Preparation and characterization of the titanium dioxide thin films used for pH electrode and procaine drug sensor by sol–gel method

Liao, Yi-Hung; Chou, Jung-Chuan

doi:10.1016/j.matchemphys.2008.10.014

Cited by 71 publications

(35 citation statements)

References 25 publications

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“…Larger amount of cracks are also visualized at the surface of 10Ti, probably due to excess TiO 2 in the brookite phase and its low interaction with the vanadium oxide. These observed cracks are similar to the ones for the case of pure TiO 2 obtained by sol-gel method, 25 thus confirming the segregation of TiO 2 at the topmost surface of the films, as suggested by the EDS results. When more TiO 2 is added, as in the case of sample 15Ti, a more uniform surface is achieved.…”

Section: Resultssupporting

confidence: 82%

“…8 In the same way, films of pure TiO 2 also exhibits a very irregular and cracked surface. 25 Both oxides when used as sensing films separately, i.e, in the pure form, presented a pH sensitivity around 58 mV/pH, which is near the Nernstian value. These results suggest that the interaction between V 2 O 5 and TiO 2 causes structural changes in the films, which in turn, leads to changes in the surface morphology and consequently in the sensing properties of the films.…”

Section: Resultsmentioning

confidence: 88%

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Vanadium and Titanium Mixed Oxide Films: Synthesis, Characterization and Application as Ion Sensor

Guidelli

Guerra

Mulato

2012

J. Electrochem. Soc.

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Vanadium/titanium mixed oxide films were produced using the sol-gel route. The structural investigation revealed that increased TiO 2 molar ratio in the mixed oxide disturbs the V 2 O 5 crystalline structure and makes it amorphous. This blocks the TiO 2 phase transformation, so TiO 2 stabilizes in the anatase phase. In addition the surface of the sample always presents larger amounts of TiO 2 than expected, revealing a concentration gradient along the growth direction. For increased TiO 2 molar ratios the roughness of the surface is reduced. Ion sensors were fabricated using the extended gate field effect transistor configuration. The obtained sensitivities varied in the range of 58 mV/pH down to 15 mV/pH according to the composition and morphology of the surface of the samples. Low TiO 2 amounts presented better sensing properties that might be related to the cracked and inhomogeneous surfaces. Rising the TiO 2 quantity in the films produces homogeneous surfaces but diminishes their sensitivities. Thus, the present paper reveals that the compositional and structural aspects change the surface morphology and electrical properties accounting for the final ion sensing properties of the V 2 O 5 /TiO 2 films.The development of the ion sensitive field effect transistor (ISFET) has been going on for almost 40 years. The device mimics a commercial MOSFET in which the metal gate electrode is removed, in order to expose the underlying insulator layer to the solution. Consequently, the gate insulator has the function of an ion selective electrode. 1 A modification to the ISFET configuration corresponds to the structure of the extended gate field effect transistor (EGFET), 2 which has a more flexible shape compared to ISFET, and also presents better long-term stability, since the ions from the chemical environment are excluded from any region close to the FET gate insulator. 3 The sensitive EGFET membrane is fabricated and attached to the end of the FET gate electrode. 2 Several kinds of materials and structures have been applied as the pH-sensing part of the EGFET. Among the materials used as membranes ruthenium oxide, 4 carbon nanotube, 5 SnO 2 , 6 ZnO 7 and V 2 O 5 xerogel 8 can be cited. In the search for alternative ion-sensing membranes to be employed in pH sensors, vanadium oxide stands out. This is because this transition-metal possesses a large number of oxidation states with possible redox-active properties. 9 The mixed oxide V 2 O 5 /WO 3 obtained by the sol-gel method has also been utilized as pH-sensor. It exhibited higher sensitivity than pure V 2 O 5 and underwent less degradation with continuous usage. 10 The best response was obtained for a 5% WO 3 molar ratio, for which the device worked linearly with the highest sensitivity. 10 Above 5% WO 3 molar ratio, the vanadium pentoxide seemed to dominate the process for acid solutions, while the tungsten oxide appeared to dominate in the case of basic solutions, giving rise to a non-linear EGFET response and decreased sensitivity. 10 The titanium oxide is also a v...

