Optical and Structural Properties of Titanium Dioxide Films from and Starting Materials Annealed at Various Temperatures

Shei, Shih–Chang

doi:10.1155/2013/545076

Cited by 17 publications

(7 citation statements)

References 17 publications

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“…The E g values obtained were 3.54 eV (sample S1) and 3.64 eV (sample S2) [ 9 ]. This blue-shift of 0.10 eV observed in sample S2 can be attributed to a combination of two effects: (i) the scattering losses because of its rougher surface, and (ii) the possible higher number of oxygen defects/vacancies created during the growth as consequence of the slower deposition rates [ 37 ]. While in the proof-of-concept cells fabricated in this work the TiO 2 layers were deposited on the back contact, this tuning of band gap could be very beneficial for the design of rear-emitter solar cells.…”

Section: Resultsmentioning

confidence: 99%

Sputtered Ultrathin TiO2 as Electron Transport Layer in Silicon Heterojunction Solar Cell Technology

2022

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This work presents the implementation of ultrathin TiO2 films, deposited at room temperature by radio-frequency magnetron sputtering, as electron-selective contacts in silicon heterojunction solar cells. The effect of the working pressure on the properties of the TiO2 layers and its subsequent impact on the main parameters of the device are studied. The material characterization revealed an amorphous structure regardless of the working pressure; a rougher surface; and a blue shift in bandgap in the TiO2 layer deposited at the highest-pressure value of 0.89 Pa. When incorporated as part of the passivated full-area electron contact in silicon heterojunction solar cell, the chemical passivation provided by the intrinsic a-Si:H rapidly deteriorates upon the sputtering of the ultra-thin TiO2 films, although a short anneal is shown to restore much of the passivation lost. The deposition pressure and film thicknesses proved to be critical for the efficiency of the devices. The film thicknesses below 2 nm are necessary to reach open-circuit values above 660 mV, regardless of the deposition pressure. More so, the fill-factor showed a strong dependence on deposition pressure, with the best values obtained for the highest deposition pressure, which we correlated to the porosity of the films. Overall, these results show the potential to fabricate silicon solar cells with a simple implementation of electron-selective TiO2 contact deposited by magnetron sputtering. These results show the potential to fabricate silicon solar cells with a simple implementation of electron-selective TiO2 contact.

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Section: Resultsmentioning

confidence: 99%

Sputtered Ultrathin TiO2 as Electron Transport Layer in Silicon Heterojunction Solar Cell Technology

2022

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“…Details of Ti 2p, O 1s, and N 1s peaks in amorphous N-TiO 2 XPS spectra at 200 °C are summarized in Table 1. The peaks at 461.5 (Ti 2p 3/2 ) and 455.9 (Ti 2p 1/2 ) eV in the XPS spectra correspond to Ti 4+ and Ti 3+ ions, respectively [75,76,77]. …”

Section: Resultsmentioning

confidence: 99%

Photonic Band Gap and Bactericide Performance of Amorphous Sol-Gel Titania: An Alternative to Crystalline TiO2

et al. 2018

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In addition to its traditional application in white pigments, nanocrystalline titania (TiO2) has optoelectronic and photocatalytic properties (strongly dependent on crystallinity, particle size, and surface structure) that grant this naturally occurring oxide new technological applications. Sol-gel is one of the most widely used methods to synthesize TiO2 films and NPs, but the products obtained (mostly oxy-hydrated amorphous phases) require severe heat-treatments to promote crystallization, in which control over size and shape is difficult to achieve. In this work, we obtained new photocatalytic materials based on amorphous titania and measured their electronic band gap. Two case studies are reported that show the enormous potential of amorphous titania as bactericide or photocatalyst. In the first, amorphous sol-gel TiO2 thin films doped with N (TiO2−xNx, x = 0.75) were designed to exhibit a photonic band gap in the visible region. The identification of Ti-O-N and N-Ti-O bindings was achieved by XPS. The photonic band gaps were found to be 3.18 eV for a-TiO2 and 2.99 eV for N-doped a-TiO2. In the second study, amorphous titania and amine-functionalized amorphous titania nanoparticles were synthetized using a novel base-catalysed sol-gel methodology. All the synthesized amorphous TiO2 nanoparticles exhibit bactericide performance (E. coli, ASTME 2149-13).

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“…Using a Ti 3 O 5 tablet as a starting material, we then performed e-beam evaporation at a working pressure of approximately 0.1 Torr to produce TiO 2 films with thicknesses of 10 nm, 20 nm, 30 nm, and 40 nm. The reaction equation is as follows [30,31]:2Ti3O5+O2→6TiO2…”

Section: Methodsmentioning

confidence: 99%

The Response of UV/Blue Light and Ozone Sensing Using Ag-TiO2 Planar Nanocomposite Thin Film

Shih

2019

Sensors

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We successfully fabricated a planar nanocomposite film that uses a composite of silver nanoparticles and titanium dioxide film (Ag-TiO2) for ultraviolet (UV) and blue light detection and application in ozone gas sensor. Ultraviolet-visible spectra revealed that silver nanoparticles have a strong surface plasmon resonance (SPR) effect. A strong redshift of the plasmonic peak when the silver nanoparticles covered the TiO2 thin film was observed. The value of conductivity change for the Ag-TiO2 composite is 4–8 times greater than that of TiO2 film under UV and blue light irradiation. The Ag-TiO2 nanocomposite film successfully sensed 100 ppb ozone. The gas response of the composite film increased by roughly six and four times under UV and blue light irradiation, respectively. We demonstrated that a Ag-TiO2 composite gas sensor can be used with visible light (blue). The planar composite significantly enhances photo catalysis. The composite films have practical application potential for wearable devices.

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Optical and Structural Properties of Titanium Dioxide Films from and Starting Materials Annealed at Various Temperatures

Cited by 17 publications

References 17 publications

Sputtered Ultrathin TiO2 as Electron Transport Layer in Silicon Heterojunction Solar Cell Technology

Sputtered Ultrathin TiO2 as Electron Transport Layer in Silicon Heterojunction Solar Cell Technology

Photonic Band Gap and Bactericide Performance of Amorphous Sol-Gel Titania: An Alternative to Crystalline TiO2

The Response of UV/Blue Light and Ozone Sensing Using Ag-TiO2 Planar Nanocomposite Thin Film

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