SENSOR Laboratory, Dept. of Information Engineering (DII), Università degli Studi di Brescia, Via Valotti 7, 25123, Italy.
SENSOR Laboratory, Dept. of Information Engineering (DII), Università degli Studi di Brescia, Via Valotti 7, 25123, Italy.
Anal Chim Acta. 2018 Dec 18;1039:1-23. doi: 10.1016/j.aca.2018.09.020. Epub 2018 Sep 17.
This review focuses on the synthesis and chemical sensing characterization of metal oxide heterostructures reported since 2012. Heterostructures exhibit strong interactions between closely packed interfaces, showing superior performances compared to single structures. Surface effects appear thanks to the magnification of nanostructures' surface leading to an enhancement of surface related properties (the base of chemical sensors working mechanism). The combination of different metal oxides to form heterostructures further improves the selectivity and/or other important sensing parameters. A very large number of different morphologies and structures have been proposed, each one exhibiting peculiar sensing properties towards specific chemical compounds. Among the different preparation methodologies, a significant number has been performed by means of hydrothermal method. However, the combination of various fabrication methods seems a very efficient strategy to obtain metal oxide-based heterostructures with different morphologies and dimensions such as core-shell nanostructures, one-dimensional heterostructures, two-dimensional layered heterojunctions, and three-dimensional hierarchical heterostructures. Despite all extraordinary advances in both material science and nanotechnology and the results achieved with heterostructured chemical sensors, there are few points that still deserve further studies and investigations, such as possible diffusion across the junctions, reproducibility of the fabrication process, synergistic or catalytic effects among the materials forming the heterostructures and influence/stability of the contacts. Moreover, perfect control over their growth is mandatory for their application in commercial devices. Only a careful understanding of the growth and the interface properties could fill the existing gap between laboratory studies and real-world exploitation of these heterostructures.
这篇综述重点关注了自 2012 年以来报道的金属氧化物异质结构的合成和化学传感特性。异质结构在紧密堆积的界面之间表现出强烈的相互作用，与单一结构相比具有优异的性能。表面效应是由于纳米结构表面的放大导致表面相关性质增强而出现的（这是化学传感器工作机制的基础）。不同金属氧化物的组合形成异质结构进一步提高了选择性和/或其他重要的传感参数。已经提出了非常多的不同形态和结构，每种形态都对特定的化学化合物表现出独特的传感特性。在不同的制备方法中，水热法得到了广泛的应用。然而，各种制造方法的结合似乎是获得具有不同形态和尺寸的基于金属氧化物的异质结构的非常有效的策略，例如核壳纳米结构、一维异质结构、二维层状异质结和三维分级异质结构。尽管在材料科学和纳米技术方面取得了许多非凡的进展，并且在异质结构化学传感器方面取得了成果，但仍有一些方面值得进一步研究和调查，例如可能在结处扩散、制造过程的可重复性、形成异质结构的材料之间的协同或催化作用以及接触的影响/稳定性。此外，对其生长的完美控制对于它们在商业设备中的应用是强制性的。只有仔细了解生长和界面特性，才能填补这些异质结构实验室研究和实际应用之间的现有差距。
