Department of Solid State Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India.
Nanoscale. 2011 May;3(5):2336-41. doi: 10.1039/c1nr10064e. Epub 2011 Apr 11.
Core-shell TiO(2)@ZnO nanorods (NRs) have been fabricated by a simple two step method: growth of ZnO NRs' array by an aqueous chemical technique and then coating of the NRs with a solution of titanium isopropoxide [Ti(OC(3)H(7))(4)] followed by a heating step to form the shell. The core-shell nanocomposites are composed of single-crystalline ZnO NRs, coated with a thin TiO(2) shell layer obtained by varying the number of coatings (one, three and five times). The ultraviolet (UV) emission intensity of the nanocomposite is largely quenched due to an efficient electron-hole separation reducing the band-to-band recombinations. The UV photoconductivity of the core-shell structure with three times TiO(2) coating has been largely enhanced due to photoelectron transfer between the core and the shell. The UV photosensitivity of the nanocomposite becomes four times larger while the photocurrent decay during steady UV illumination has been decreased almost by 7 times compared to the as-grown ZnO NRs indicating high efficiency of these core-shell structures as UV sensors.
核壳结构 TiO(2)@ZnO 纳米棒（NRs）通过一种简单的两步法制备：通过水相化学技术生长 ZnO NRs 阵列，然后用钛异丙醇盐[Ti(OC(3)H(7))(4)]溶液涂覆 NRs，随后进行加热步骤以形成壳层。核壳纳米复合材料由单晶 ZnO NRs 组成，表面涂覆有一层通过改变涂层数量（一次、三次和五次）获得的薄 TiO(2)壳层。由于有效的电子-空穴分离减少了带-带复合，纳米复合材料的紫外（UV）发射强度大大猝灭。具有三次 TiO(2)涂层的核壳结构的 UV 光电导率由于核和壳之间的光电子转移而大大增强。与原始生长的 ZnO NRs 相比，纳米复合材料的 UV 灵敏度增加了四倍，而在稳定的 UV 照射下的光电流衰减几乎降低了 7 倍，表明这些核壳结构作为 UV 传感器的效率很高。
