Key Laboratory of Advanced Ceramics and Machining Technology, Tianjin University, Ministry of Education, School of Materials Science and Engineering, Tianjin 300072, PR China.
Nanoscale. 2012 Mar 7;4(5):1652-7. doi: 10.1039/c2nr11590e. Epub 2012 Feb 2.
Transparent luminescent bulk nanocomposites of polysiloxane (PSO) embedded with semiconductor nanocrystals (NCs) have been fabricated by the direct dispersion of CdS NCs in alkyl-(poly)siloxane (APS) followed by co-polymerization. The non-polar characteristics of the APS precursor are compatible with the CdS NC surface (oleylamine), which allows the direct dispersion of the CdS NCs without the need of any surfactant exchange. Chemical crosslinking of the NC-APS dispersion via hydrosilylation between Si-H and the vinyl group in APS immobilizes the CdS NCs in the polysiloxane network. Net-shaped three-dimensional bulk transparent polysiloxane/CdS NC composites were obtained by liquid casting of the NC-precursor dispersion and chemical crosslinking. The PSO/CdS NC composites show visible luminescence under ultraviolet excitation and the luminescent color is tunable from blue to red by controlling the NC concentration in the composite. Photoluminescence spectral analyses reveal the origin of the luminescence as being from the defect emission of the CdS NCs (550-900 nm) and an emission from the PSO matrix (380-550 nm). The luminescent spectra covered a wide range from the ultraviolet to the near-infrared region. The luminescence of the PSO/CdS NC nanocomposites was stable without any apparent degradation after exposure to air for a long time. This simple direct dispersion process is feasible for the fabrication of luminescent nanocomposites with useful optical properties for potential applications in optics and photoelectron devices.
透明发光块状纳米复合材料的聚硅氧烷（PSO）嵌入半导体纳米晶体（NCs）已通过直接分散的硫化镉 NCs 的烷基（聚）硅氧烷（APS），然后共聚合。非极性的特点的 APS 前体是与硫化镉 NCs 的表面（油胺），这允许直接分散的硫化镉 NCs 没有任何表面活性剂的交换。化学交联的 NC-APS 分散通过 hydrosilylation 之间的 Si-H 和乙烯基在 APS 固定的硫化镉 NCs 在聚硅氧烷网络。网状三维透明聚硅氧烷/CdS NC 复合材料是由液体铸造的 NC-前体分散体和化学交联。PSO/CdS NC 复合材料表现出可见光发射下的紫外激发和发光颜色可调从蓝色到红色的 NC 浓度的控制在复合材料中。光致发光光谱分析揭示了发光的起源是从缺陷发射的硫化镉 NCs（550-900nm）和一个发射从聚硅氧烷基质（380-550nm）。发光光谱涵盖了从紫外到近红外区域的宽范围。发光的 PSO/CdS NC 纳米复合材料是稳定的没有任何明显的退化后暴露在空气中很长一段时间。这种简单的直接分散过程是可行的发光纳米复合材料具有有用的光学性能在光学和光电设备的潜在应用。
