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New colorful plastic films for versatile sensors and electronic displays

Researchers made plastic films that give an uncommon response upon binding to certain anions

April 15, 2024
Osaka University
Researchers have synthesized triarylborane (TAB) compounds that exhibit unusual optical responses upon binding to certain anions. They also synthesized thin polymer films that incorporate the TAB and retain the sensing as well as the light emission properties of the TAB. This work is an important advance in plastic research and has applications in analyte sensing as well as electronic display technologies.

Innovative electronics is one of the many applications of modern plastics. Some recent research efforts have used plastic to improve the color realism of display technologies.

Now, in a study recently published in Angewandte Chemie International Edition, researchers from Osaka University and collaborating partners have developed a borane molecule that exhibits unusual light emission upon binding to fluoride. Incorporating their molecule into common plastic is straightforward, resulting in versatile materials for electronic display and chemical sensing applications.

A class of molecules known as triarylboranes (TABs) has photochemical properties that are useful in optics. For example, upon binding to an anion such as fluoride, disruption of the TAB electronic structure often does two things to the light emission: shortens the wavelength (blue-shift) and reduces the intensity (turn-off response). Lengthening the emission wavelength (red-shift) is nearly unprecedented because corresponding design principles are unavailable. Developing a new class of TAB that exhibits a red-shifted sensing response, and can be easily incorporated into plastic electronics and similar technologies, is the problem the researchers aimed to address.

"Our borane-based sensor exhibits a red-shifted response upon binding to an anion such as fluoride," explains Nae Aota, lead author of the study. "Our method is based on reducing orbital energy gap of the molecule in the ground state and enhancing charge-transfer in the excited state by reversing the role of TAB from electronic acceptor to donor."

A highlight of the researchers' work is facile incorporation of a TAB-fluoride into polystyrene and poly(methyl methacrylate) polymer films. The polymer matrix did not impair the red-shifted light emission. In fact, one film exhibited warm white light -- a highly desired property that mimics sunlight. Furthermore, the color of the light emission was finely tunable by simply adjusting the quantity of added fluoride.

"We're excited by the versatility of our thin films," says Youhei Takeda, senior author. "We can use the bipolarity of the phenazaboride to prepare plastic films ranging from blue to near-infrared, for displays and ultra-sensitive anion detection."

This work is an important step forward in electronic display technologies. Furthermore, by tuning the selectivity of the TAB to anion binding (i.e., detecting only one type of anion even in the presence of other potentially competing anions), applications to highly sought sensing technologies will be straightforward.

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Materials provided by Osaka University. Note: Content may be edited for style and length.

Journal Reference:

  1. Nae Aota, Riku Nakagawa, Leonardo Evaristo de Sousa, Norimitsu Tohnai, Satoshi Minakata, Piotr de Silva, Youhei Takeda. Anion‐Responsive Colorimetric and Fluorometric Red‐Shift in Triarylborane Derivatives: Dual Role of Phenazaborine as Lewis Acid and Electron Donor. Angewandte Chemie International Edition, 2024; DOI: 10.1002/anie.202405158

Cite This Page:

Osaka University. "New colorful plastic films for versatile sensors and electronic displays." ScienceDaily. ScienceDaily, 15 April 2024. <>.
Osaka University. (2024, April 15). New colorful plastic films for versatile sensors and electronic displays. ScienceDaily. Retrieved May 25, 2024 from
Osaka University. "New colorful plastic films for versatile sensors and electronic displays." ScienceDaily. (accessed May 25, 2024).

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