Monodisperse and hollow structured Y2O3:Ln3+ (Ln = Eu, Dy, Er, Tm) nanospheres: A facile synthesis and multicolor-tunable luminescence properties

A novel, fast and simple method was developed to synthesize the undoped and lanthanide-doped yttrium oxide hollow nanospheres (Y2O3⋅HNSs) with multicolored downconversion emission under mild conditions by employing poly (acrylic acid sodium salt) microspheres (PAAS MSs) as active templates followed by a subsequent calcination process. The structure, morphology, formation process, and fluorescent properties are well investigated using various techniques. The results show that the samples can be well indexed to the pure cubic phase of Y2O3. The possible formation mechanism of the PAAS MSs, PAA-Y precursor, and Y2O3 HNSs are proposed and discussed in detail. Upon ultraviolet excitation, the obtained Y2O3:Ln3+ (Ln = Eu, Dy, Er, Tm) HNSs exhibit strong red, yellow-green, blue, yellow emission, respectively. Moreover, a novel single-phased and near-UV-pumped white-light-emitting phosphor Y2O3:Tm3+, Dy3+ was also successfully fabricated through optimizing the molar ratio among Tm3+ and Dy3+ in the Y2O3 host. This material may find potential applications in field-emission display devices and white ultraviolet light-emitting diodes (UV LEDs). Furthermore, this synthesis route may be of great significance in the preparation of other hollow spherical materials.