Periodic Reporting for period 4 - BILUM (Novel applications based on organic biluminescence)
Berichtszeitraum: 2020-10-01 bis 2021-10-31
1. A detailed understanding of the interplay between fluorescence & phosphorescence in thin film biluminescence samples. It is observed that the long-living nature of the phosphorescence leads to very high triplet state populations that give rise to saturation and bimolecular interactions.
2. The development of transparent programmable organic luminescent tags (PLTs). This is a new technology developed in BILUM that allows for non-contact writing and erasing of information in thin film samples comprising biluminescent emitters.
3. The development of new biluminescent emitters (through design and synthesis) that allow for excitation using blue light. This is a key advance compared to UV-absorbing materials as the use of widely available blue and white LEDs as excitation sources is now possible.
4. The demonstration & detailed explanation of dual state energy transfer from a biluminescent donor material to a fluorescent acceptor molecule. Here, for both donor states (singlet and triplet), Förster Resonant Energy Transfer (FRET) takes place. Interestingly, and shown for the first time, the transfers happen from exactly the same molecular species but are separated by more than eight orders of magnitude in lifetime.
5. The realization of the continuous wave operation of the PLTs, which is possible by using emitter materials with a very high phosphorescence contribution to the overall luminescence. Here, the imprinted information can be read out under illumination, which is much more accessible as the time-gated read-out of the first demonstration.
6. The realization of sub-second programming times for the PLTs.
7. The development of a numerical model to describe the oxygen diffusion in PLTs. This model has been tested with experimental results obtained from PLTs directly (luminescence imaging) and can now be used to predict other materials systems.
8. The development of a wavelength sensing device that is able to detect monochromatic radiation with sub-nanometer precision. Here, the central element of this sensing device is a biluminescence/fluorescence hybrid system that produces a wavelength-specific signal fingerprint in the time-domain that can be read out with a conventional photo detector.
The development of the PLTs open up various new research and development directions. We have transferred this concept to be used as UV-dosimetry system and are currently planning a spin-off company based on the underlying technology. For this, we have been able to secure IP for the core technology. Apart from the dosimetry application, the PLTs have been used in proof-of-concept food packaging that can be re-used in a collaboration with a product design student. For the wavelength sensing device, we have filed a patent application. All major research results have been presented at scientific conferences and published in peer-review journals. The PLTs have been promoted through a press release that has attracted worldwide attention both from academia and industry.
- We have gathered a detailed understanding of the dynamic range of biluminescence emitters with their vastly different excited state lifetimes of singlet and triplet states. Knowing these details, it is easier to design applications and tailor new materials to meet certain application needs.
- We have designed more than 10 new organic compounds that show room temperature phosphorescence along with the conventional fluorescence.
- With our study on Förster Resonant Energy Transfer originating from emissive singlet AND triplet states, we have added to the overall understanding of energy transfer mechanisms in multichromophore systems.
- For room temperature phosphorescence (RTP), we have developed 3 specific application concepts that make use of the unique RTP properties having very persistent emission. Those are: programmable luminescent tags, UV dosimeters, wavelength sensors. All of which have not been suggested in literature beforehand.
- One finding that is not fully investigated and will keep us interested beyond BILUM is the observation of RTP of thin films immersed in aqaueous solutions. Typically one assumes that the water environment also contributes to very efficient RTP quenching. This is a surprising results that we will continue to study in the near future. It may open up the application of RTP systems to biological environments.