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Luminescent compounds with Delayed Fluorescence in Aggregate State for Imaging Applications

Year: 2022
Type: dissertation
Abstract: Visual stimulation through colour is one of the most powerful tools to get and process information easily. In the world of chemical compounds, this type of knowledge could be reached using fluorescence. However, a major disadvantage of this process is its small lifetime that can limit, for example, the local cell-imaging information using conventional fluorescent probes. To overcome this problem, TADF (Thermally Activated Delayed Fluorescence) com pounds are a possible solution since their lifetime range could reach micro- or even milliseconds. TADF compounds were firstly recognized for their ability to maximize internal quantum efficiency of OLEDs but now they are also known for their capacity of bioluminescent probing. The major concerns of using TADF compounds in biologic systems are their low solubility, low biocompatibility, poor efficiency in polar media and high susceptibility to oxygen in triplet state. Therefore, we designed a series of com pounds which can exhibit TADF in the aggregate state - Aggregation Induced Delayed Fluorescence (AIDF), as a possible solution to overcome these limitations. For the aim of this work, Diphenyl sulfoxide-based and Quinoxaline-based units acceptors and its relatives were synthetised with success. Diphenyl sulfoxide derivatives were confirmed unstable towards fluorescence irradia tion. As a consequence of that, TADF was not able to be confirmed. However, diphenyl sulfoxide derivatives have shown signs of AEE (Aggregation enhanced emission). Nonetheless, the presence of aggregate states has been observed. A quinoxaline deriva tive was also studied. In this case, the TADF and aggregate states phenomenons have been experimentally verified. And, instead of AIE-TADF, AEE-TADF was confirmed.
Language: English
Open Access status: green
OpenAlex ID: W7039052264
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