Xu Zhenhe, Zhao Qian, Ren Baoyi, You Lixin, Sun Yaguang
J Nanosci Nanotechnol. 2014 Aug;14(8):5781-9. doi: 10.1166/jnn.2014.8741.
Multicolor and monodisperse Y2O3:Ln(3+) (Ln(3+) = Eu(3+), Tb(3+), Dy(3+), Sm(3+), Er(3+), Ho(3+), Tm(3+), Yb(3+)/Er(3+), Yb(3+)/Ho(3+)) microspheres were prepared through a facile urea-assisted homogeneous precipitation method followed by a subsequent calcination process. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectrum (EDS), Fourier transformed infrared (FT-IR), thermogravimetric analysis (TGA), photoluminescence (PL) and cathodoluminescence (CL) spectra were employed to characterize the samples. The XRD results reveal that the as-prepared spheres can be well indexed to cubic Y2O3 phase with high purity. The SEM and TEM images show the obtained Y2O3:Ln(3+) samples consist of regular nanospheres with the mean diameter of 350 nm. And the possible formation mechanism is also proposed. Upon ultraviolet and low-voltage electron beams excitation, Y2O3:Ln(3+) (Ln(3+) = Eu(3+), Tb(3+), Dy(3+), Sm(3+), Er(3+), Ho(3+), Tm(3+)) samples exhibit respective bright red (Eu(3+), (5)D0 --> (7)F2), green (Tb(3+), (5)D4 --> (7)F5), blue (Dy(3+), (4)F9/2 --> (6)H13/2), yellow (Sm(3+), (4)G5/2 --> (6)H7/2), green (Er(3+), (4)S3/2 --> (4)I15/2), green (Ho(3+), (5)S2 --> (5)I8), blue (Tm(3+), (1)D2 --> (3)F4) down-conversion (DC) emissions. Under 980 nm NIR irradiation, Y2O3:Ln(3+) (Ln(3+) = Yb(3+)/Er(3+), Yb(3+)/Tm(3+) and Yb(3+)/Ho(3+)) exhibit characteristic up-conversion (UC) emissions of green (Er(3+), (2)H11/2, (4)S3/2, (2)H11/2 --> (4)I5/2), blue (Tm(3+), (1)G4 --> (3)H6) and green (Ho(3+), (5)F4, (5)S2 --> (5)I8), respectively. These merits of multicolor emissions in the visible region endow this kind of material with potential applications in the field of light display systems, lasers, and optoelectronic devices.
通过简便的尿素辅助均匀沉淀法并随后进行煅烧过程，制备了多色单分散的Y2O3:Ln(3+)（Ln(3+) = Eu(3+)、Tb(3+)、Dy(3+)、Sm(3+)、Er(3+)、Ho(3+)、Tm(3+)、Yb(3+)/Er(3+)、Yb(3+)/Ho(3+)）微球。采用X射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、高分辨率透射电子显微镜（HRTEM）、能量色散X射线光谱（EDS）、傅里叶变换红外（FT-IR）、热重分析（TGA）、光致发光（PL）和阴极发光（CL）光谱对样品进行表征。XRD结果表明，所制备的微球可以很好地索引到高纯度的立方Y2O3相。SEM和TEM图像显示，所获得的Y2O3:Ln(3+)样品由平均直径为350 nm的规则纳米球组成。并且还提出了可能的形成机制。在紫外光和低电压电子束激发下，Y2O3:Ln(3+)（Ln(3+) = Eu(3+)、Tb(3+)、Dy(3+)、Sm(3+)、Er(3+)、Ho(3+)、Tm(3+)）样品分别表现出亮红色（Eu(3+)，(5)D0→(7)F2）、绿色（Tb(3+)，(5)D4→(7)F5）、蓝色（Dy(3+)，(4)F9/2→(6)H13/2）、黄色（Sm(3+)，(4)G5/2→(6)H7/2）、绿色（Er(3+)，(4)S3/2→(4)I15/2）、绿色（Ho(3+)，(5)S2→(5)I8）、蓝色（Tm(3+)，(1)D2→(3)F4）的下转换（DC）发射。在980 nm近红外照射下，Y2O3:Ln(3+)（Ln(3+) = Yb(3+)/Er(3+)、Yb(3+)/Tm(3+)和Yb(3+)/Ho(3+)）分别表现出绿色（Er(3+)，(2)H11/2，(4)S3/2，(2)H11/2→(4)I5/2）、蓝色（Tm(3+)，(1)G4→(3)H6）和绿色（Ho(3+)，(5)F4，(5)S2→(5)I8）的特征上转换（UC）发射。这种材料在可见光区域的多色发射优点使其在光显示系统、激光器和光电器件领域具有潜在应用。
