Au/Bi共掺二氧化硅薄膜的制备及近红外光谱调控

根据X射线光电子能谱分析和选择性光致发光谱测试结果,探讨了Bi离子掺杂非晶二氧化硅薄膜的近红外发光来源。我们认为非晶二氧化硅薄膜中Bi离子的近红外发光来源于低价态Bi~+离子从轨道~3P_1层到~3P_0层的辐射复合跃迁和Bi~0从轨道~2D_(3/2)层到~4S_(3/2)层的辐射复合跃迁。此外,本文利用限制性晶化原理,通过在掺Bi二氧化硅薄膜中引入Au离子,实现了Bi离子相关的近红外发光峰位可调,荧光强度增大了300%。高分辨透射电子显微镜截面图片证实了非晶二氧化硅薄膜厚度约为90 nm以及不同尺寸、数密度Au量子点的形成。变温光致发光谱测试结果表明,部分Au离子可有效降低Bi离子掺杂非晶二氧化硅薄膜中羟基集团等非辐射复合中心密度。Bi离子掺杂非晶二氧化硅薄膜近红外发光来源的探讨以及通过Au量子点调控Bi离子近红外发光性质的讨论将有助于未来掺Bi发光材料的相关研究。

Fabrication and Near-infrared Spectral Modulation of Au/Bi Ions Co-doped Silica Thin Films

Near-infrared luminescence origin of Bi-doped amorphous silica thin film is discussed by the XPS characterizations and selective PL measurements. The nature of the near-infrared emission in amorphous silica thin film is considered as both the transition of Bi⁺ ions from ³P₁ to ³P₀ and the transition of Bi⁰ from ²D_3/2 to ⁴S_3/2. Further, the confined crystallization growth strategy is designed for fabricating uniform-size Au quantum dots embedded in Bi-doped silica thin film. Through controls of the doping amounts of Au ions, the NIR emission of Bi ions in silica thin film can be wavelength-tunable and enhanced by nearly 300% on the optimum Au ions doping amount. The thickness of thin film is 90 nm and the formation of Au quantum dots with different average sizes and number densities have been confirmed by the high-resolution TEM images. Temperature-dependent PL emission spectra suggest parts of Au ions may play a role of eliminating hydroxyl groups, which gives rises to greatly enhanced PL intensity in the near-infrared region. We anticipate that both greatly enhanced and wavelength-tunable NIR luminescence and discussion of luminescence origin would shed light on future research of Bi ions-doped luminescent materials.