Multifunctional Materials: A Case Study of the Effects of Metal Doping on ZnO Tetrapods with Bismuth and Tin Oxides

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• 作者：Vasile Postica ; Jorit Grö ; ttrup ; Rainer Adelung ; Oleg Lupan ; Abhishek Kumar Mishra ; Nora H. de Leeuw ; Nicolai Ababii ; José ; F. C. Carreira ; Joana Rodrigues ; Nebiha Ben Sedrine ; Maria Rosá ; rio Correia ; Teresa Monteiro ; Victor Sontea and Yogendra Kumar Mishra
• 刊名：Advanced Functional Materials
• 出版年：2017
• 出版时间：February 10, 2017
• 年：2017
• 卷：27
• 期：6
• 全文大小：3427K
• ISSN：1616-3028

文摘

Hybrid metal oxide nano- and microstructures exhibit novel properties, which make them promising candidates for a wide range of applications, including gas sensing. In this work, the characteristics of the hybrid ZnO-Bi₂O₃ and ZnO-Zn₂SnO₄ tetrapod (T) networks are investigated in detail. The gas sensing studies reveal improved performance of the hybrid networks compared to pure ZnO-T networks. For the ZnO-T-Bi₂O₃ networks, an enhancement in H₂ gas response is obtained, although the observed p-type sensing behavior is attributed to the formed junctions between the arms of ZnO-T covered with Bi₂O₃ and the modulation of the regions where holes accumulate under exposure to H₂ gas. In ZnO-T-Zn₂SnO₄ networks, a change in selectivity to CO gas with high response is noted. The devices based on individual ZnO-T-Bi₂O₃ and ZnO-T-Zn₂SnO₄ structures showed an enhanced H₂ gas response, which is explained on the basis of interactions (electronic sensitization) between the ZnO-T arm and Bi₂O₃ shell layer and single Schottky contact structure, respectively. Density functional theory-based calculations provide mechanistic insights into the interaction of H₂ and CO gas molecules with Bi- and Sn-doped ZnO(0001) surfaces, revealing changes in the Fermi energies, as well as charge transfer between the molecules and surface species, which facilitate gas sensing.