High pressure diamond and diamond-like carbon deposition using a microwave CAP reactor

McConnell, M.L.; Dowling, Denis P.; Pope, Conner; Donnelly, Kevin; Ryder, Alan G.; O'Connor, Gerard M.

doi:10.1016/s0925-9635(01)00637-9

Cited by 32 publications

(23 citation statements)

References 11 publications

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“…The microwave plasma sintering process known as rapid discharge sintering (RDS), was carried out using a circumferential antenna plasma (CAP) microwave system according to a procedure described in detail in Ref. [24]. Plasmas were formed at a pressure of 5 mbar in an Ar and O 2 (volume ratio: 10/1) atmosphere.…”

Section: Methodsmentioning

confidence: 99%

Electrochemical Characterization of Rapid Discharge Sintering (RDS) NiO Cathodes for Dye-Sensitized Solar Cells of <i>p</i>-Type

Novelli¹,

Awais²,

Dowling³

et al. 2015

AJAC

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Nickel oxide (NiO) thin films with thickness ranging in the interval 0.2 -3.5 μm have been deposited onto conductive transparent substrate via the method of plasma-assisted rapid discharge sintering (RDS) with microwave heating starting from NiO nanoparticles with diameter 50 nm. The optical and electrochemical properties of the RDS NiO films in the pristine state were characterized in non aqueous electrolyte with the solvent 3-methoxy-propionitrile (3-MPN). Upon electrochemical cycling of NiO in 3-MPN we observed two characteristic oxidation peaks referring to the two nickel centred processes Ni(II)→Ni(III) and Ni(III)→Ni(IV), which are both localized prevalently on the surface of the metallic oxide. The oxide films prepared with the RDS method were also sensitized with different types of commercial dyes, either organometallic (N719, black dye) or organic (squaraine 2, erythrosine B), to compare the corresponding p-type dye-sensitized solar cells (p-DSCs). All dyes here employed matched the energies of their frontier orbitals with the upper edge of NiO valence band and the redox level of the triiodide/iodide couple. The comparison of the performances of the p-DSCs based on RDS NiO which differed exclusively for the nature of the sensitizer showed that the extent of electronic conjugation in the structure of the dye is crucial for the control of the photovoltaic performance of the corresponding p-DSC.

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Section: Methodsmentioning

confidence: 99%

Electrochemical Characterization of Rapid Discharge Sintering (RDS) NiO Cathodes for Dye-Sensitized Solar Cells of <i>p</i>-Type

Novelli¹,

Awais²,

Dowling³

et al. 2015

AJAC

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“…The NiO x nanoparticles (~50 nm) were suspended in methanol (20 mg/ml) and the particulate layer NiO x is deposited by spraying using a similar technique to that described previously [33]. The microwave-assisted plasma sintering process known as rapid discharge sintering was carried out using a circumferential antenna plasma (CAP) microwave system described in detail elsewhere [34]. The plasma was formed at a pressure of 5 mbar in an argon and oxygen (10:1) atmosphere.…”

Section: Sample Preparation and Deposition Of Nio X Coatingsmentioning

confidence: 99%

Application of a novel microwave plasma treatment for the sintering of nickel oxide coatings for use in dye-sensitized solar cells

Awais

Rahman

MacElroy

et al. 2011

Surface and Coatings Technology

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In this study the use of microwave plasma sintering of nickel oxide (NiO x ) particles for use as ptype photoelectrode coatings in dye-sensitized solar cells (DSSCs) is investigated. NiO x was chosen as the photocathode for this application due to its stability, wide band gap and p-type 2 nature. For high light conversion efficiency DSSCs require a mesoporous structure exhibiting a high surface area. This can be achieved by sintering particles of NiO x onto a conductive substrate. In this study the use of both 2.45 GHz microwave plasma and conventional furnace sintering were compared for the sintering of the NiO x particles. Coatings 1 to 2.5 µm thick were obtained from the sintered particles (mean particle size of 50 nm) on 3 mm thick fluorine-doped tin oxide (FTO) coated glass substrates. Both the furnace and microwave plasma sintering treatments were carried out at ~450 ºC over a 5 minute period. Dye sensitization was carried out using Erythrosin B and the UV-vis absorption spectra of the NiO x coatings were compared. A 44% increase in the level of dye adsorption was obtained for the microwave plasma sintered samples as compared to that obtained through furnace treatments. While the photovoltaic performance of the DSSC fabricated using the microwave plasma treated NiO x coatings exhibited a tenfold increase in the conversion efficiency in comparison to the furnace treated samples. This enhanced performance was associated with the difference in the mesoporous structure of the sintered NiO x coatings.

