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• Coppedè, N
• Villani, M
• Mosca, R
• Iannotta, S
• Zappettini, A
• Calestani, D
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• Coppedè, N
• Villani, M
• Mosca, R
• Iannotta, S
• Zappettini, A
• Calestani, D
• [+] on PubMed
• Coppedè, N
• Villani, M
• Mosca, R
• Iannotta, S
• Zappettini, A
• Calestani, D

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Sensors 2013, 13(3), 3445-3453; doi:10.3390/s130303445

Article

Low Temperature Sensing Properties of a Nano Hybrid Material Based on ZnO Nanotetrapods and Titanyl Phthalocyanine

Nicola Coppedè, Marco Villani, Roberto Mosca, Salvatore Iannotta, Andrea Zappettini and Davide Calestani*

Istituto dei Materiali per l' Elettronica ed il Magnetismo (IMEM), Consiglio Nazionale delle Ricerche (CNR), Parco Area delle Scienze 37/A 43124 Parma, Italy

* Author to whom correspondence should be addressed.

Received: 22 January 2013; in revised form: 7 March 2013 / Accepted: 8 March 2013 / Published: 13 March 2013

(This article belongs to the Special Issue Organics and Metal Oxide Hybrid Sensors)

Download PDF Full-Text [601 KB, uploaded 13 March 2013 11:16 CET]

Abstract: ZnO nanotetrapods have recently been exploited for the realization of high-sensitivity gas sensors, but they are affected by the typical drawbacks of metal-oxides, i.e., poor selectivity and a relatively high working temperature. On the other hand, it has been also demonstrated that the combined use of nanostructured metal oxides and organic molecules can improve the gas sensing performance sensitivity or selectivity, even at lower temperatures. A gas sensor device, based on films of interconnected ZnO nanotetrapods properly functionalized by titanyl phthalocyanine (TiOPc), has been realized in order to combine the high surface to volume ratio and structural stability of the crystalline ZnO nanostructures with the enhanced sensitivity of the semiconducting TiOPc molecule, especially at low temperature. The electronic properties of the resulting nanohybrid material are different from those of each single component. The response of the hybrid nanostructure towards different gases has been compared with that of ZnO nanotetrapod without functionalization in order to highlight the peculiar properties of the hybrid interaction(s). The dynamic response in time has been studied for different gases and temperatures; in particular, an increase in the response to NO₂ has been observed, even at room temperature. The formation of localized p-n heterojunctions and the possibility of exchanging charge carriers at the hybrid interface is shown to be crucial for the sensing mechanism.

Keywords: gas sensor; ZnO nanostructures; phthalocyanine; NO₂; room temperature

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