Sensitivity enhancement for NO2 gas sensor based on Alq3:TiO2

In this study, Tris (8-hydroxyquinoline) aluminum (III) (Alq3) mixed with Titanium oxide (TiO2) at the ratios (0, 0.04, 0.06, and 0.08)Vol.%, were deposited on indium tin oxide (ITO) as substrate by spin coated method, for the manufacture of gas sensor device. All films were annealed at 423° K. X-ra...

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Bibliographic Details
Published in:AIP Conference Proceedings 2021-11, Vol.2372 (1)
Main Authors: Mohammed, Abubaker S., Fahad, Othman Abed
Format: Article
Language:English
Subjects:
Aluminum
Atomic force microscopes
Atomic force microscopy
Energy
Energy gap
Gas sensors
Grain size
Hydroxyquinoline
Indium tin oxides
Nitrogen dioxide
Optical properties
Sensitivity enhancement
Sensors
Substrates
Titanium dioxide
Titanium oxides
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Summary:In this study, Tris (8-hydroxyquinoline) aluminum (III) (Alq3) mixed with Titanium oxide (TiO2) at the ratios (0, 0.04, 0.06, and 0.08)Vol.%, were deposited on indium tin oxide (ITO) as substrate by spin coated method, for the manufacture of gas sensor device. All films were annealed at 423° K. X-ray diffraction (XRD), atomic force microscope (AFM) and optical properties (Uv-visible) of all films have been studied. X-ray of Alq3 pure and doped at 0.04 TiO2 indicated that the films have amorphous structure, while the films prepared at the ratios 0.06 and 0.08 Vol. % of TiO2, have a polycrystalline structure. The results reveal that the grain size of Alq3 pure is approximately 96.13 nm and decrease to 57.59 nm with increase TiO2 content. Optical energy gap shows of the amorphous Alq3 and 0.04 of TiO2 have two energy gap, the analysis of the data showed these two films have an indirect allowed transition energy gap (Egind of 2.7and 2.75 eV) respectively, addition other probability of direct allowed transition out with energy gaps (Egd of 3.56 and 3.79 eV) respectively. The increase of titanium ratios at 0.06 and 0.08Vol.%, lead to appeared one direct energy gap (Egd of 3.56 and 3.79 eV) respectively. NO2 gas sensor was fabricated using Au/Alq3:TiO2/ITO/glass at different ratios of TiO2. The sensitivity improved significantly with increasing TiO2 ratio. More effect of TiO2 was appeared when added to the Alq3, this is evidenced by the effect of shifting energy gap behavior and the roughness on the sensor properties.
ISSN:0094-243X
1551-7616
DOI:10.1063/5.0065972