Department of Solid State Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
Nanotechnology. 2011 Jul 1;22(26):265501. doi: 10.1088/0957-4484/22/26/265501. Epub 2011 May 17.
ZnO nanowires (NWs) have been decorated with Pd nanoparticles of sizes less than 10 nm (Pd-ZnO NWs) via a chemical solution route. The microstructural characterizations have been done using field emission scanning electron and high-resolution transmission electron microscopes. The effects of attaching Pd nanoparticles to the walls of ZnO NWs have been investigated by studying the ultraviolet (UV) photosensitivity and photoluminescence (PL) properties. The surface-modified NWs show a UV photosensitivity more than double and a response seven times faster compared to the bare NWs. The photocarrier relaxation under the steady UV illumination condition is quite different in Pd-ZnO NWs. The higher and faster photosensitivity has been explained on the basis of photocarrier transfer from the conduction band of ZnO to the Fermi level of Pd and subsequent electron trapping by the adsorbed O(2) molecules on the NWs' surface, which have been presented through a proposed model. The PL spectrum of Pd-ZnO NWs shows that the intensities of the band-edge and defect-related emissions decrease and increase, respectively, due to Pd anchoring, the effect being pronounced as the density of Pd nanoparticles increases.
通过化学溶液途径，在氧化锌纳米线（NWs）上修饰了小于 10nm 的钯纳米颗粒（Pd-ZnO NWs）。使用场发射扫描电子显微镜和高分辨率透射电子显微镜进行了微观结构表征。通过研究紫外（UV）光敏性和光致发光（PL）性质，研究了将钯纳米颗粒附着到 ZnO NWs 壁上的效果。与裸 NWs 相比，表面修饰的 NWs 的 UV 光敏性提高了一倍以上，响应速度快了七倍。在稳定的 UV 照射条件下，光载流子弛豫的情况在 Pd-ZnO NWs 中完全不同。基于光载流子从 ZnO 的导带转移到 Pd 的费米能级以及随后被吸附在 NWs 表面的 O(2)分子捕获的电子，解释了更高和更快的光敏性，通过提出的模型进行了介绍。Pd-ZnO NWs 的 PL 光谱表明，由于 Pd 固定，带边和缺陷相关发射的强度分别减小和增加，当钯纳米颗粒的密度增加时，这种效应更加明显。
