硫化铋准纳米带阵列的可控合成及光学性质

Controlled Synthesis of Quasi-Aligned Bi_2S_3 Nanobelt Arrays and Their Photoluminescence Property

以五水硝酸铋和硫脲为原料,采用籽晶技术和水热相结合的方法,在涂籽晶层的硅片上制备了大面积Bi2S3准纳米带阵列。利用X射线衍射、场发射扫描电子显微镜、透射电子显微镜、高分辨透射电子显微镜和电子衍射等对产物的结构和形貌进行表征。结果表明,合成产物为纯正交相的纯Bi2S3,纳米带阵列中的纳米带宽约为130 nm,长约2μm,并且沿[130]方向优先生长。使用涂有Bi2S3纳米籽晶的衬底是生长大规模准纳米带阵列的必要条件,衬底在高压釜中放置高度影响产物的形貌。Bi2S3准纳米带阵列的形成机理与自组装生长和Bi2S3的各向异性生长相关。产物的荧光光谱为从650nm到800nm的红光区域宽发光带,是由Bi2S3准纳米带阵列结构中的复杂缺陷导致的。

Single-crystalline quasi-aligned Bi2S3 nanobelt arrays on a silicon substrate were fabricated with bismuth nitrate pentahydrate and thiourea as raw materials by a simple seed-assistant hydrothermal method. The phase structure and morphology of the as-prepared products were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy and selected area electron diffraction, respectively. The results show that the products prepared are the pure quadrature phase Bi2S3 nanobelt arrays. The nanobelts with the sizes of 130 nm in width and 2μm in length grow along the [130] direction. The preformed Bi2S3 seed-layer on the substrate is a necessary condition for the forma-tion of the quasi-aligned Bi2S3 nanobelt arrays. The height of the substrate placed in the autoclave affected the morphology of Bi2S3 nanobelts. A possible growth mechanism involving self-assembly and the anisotropic growth process was proposed for the formation of Bi2S3 nanobelts arrays. The room-temperature photoluminescence （PL） spectra indicated that there was an intensive and broad PL band in the wavelength range from 650 nm to 800 nm, which was ascribed to the complex defect species of the product.