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“…In the case of the latter, a circumferential antenna plasma (CAP) microwave system was used [19]. The chamber was first pumped down to 0.1 mbar at which point 50 sccm of nitrogen gas (99.998%) was introduced and the pressure was adjusted to 5 mbar using a manual throttle valve.…”

Section: Thermal Treatments -mentioning

confidence: 99%

Conversion of amorphous TiO2 coatings into their crystalline form using a novel microwave plasma treatment

Dang

Rahman

MacElroy

et al. 2011

Surface and Coatings Technology

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Crystalline titanium dioxide (TiO 2 ) coatings have been widely used in photoelectrochemical solar cell applications. In this study, TiO 2 and carbon-doped TiO 2 coatings were deposited onto unheated titanium and silicon wafer substrates using a DC closed-field magnetron 2 sputtering system. The resultant coatings had an amorphous structure and a post-deposition heat treatment is required to convert this amorphous structure into the photoactive crystalline phase(s) of TiO 2 . This study investigates the use of a microwave plasma heat treatment as a means of achieving this crystalline conversion. The treatment involved placing the sputtered coatings into a 2.45 GHz microwave-induced nitrogen plasma where they were heated to approximately 550°C.It was observed that for treatment times as short as 1 minute, the 0.25-µm thick coatings were converted into the anatase crystalline phase of TiO 2 . The coatings were further transformed into the rutile crystalline phase after treatments at higher temperatures. The doping of TiO 2 with carbon was found to result in a reduction in this phase transformation temperature, with higher level of doping (up to 5.8% in this study) leading to lower anatase-to-rutile transition temperature. The photoactivity performance of both doped and un-doped coatings heat-treated using both furnace and microwave plasma was compared. The carbon-doped TiO 2 exhibited a 29% increase in photocurrent density compared to that observed for the un-doped coating.Comparing carbon-doped coatings heat-treated using the furnace and microwave plasma, it was observed that the latter yielded a 19% increase in photocurrent density. This enhanced performance may be correlated to the differences in the coatings' surface morphology and band gap energy, both of which influence the coatings' photoabsorption efficiency.

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High pressure diamond and diamond-like carbon deposition using a microwave CAP reactor

Cited by 32 publications

References 11 publications

Electrochemical Characterization of Rapid Discharge Sintering (RDS) NiO Cathodes for Dye-Sensitized Solar Cells of <i>p</i>-Type

Electrochemical Characterization of Rapid Discharge Sintering (RDS) NiO Cathodes for Dye-Sensitized Solar Cells of <i>p</i>-Type

Application of a novel microwave plasma treatment for the sintering of nickel oxide coatings for use in dye-sensitized solar cells

Conversion of amorphous TiO2 coatings into their crystalline form using a novel microwave plasma treatment

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High pressure diamond and diamond-like carbon deposition using a microwave CAP reactor

Cited by 32 publications

References 11 publications

Electrochemical Characterization of Rapid Discharge Sintering (RDS) NiO Cathodes for Dye-Sensitized Solar Cells of &lt;i&gt;p&lt;/i&gt;-Type

Electrochemical Characterization of Rapid Discharge Sintering (RDS) NiO Cathodes for Dye-Sensitized Solar Cells of &lt;i&gt;p&lt;/i&gt;-Type

Application of a novel microwave plasma treatment for the sintering of nickel oxide coatings for use in dye-sensitized solar cells

Conversion of amorphous TiO2 coatings into their crystalline form using a novel microwave plasma treatment

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Electrochemical Characterization of Rapid Discharge Sintering (RDS) NiO Cathodes for Dye-Sensitized Solar Cells of <i>p</i>-Type

Electrochemical Characterization of Rapid Discharge Sintering (RDS) NiO Cathodes for Dye-Sensitized Solar Cells of <i>p</i>-Type