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Scientists reveal new rainbow-emitting materials

"Our molecule could become a basis for efficient light-emitting devices and pressure- and temperature-responsive sensors in the future," researcher Youhei Takeda said.

By Brooks Hays
Researchers have designed a new material that emits a range of colors when subjected to temperature and pressure changes. Photo by Youhei Takeda
Researchers have designed a new material that emits a range of colors when subjected to temperature and pressure changes. Photo by Youhei Takeda

Feb. 27 (UPI) -- Scientists at Osaka University in Japan have developed materials that emit a full range of colors. Until now, mechanochromic luminescent, or MCL, materials were only able to emit two colors.

MCL materials produce different colors by switching between stable and metastable states. To get MCL materials to emit more colors, scientists had to develop a material with more metastable states. To do so, researchers designed a new molecule.

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The new molecule combines conformationally-switchable phenothiazine, or PTZ, an electron donor, with dibenzophenazine, DBPHZ, an electron acceptor.

"In this structure, the PTZ moiety could take two distinct conformers, which therefore in principle creates in total four metastable states as a whole molecule," Youhei Takeda, a professor of chemical engineering at Osaka, said in a news release.

Tests showed the molecule responds to heating, fuming and grinding by rotating its color between yellow, red and orange. Temperature and pressure changes caused the molecule's components to alter the way they conform to one another.

The material was successfully incorporated into organic light-emitting diode devices, or OLEDs. Importantly, the material also exhibited thermally activated delayed fluorescence properties, TADF. Researchers hope to begin replacing OLED technologies, which require the use of rare metals, with more efficient TADF light emitting devices.

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"Our molecule could become a basis for efficient light-emitting devices and pressure- and temperature-responsive sensors in the future," Takeda said.

The new research was published in the journal Chemical Science.

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