Giant Chemo-Resistance of SnO disk-like structures

Sensors and Actuators B-Chemical Volume: 186 Pages: 103-108 Published: 2013

(a) Low-Mag FEG-SEM image of disk-like structures present in the collected material after sedimentation process. High magnification images of isolated disks are presented in (b) and (c) showing octagon-like and circular shape, respectively.

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Writers: P.H. Suman; A.A. Felix; H.L. Tuller; J.A. Varela; M.O. Orlandi

Keywords: SnO; Giant chemo-resistance; Gas sensor

Abstract: Single crystalline SnO micro-disks, synthesized by a carbothermal reduction process, exhibited a nearly 1000-fold increase in resistance upon exposure to 100 ppm of NO2 without addition of catalysts or dopants nor the existence of nano-sized dimensions. Moreover, the SnO displayed a greater than 100-fold selectivity to NO2 over potential interferents including CO, H2 and CH4. The high sensor signal and exceptional selectivity for this novel sensor material are attributed to the existence of a high density of active lone pair electrons on the exposed (0 0 1) planes of the single crystalline SnO disks. This, thereby, identifies new means, not utilizing nano-dimensions, to achieve high gas sensitivity.

Robson Lima
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Atua no Centro de Desenvolvimento de Materiais Funcionais.