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Section: Resultssupporting

confidence: 82%

Section: Resultsmentioning

confidence: 88%

Vanadium and Titanium Mixed Oxide Films: Synthesis, Characterization and Application as Ion Sensor

Guidelli

Guerra

Mulato

2012

J. Electrochem. Soc.

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“…Among the types of photocatalyst, TiO 2 is mainly applied for degradation of organic pollutants because of low coast, nontoxic, chemical inert, photo-stability, high activity, no secondary contamination, availability and also, water insolubility in most condition (Shifu and Gengyu, 2005;Liao and Chou, 2009;Govindan et al, 2013). In photocatalytic mechanism TiO 2 /UV light: In TiO 2 under irradiation UV light with k < 380 nm, electrons from the valence band are excited to the conduction band, result this procedures in valence band holes and in conduction band electrons generated.…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic degradation of paraquat herbicide in the presence TiO 2 nanostructure thin films under visible and sun light irradiation using continuous flow photoreactor

et al. 2015

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“…This separate scheme has many advantages to solve ISFET drawbacks, such as the flexibility of developing sensing element, simple to package, and suitable for disposable application. A variety of metal oxides have been developed as sensing film for EGFET-pH sensor including ZnO [13], [14], SnO 2 [15], Nb 2 O 5 [16], IrO X [17], TiO 2 [18], Ta 2 O 5 [19], PtO 2 [20] and ITO [21]- [26]. Meanwhile, many biosensors have been developed using EGFET structure, such as label-free DNA detection [27], glucose [28] and urea sensor [29], [30].…”

Section: Introductionmentioning

confidence: 99%

High Performance EGFET-Based pH Sensor Utilizing Low-Cost Industrial-Grade Touch Panel Film as the Gate Structure

Lin

2015

IEEE Sensors J.

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This paper develops a high performance extended-gate field-effect-transistor-based pH sensor utilizing industrial-grade touch panel film (TPF) as the sensing material. The TPF is composed of a polyethylene terephthalate substrate coated with an indium tin oxide, a silicon dioxide, and a niobium pentoxide (ITO/SiO 2 /Nb 2 O 5 ) layers. Since industrial roll-to-roll process is used to produce the TPF such that the cost and the quality for the film are very competitive for producing disposable sensors. Results show the developed sensor exhibits high sensitivity of 59.2 mV/pH in the range of pH from 3 to 13 with a good linearity of R 2 = 0.9948. It also shows excellent sensing performance including ultrafast response (∼1 s), good repeatability (variation ∼2%), and stability (variation ∼1%). When interfered with high concentration Na + ions (0.1 M) by adding normal saline water, the response increases slightly and sustain linearity. In addition, the performance of the developed sensor owing to sensing area change is evaluated that presents good linearity and consistent in the sensing areas range 11 2 ∼20 2 mm 2 . Accordingly, the developed TPF-based pH sensor has presented its potentials for rapid and low-cost hydrogen ion detections.Index Terms-EGFET, touch panel film, pH sensor, ITO, hydrogen ion.

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Preparation and characterization of the titanium dioxide thin films used for pH electrode and procaine drug sensor by sol–gel method

Cited by 71 publications

References 25 publications

Vanadium and Titanium Mixed Oxide Films: Synthesis, Characterization and Application as Ion Sensor

Vanadium and Titanium Mixed Oxide Films: Synthesis, Characterization and Application as Ion Sensor

Photocatalytic degradation of paraquat herbicide in the presence TiO 2 nanostructure thin films under visible and sun light irradiation using continuous flow photoreactor

High Performance EGFET-Based pH Sensor Utilizing Low-Cost Industrial-Grade Touch Panel Film as the Gate Structure

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