Karmaoui Mohamed, Jorge Ana Belen, McMillan Paul F, Aliev Abil E, Pullar Robert C, Labrincha João António, Tobaldi David Maria
Department of Materials and Ceramic Engineering/CICECO-Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
Département de Génie Chimique, Faculté de Chimie, Université des Sciences et de la technologie Mohamed-Boudiaf El Mnaouar, BP 1505, Bir El Djir, 31000 Oran, Algeria.
ACS Omega. 2018 Oct 15;3(10):13227-13238. doi: 10.1021/acsomega.8b02122. eCollection 2018 Oct 31.
Because of its electrically conducting properties combined with excellent thermal stability and transparency throughout the visible spectrum, tin oxide (SnO) is extremely attractive as a transparent conducting material for applications in low-emission window coatings and solar cells, as well as in lithium-ion batteries and gas sensors. It is also an important catalyst and catalyst support for oxidation reactions. Here, we describe a novel nonaqueous sol-gel synthesis approach to produce tin oxide nanoparticles (NPs) with a low NP size dispersion. The success of this method lies in the nonhydrolytic pathway that involves the reaction between tin chloride and an oxygen donor, 1-hexanol, without the need for a surfactant or subsequent thermal treatment. This one-pot procedure is carried out at relatively low temperatures in the 160-260 °C range, compatible with coating processes on flexible plastic supports. The NP size distribution, shape, and dislocation density were studied by powder X-ray powder diffraction analyzed using the method of whole powder pattern modeling, as well as high-resolution transmission electron microscopy. The SnO NPs were determined to have particle sizes between 3.4 and 7.7 nm. The reaction products were characterized using liquid-state C and H nuclear magnetic resonance (NMR) that confirmed the formation of dihexyl ether and 1-chlorohexane. The NPs were studied by a combination of C, H, and Sn solid-state NMR as well as Fourier transform infrared (FTIR) and Raman spectroscopy. The C SSNMR, FTIR, and Raman data showed the presence of organic species derived from the 1-hexanol reactant remaining within the samples. The optical absorption, studied using UV-visible spectroscopy, indicated that the band gap ( ) shifted systematically to lower energy with decreasing NP sizes. This unusual result could be due to mechanical strains present within the smallest NPs perhaps associated with the organic ligands decorating the NP surface. As the size increased, we observed a correlation with an increased density of screw dislocations present within the NPs that could indicate relaxation of the stress. We suggest that this could provide a useful method for band gap control within SnO NPs in the absence of chemical dopants.
由于氧化锡（SnO）具有导电性能，同时在整个可见光谱范围内具有出色的热稳定性和透明度，因此作为一种透明导电材料极具吸引力，可用于低发射窗涂层、太阳能电池以及锂离子电池和气体传感器。它还是氧化反应的重要催化剂和催化剂载体。在此，我们描述了一种新颖的非水溶胶 - 凝胶合成方法，用于制备具有低纳米颗粒尺寸分散性的氧化锡纳米颗粒（NPs）。该方法的成功之处在于非水解途径，该途径涉及氯化锡与氧供体1 - 己醇之间的反应，无需表面活性剂或后续热处理。这个一锅法过程在160 - 260°C的相对低温下进行，与柔性塑料载体上的涂层工艺兼容。通过使用全粉末图案建模方法分析的粉末X射线粉末衍射以及高分辨率透射电子显微镜研究了纳米颗粒的尺寸分布、形状和位错密度。确定SnO纳米颗粒的粒径在3.4至7.7纳米之间。使用液态碳和氢核磁共振（NMR）对反应产物进行了表征，证实了二己基醚和1 - 氯己烷的形成。通过碳、氢和锡固态NMR以及傅里叶变换红外（FTIR）和拉曼光谱对纳米颗粒进行了研究。碳固态NMR、FTIR和拉曼数据表明样品中存在源自1 - 己醇反应物的有机物种。使用紫外 - 可见光谱研究的光吸收表明，随着纳米颗粒尺寸的减小，带隙（ ）系统地向更低能量移动。这个不寻常的结果可能是由于最小的纳米颗粒中存在机械应变，这可能与装饰纳米颗粒表面的有机配体有关。随着尺寸的增加，我们观察到与纳米颗粒中存在的螺旋位错密度增加相关，这可能表明应力的松弛。我们认为，在没有化学掺杂剂的情况下，这可以为控制SnO纳米颗粒内的带隙提供一种有用的方法。
