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Langmuir. 2012 Feb 28;28(8):3962-71. doi: 10.1021/la204469f. Epub 2012 Feb 16.
Europium-doped lanthanide oxide RE(2)O(3):Eu(3+) (RE = Y or Gd) luminescent beads, with a spherical shape and a diameter of 150 ± 15 nm, have been modified by reaction with 3-aminopropyltriethoxysilane (APTES), in order to introduce reactive amine groups at their surfaces. The direct silanation has resulted in the formation of a nanometric layer at the surface of the beads, with an optimum grafting rate of 0.055 ± 0.005 mol APTES/mol RE(2)O(3). Fourier transform infrared (FTIR) and X-ray photoelectron (XPS) spectroscopies confirmed the condensation of an organosilane layer, made of cross-linked -O-Si-O-Si- and of groups -O-Si-R (with R = (CH(2))(3)NH(2) or O-Et). Titration of the accessible amine groups has been performed by simultaneously measuring the luminescence of grafted fluorescein isothiocyanate and that of core particles: there are about 2.3 × 10(4) (2.8 × 10(4)) -NH(2) per Y(2)O(3):Eu(3+) (Gd(2)O(3):Eu(3+)) bead. The isoelectronic point was shifted by one pH unit after APTES modification. The surface modification by APTES at least preserved (for Gd(2)O(3):Eu(3+)) or improved (for Y(2)O(3):Eu(3+)) the red emission of the beads.
铕掺杂的镧系氧化物 RE(2)O(3):Eu(3+)（RE = Y 或 Gd）发光珠，具有球形，直径为 150 ± 15nm，通过与 3-氨丙基三乙氧基硅烷（APTES）反应进行了修饰，以便在其表面引入反应性胺基团。直接硅烷化导致在珠的表面形成纳米级层，接枝率最佳为 0.055 ± 0.005mol APTES/mol RE(2)O(3)。傅里叶变换红外（FTIR）和 X 射线光电子能谱（XPS）证实了由交联-O-Si-O-Si-和-O-Si-R 基团（其中 R = (CH(2))(3)NH(2)或 O-Et）组成的有机硅烷层的缩合。通过同时测量接枝的荧光素异硫氰酸酯和核颗粒的荧光，可以对可及的胺基团进行滴定：每个 Y(2)O(3):Eu(3+)（Gd(2)O(3):Eu(3+))珠上约有 2.3 × 10(4)（2.8 × 10(4)) -NH(2)。APTES 修饰后等电点移动了一个 pH 单位。APTES 的表面修饰至少保留了（对于 Gd(2)O(3):Eu(3+)）或改善了（对于 Y(2)O(3):Eu(3+)）珠的红色发射。
