Abstracts

The research in organic semiconductors is a key element to boost the development of new devices enabling new commercial applications in the field of Organic Electronics (OE), such as the production of cold light for lighting environments and car panels, transistors, photovoltaic cells, sensors, and flexible devices. OLEDs, that derive their name from the organic molecules used to produce light through the phenomenon of electroluminescence, have been developed to the point that they have become a mainstream display technology for mobile devices and televisions. However, organic electroluminescence can also be used for applications beyond the more fascinating world of displays. Organic Up-converter Devices (OUDs), for example, have attracted considerable research interest due to potential applications in optical communications, biomedical applications, night vision, biological imaging, telemetry and security. The OUD consists in a tandem structure with NIR sensitive organic photodetector (OPD) stacked in an efficient visible OLED. In the dark the device is in the off-state. When NIR light is absorbed by the PD, electron-hole pairs are formed. Under the appropriate bias, holes are driven into the OLED where they recombine with electrons injected from the cathode, thus leading to light emission. OLEDs can be used also as flexible and biocompatible light sources for photodynamic therapy (PDT). The PDT mechanism is non-invasive treatment for surface lesions, such as human skin, which uses visible light to excite a photosensitizer (PS), which is a photosensitive drug. The PS molecule in its ground state can absorb a photon and pass to its excited state and, at the end of this process, reactive oxygen species, mainly singlet oxygen, are produced. The oxygen produced is reactive and can destroy nearby cells such as bacteria, fungi, and tumor cells. In this presentation, we will describe the challenges and opportunities in the OLEDs applications described above.