Red-emission over a wide range of wavelengths at various temperatures from tetragonal BaCN2:Eu2+
| Autor: | Shinichi Kikkawa, Akira Hosono, Hisanori Yamane, Mikio Higuchi, Yuuki Kitagawa, Jumpei Ueda, Setsuhisa Tanabe, Sayaka Nishitani, Yuji Masubuchi |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
Analytical chemistry Infrared spectroscopy 02 engineering and technology General Chemistry Crystal structure 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Square antiprism Tetragonal crystal system Crystal field theory Excited state Materials Chemistry Quantum efficiency 0210 nano-technology Single crystal |
| Zdroj: | Journal of Materials Chemistry C. 6:6370-6377 |
| ISSN: | 2050-7534 2050-7526 |
| DOI: | 10.1039/c8tc01289j |
| Popis: | A new polymorph of BaCN2 was obtained via a simple nitridation reaction of BaCO3 under an NH3 flow at 900 °C. The product was analyzed via single crystal X-ray diffraction and infrared spectroscopy, and it was found to have a tetragonal I4/mcm crystal structure (space group no. 140) with a = 0.60249(4) nm and c = 0.71924(5) nm. In this structure, each Ba2+ cation is situated in the square antiprism of N atoms of NCN2− anionic groups. Eu2+ doped BaCN2 can be excited by irradiation of blue and green light (from 400 to 550 nm), and it generates an intense red emission peak at 660 nm with a quantum efficiency of 42% in response to 465 nm excitation at room temperature. The peak emission wavelength varies over an extremely wide range of temperature, from 640 nm at 500 K to 680 nm at 80 K, and this red-shift with decreasing temperature is attributed to a unit cell shrinkage that results in significant crystal field splitting of the 5d energy levels of the Eu2+ ions. |
| Databáze: | OpenAIRE |
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