In BILUM, organic small molecules are investigated that show simultaneous fluorescence & phosphorescence with high efficiency at room temperature. This turns these molecules into dual state, or as we call them, biluminescent emitters. The emission shows two characteristic emission band, split by the eneretic splitting between singlet (fluorescence) & triplet (phosphorescence) states. The fluorescence has typical decay times in the ns range, whereas the phosphorescence is a quantum mechanically forbidden transition, rendering it slow with ms decay times. It is the main objective to investigate this biluminescence in detail to be able to exploit these unique properties in novel applications. BILUM is structured in different research directions (RDs). In RD-A, the weakly emitting phosphorescence is the central focus. We want to understand the nature of this phosphorescence, its limitations & potential to be further increased and adjusted to possible applications. In RD-B, we investigate effects of high population densities in such biluminescent emitters. This is central, as the phosphorescent lifetimes with ms values will inherently lead to saturation effects and, thus, dictate a delicate interplay between fluorescence and phosphorescence. In RD-C, we explore biluminescence systems as sensing platforms. Here especially oxygen sensing is easily possible, as the phosphorescence is highly oxygen sensitive. With the addition of the second fluorescence channel, such biluminescence emitters intrinsically sport a reference signal. Finally in RD-D, we utilize all or knowledge from RD-A to RD-C to design and synthesize novel biluminescent emitters. Here, the specifications are determined by the joint insights of the project and the targeted applications. Conclusions: All main objectives of BILUM have been successfully addressed. We have developed a deep understanding of the basic working mechanism of biluminescence, have developed and learned to understand even new materials and material systems, have pursued new applications in form of different sensor concepts and programmable luminescent tags. The latter can be used as dosimetry systems to quantify UV radiation, which is very important in the current UV desinfection markets.
