translate biological signals and promote the regeneration of biological tissues and even repair faulty nervous connections. In fact, organic semiconductors have the unique capability to translate both ionic and electronic signals. Furthermore, they are soft materials, flexible, and easy to operate in liquid environments. Motivated by the need for new tools and techniques for human therapies and healthcare there is intense research targeting medical applications, such as diagnostics and therapy, and also some niches in cell biology, such as monitoring or controlling the growth of cell cultures.
In this emergent field, the organic electronics group is actively pursuing the development of implantable devices that can record the bioelectrical activity of cancer cells and tumors. Our long-term goal is to decode the bioelectrical language of tumors. Once this cell-cell bioelectrical communication is decoded we can use our electronic devices to send artificially generated instructions that in principle can overdrive the cancer cell instructions and impede the spread and invasion of nearby healthy tissues by the cancer cells. Similar devices have also been developed by us to decode cell bioelectrical activity when skin wounds are repaired.
In the coming years, we foresee the development of a disrupted generation of organic bioelectrical devices that can help in the repair of tissue injuries and other diseases. Towards that end, we made recently important steps. Our team developed the first ultra-low noise devices capable to measure faint bioelectrical signals generated by populations of non-nervous cells, these include dermal (skin) cells and cancer cells.
In analogy to the development of communication, sensor, and actuator technology developed for the automotive industry, it is foreseen that diagnostics, monitoring, and even therapy will be autonomous and carried out beyond the walls of the hospital. Bioelectronics will have a major impact on society. It is also expected that organic electronics will explore other fields of application not only restricted to healthcare applications.
Organic electronics can interact with plants, and with microorganisms such as bacteria, fungi, and algae. As an example, in this area, our team together with an international consortium has recently proposed a symbiotic electronic device made of algae and an organic transistor. In this symbiotic device, a carpet of living algae is printed on top of a large area gate terminal of the transistor. The algae population generates by photosynthesis electrical charges that are then transduced into an electrical current by an array of organic transistors. The device can be made to float on the ocean surface and generate electricity for remote and stand-alone applications.
 P. M. C. Inácio et al., “Ultra-low noise PEDOT: PSS electrodes on bacterial cellulose: A sensor to access bioelectrical signals in non-electrogenic cells,” Organic Electronics, vol. 85, no. June, 2020, DOI: 10.1016/j.orgel.2020.105882.
Organics Electronics Group at IT: