Toray Industries, Inc.
Tokyo, Japan, March 24, 2023 – Toray Industries, Inc., announced today that it has won a Chemical Society of Japan Award for Young Chemists in Technical Development for 2022. This award recognized Toray for developing significantly more stable organic phosphors delivering high color purity and efficiency and creating eco-friendly, nontoxic color conversion sheets that employ the phosphors for liquid crystal displays (LCDs) with wider color gamuts.
Organic phosphors convert energy into light. They serve as fluorescent labels and sensitizers because they offer superior design flexibility and luminescence. Recent years have seen research into applying them to electronics and information, energy, and other advanced fields. The downside has been that organic phosphors have been less stable than inorganic counterparts, frequently impeding practical applications.
It is worth noting that while smartphones and other small devices increasing employ organic electroluminescent displays, monitors, televisions, and other medium- and large-sized displays are predominantly LCDs. Wider color gamuts are necessary to display vivid colors on LCDs. Manufacturers have accordingly commercialized quantum dots, which are light-emitting inorganic materials, to attain that color purity. However, with quantum dots, there is concern about the presence of toxic elements such as cadmium (Cd), and when Cd is replaced by other elements, color purity and efficiency are decreased.
This situation prompted Toray to explore the degradation mechanism for existing organic phosphors, which offer high color purity and efficiency. It drew on its findings to determine a chemical structure and electronic state needed for the molecular design to inhibit degradation. The company thereby developed an organic phosphor that combines high color purity and a fluorescence quantum yield comparable to that of cadmium-based quantum dots while delivering high stability and a resistance to degradation even in the atmosphere. The technology from this breakthrough should contribute to deploying organic phosphors in applications where long-term reliability is essential.
Toray created color conversion sheets using the organic phosphors that it developed, adopting them for LCDs combining wide color gamuts, high efficiency, and nontoxicity. The sheets offer excellent luminous efficiency and can reduce energy losses. They could therefore contribute to developing eco-friendly, energy-saving displays in coming years.
Toray will keep helping to resolve environmental issues by developing advanced materials in keeping with efforts to materialize its corporate philosophy of contributing to society by creating new value through innovative ideas, technologies, and products.
Yasunori Ichihashi, a research associate at Toray's Electronic & Imaging Materials Research Laboratories, and Hirotoshi Sakaino, a senior research engineer at that facility, and the award-winning organic phosphor solution.
Link to Japanese-language article on award-winning technology in Chemistry & Chemical Industry magazine of the Chemical Society of Japan:
https://www.chemistry.or.jp/journal/ci23p164.pdf
Reference
Lumicica
™ organic color conversion sheet for LCDs
https://www.electronics.toray/products/lumirica.html
