A metal-free organic 3-bromo-2-thienyl diketone exhibits fast and efficient room-temperature phosphorescence with high color purity under a variety of conditions, according to a new study led by chemists at Osaka University.
Artist's impression of fast phosphorescence. A beam of blue light enters the molecule, producing a thick yellow pillar, illustrating the acceleration of phosphorescence due to the mixing of singlet states. Image courtesy of YAP Co Ltd.
“Phosphorescence is a valuable optical feature used in applications such as OLEDs and cancer diagnostics,” said chemist Yosuke Tani of Osaka University and his colleagues.
“Until now, achieving highly efficient phosphorescence without using rare metals such as iridium or platinum has been a major challenge.”
“Phosphorescence, which occurs when a molecule goes from a high-energy state to a low-energy state, often competes with non-radiative processes where the molecule loses energy as heat,” the researchers added.
“This competition can slow down phosphorescence and make it less efficient.”
“Previous studies have shown that incorporating certain structural elements into organic molecules could make them phosphoresce faster, but these efforts have not matched the speed and efficiency of rare-metal-based materials.”
“Our breakthrough with thienyl diketones represents a major advance in this field.”
Dr. Tani and his co-authors were able to observe efficient narrowband room-temperature phosphorescence from 3-bromo-2-thienyl diketone in solution, amorphous polymer matrices, and crystalline solids.
“We discovered these molecules by chance and initially didn't understand why they performed so well,” Dr. Tani said.
“But as the research progressed, the pieces started to come together and we began to understand more.”
“Our work has led to a clearer understanding of the mechanisms behind the molecule's performance than any other organic phosphorescent material to date.”
“Still, we believe there is much more to explore and are excited about the potential applications.”
“This work provides new design guidelines for developing rare-metal-free organic phosphorescent materials, which have the potential to surpass and replace these materials in a variety of applications,” the authors conclude.
“The results of this research are expected to lead to major advances in areas such as OLEDs, lighting and medical diagnostics.”
This discovery paper In the journal Chemical Sciences.
_____
Yosuke Tani othersFast and efficient narrowband room-temperature phosphorescence from metal-free 1,2-diketones: rational design and mechanism. Chemical SciencesPublished online June 3, 2024; doi: 10.1039/D4SC02841D
Source: www.sci.news
