CRC 951/2: Hybrid Inorganic/Organic Systems for Opto-Electronics (HIOS)

The ability to precisely control the formation of heterostructures from different materials has revolutionized electronic and optical technologies during the past decades. However, tackling the increasing challenges faced by these key technologies requires radically new approaches. In this spirit, the CRC has launched a both ground breaking and comprehensive research programme combining three significantly different classes of materials in hybrid inorganic/organic systems (HIOS) with the aim of realizing substantially improved and potentially novel opto-electronic functionalities: inorganic semiconductors feature high charge carrier mobilities, conjugated organic molecules exhibit strong light-matter coupling, while metal nanostructures excel at confining and guiding light at subwavelength dimensions. Each material class can conceivably contribute unique properties, and their merger had not been systematically attempted. For fully harnessing this potential, the CRC elucidated the fundamental chemical, electronic, photonic, and plasmonic interactions arising from the different nature of the components combined in HIOS, and uncovered novel hybridized quantum states and coupled excitations at their interfaces. In hand with this, we comprehended the limitations of state-of-the-art bulk inorganic semiconductors for achieving intimate coupling with conjugated molecules. Due to ubiquitous surface states and band bending from the surface into the semiconductor bulk, a passive interlayer compromises functionality.In the upcoming funding period, we will exploit the extremely high surface-to-volume ratio and strong light-matter interaction of atomically thin transition metal dichalcogenide monolayers, which emerged during the second funding period as ideal inorganic semiconductor component for the goals of the CRC. These monolayers feature superior structural quality and stability compared to previously used semiconductors. The fact that we can now realise HIOS that are comprised of the active region only, i.e., the interface, provides novel opportunities that were not realistically imaginable before. We now set out to achieve ultimate coupling and functionality. Furthermore, because we have access to nanometre thin, interface-only HIOS we can unleash the full potential of metal nanostructures for plasmonic enhancement of light absorption and emission by several orders of magnitude. Combined with new generations of our unique molecular photoswitches, the extensive know-how gathered within the CRC 951 enables us to realise advanced HIOS that will pave the way for unequalled nanoscale solid-state devices, not achievable with any of the individual material classes alone. Now within reach, these ultra-compact devices will feature superior functionality, such as high modulation frequency light emission and sensing, widely tuneable quantum emission, chirality sensing, electronic and optical multi-functionality, and even synapse and neuron Emulation.