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Title:	Integrated Strategy toward Self-Powering and Selectivity Tuning of Semiconductor Gas Sensors
Author:	Gad, Alaaeldin; Hoffmann, Martin W. G.; Casals Guillén, Olga; Mayrhofer, Leonhard; Fábrega, Cristian; Caccamo, Lorenzo; Hernández Ramírez, Francisco; Mohajerani, Matin S.; Moseler, Michael; Shen, Hao; Waag, Andreas; Prades García, Juan Daniel
Other authors:	Universitat de Barcelona
Abstract:	Inorganic conductometric gas sensors struggle to overcome limitations in high power consumption and poor selectivi-ty. Herein, recent advances in developing self-powered gas sensors with tunable selectivity are introduced. Alternative general approaches for powering gas sensors were realized via proper integration of complementary functionalities (namely; powering and sensing) in a singular heterostructure. These solar light driven gas sensors operating at room temperature without applying any additional external powering sources are comparatively discussed. The TYPE-1 gas sensor based on integration of pure inorganic interfaces (e.g. CdS/n-ZnO/p-Si) is capable of delivering a self-sustained sensing response, while it shows a non-selective interaction towards oxidizing and reducing gases. The structural and the optical merits of TYPE-1 sensor are investigated giving more insights into the role of light activation on the modu-lation of the self-powered sensing response. In the TYPE-2 sensor, the selectivity of inorganic materials is tailored through surface functionalization with self-assembled organic monolayers (SAMs). Such hybrid interfaces (e.g. SAMs/ZnO/p-Si) have specific surface interactions with target gases compared to the non-specific oxidation-reduction interactions governing the sensing mechanism of simple inorganic sensors. The theoretical modeling using density functional theory (DFT) has been used to simulate the sensing behavior of inorganic/organic/gas interfaces, revealing that the alignment of organic/gas frontier molecular orbitals with respect to the inorganic Fermi level is the key factor for tuning selectivity. These platforms open new avenues for developing advanced energy-neutral gas sensing devices and concepts.
Subject(s):	-Detectors de gasos -Nanoestructures -Semiconductors -Gas detectors -Nanostructures -Semiconductors
Rights:	(c) American Chemical Society , 2016
Document type:	Article Article - Accepted version
Published by:	American Chemical Society
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