Eu<sub>0.56</sub>Ta<sub>2</sub>O<sub>7</sub>:  A New Nanosheet Phosphor with the High Intrananosheet Site Photoactivator Concentration Tadashi C. Ozawa Katsutoshi Fukuda Kosho Akatsuka Yasuo Ebina Takayoshi Sasaki Keiji Kurashima Kosuke Kosuda 10.1021/jp711699c.s002 https://acs.figshare.com/articles/journal_contribution/Eu_sub_0_56_sub_Ta_sub_2_sub_O_sub_7_sub_A_New_Nanosheet_Phosphor_with_the_High_Intrananosheet_Site_Photoactivator_Concentration/2958631 High photoactivator concentration nanosheets Eu<sub>0.56</sub>Ta<sub>2</sub>O<sub>7</sub> have been prepared by the soft chemical exfoliation reaction of the layered perovskite Li<sub>2</sub><sub>-</sub><i><sub>x</sub></i>H<i><sub>x</sub></i>Eu<sub>0.56</sub>Ta<sub>2</sub>O<sub>7</sub> with a tetrabutylammonium hydroxide aqueous solution. In-plane X-ray diffraction and TEM and AFM observation results indicate that the Eu<sub>0.56</sub>Ta<sub>2</sub>O<sub>7</sub> nanosheet is crystalline and retains the layered perovskite structural feature of the bulk precursors. The most intense emission is observed from the <sup>5</sup>D<sub>0</sub> → <sup>7</sup>F<sub>2</sub> transition of Eu<sup>3+</sup>. The intensity of this emission by the host excitation exceeds 18 times that by the direct Eu<sup>3+</sup> excitation. 2008-02-07 00:00:00 Eu 0.56Ta emission host excitation perovskite High Intrananosheet Site Photoactivator ConcentrationHigh photoactivator concentration nanosheets Eu 0.56Ta Eu 0.56Ta nanosheet bulk precursors chemical exfoliation reaction AFM observation results 18 times TEM New Nanosheet Phosphor tetrabutylammonium hydroxide