Fioravanti Ambra, Marani Pietro, Morandi Sara, Lettieri Stefano, Mazzocchi Mauro, Sacerdoti Michele, Carotta Maria Cristina
Istituto di Scienze e Tecnologie per l'Energia e la Mobilità Sostenibili (CNR-STEMS), Via Canal Bianco 28, 44124 Ferrara, Italy.
Dipartimento di Chimica, Università di Torino, Via P. Giuria 7, 10125 Torino, Italy.
Sensors (Basel). 2021 Feb 13;21(4):1331. doi: 10.3390/s21041331.
Zinc oxide (ZnO) is one of the main functional materials used to realize chemiresistive gas sensors. In addition, ZnO can be grown through many different methods obtaining the widest family of unique morphologies. However, the relationship between the ZnO morphologies and their gas sensing properties needs more detailed investigations, also with the aim to improve the sensor performances. In this work, seven nanoforms (such as leaves, bisphenoids, flowers, needles, etc.) were prepared through simple wet chemical synthesis. Morphological and structural characterizations were performed to figure out their growth mechanisms. Then, the obtained powders were deposited through screen-printing technique to realize thick film gas sensors. The gas sensing behavior was tested toward some traditional target gases and some volatile organic compounds (acetone, acetaldehyde, etc.) and compared with ZnO morphologies. Results showed a direct correlation between the sensors responses and the powders features (morphology and size), which depend on the specific synthesis process. The sensors can be divided in two behavioral classes, following the two main morphology kinds: aggregates of nanocrystals (leaves and bisphenoids), exhibiting best performances versus all tested gases and monocrystal based (stars, needle, long needles, flowers, and prisms).
氧化锌（ZnO）是用于实现化学电阻式气体传感器的主要功能材料之一。此外，ZnO可以通过许多不同的方法生长，从而获得种类最为丰富的独特形态。然而，ZnO形态与其气敏特性之间的关系需要更详细的研究，目的也是为了提高传感器性能。在这项工作中，通过简单的湿化学合成制备了七种纳米形态（如叶片、双晶、花朵、针状等）。进行了形态和结构表征以弄清楚它们的生长机制。然后，通过丝网印刷技术沉积所得粉末以实现厚膜气体传感器。测试了对一些传统目标气体和一些挥发性有机化合物（丙酮、乙醛等）的气敏行为，并与ZnO形态进行了比较。结果表明传感器响应与粉末特性（形态和尺寸）之间存在直接关联，而粉末特性取决于具体的合成过程。根据两种主要的形态种类，传感器可分为两类行为：纳米晶体聚集体（叶片和双晶），对所有测试气体表现出最佳性能；以及基于单晶的（星形、针状、长针状、花朵状和棱柱形）。
