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Copper incorporation in Mn2+-doped Sn2S3 nanocrystals and the resultant structural, optical, and electrochemical characteristics
(2018-08-15)
Noppakuadrittidej, Prae
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Vailikhit, Veeramol
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Teesetsopon, Pichanan
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Choopun, Supab
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Tubtimtae, Auttasit
Sn<inf>2</inf>S<inf>3</inf> nanocrystals (NCs) with both Mn2+ doping and Cu2+ incorporation were synthesized using a chemical bath deposition method. The Cu2+ ions formed an anorthic Mn2+-doped Cu<inf>2</inf>SnS<inf>3</inf> structure with E<inf>g</inf> = 1.44 eV, which altered the material's optical and photo/electrochemical properties. After coating the bare Nb<inf>2</inf>O<inf>5</inf> electrode with Mn2+-doped Sn<inf>2</inf>S<inf>3</inf> or Mn2+-doped Cu<inf>2</inf>SnS<inf>3</inf> NCs, the photoluminescence spectrum was blue-shifted to 411.13 nm from 411.69 nm. Compared to the sample without Cu2+, the Cu2+-incorporated sample showed a slightly stronger emission at the same position, possibly due to disorder in the crystalline structure based on variations at the interface of Mn2+-doped Cu<inf>2</inf>SnS<inf>3</inf> NCs. Electrochemical analysis showed a lower charge transfer resistance in the Mn2+-doped Cu<inf>2</inf>SnS<inf>3</inf>, which is related to its larger electroactive surface area. The larger electroactive surface area is attributed to the Faradaic redox processes at the electrode surface, which suppresses the carrier recombination. The coexistence of Cu2+ and Mn2+ ions shortened the electron transport pathway at the interface and improved the carrier diffusion coefficient and diffusion length, leading to a higher specific capacitance that implies higher energy storage performance. Finally, the I-V characteristics of the Mn2+-doped Cu<inf>2</inf>SnS<inf>3</inf>-coated Nb<inf>2</inf>O<inf>5</inf> electrode under various light illumination conditions indicated its better efficiency in photoresponse, electron generation, and charge collection, owing to a superior charge transport mechanism. Detailed results were obtained about the charge dynamics in the as-prepared photo/electrochemical devices with Cu2+ incorporation in the Mn2+-doped SnS<inf>3</inf> electrode.
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High sensitive nanocrystal titanium nitride EG-FET pH sensor
(2013-10-29)
Rayanasukha, Yossawat
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Porntheeraphat, Supanit
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Bunjongpru, Win
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Khemasiri, Narathon
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Pankiew, Apirak
Solid state pH-sensor device with high efficiency has successfully prepared by using TiN thin film as sensing membrane of extended gate field effect transistor (EG-FET) device. This research has described the physical properties and sensing characteristics of TiN membrane thin film which deposited on SiO<inf>2</inf>/Si substrate through reactive D.C. magnetron sputtering system. Thenanocrytal-TiNwith anatasestructure depended on substrate heating conditions was revealed from glancing angle x-ray diffraction. The I<inf>DS</inf>-V<inf>GS</inf> measurement in the standard buffer solutions showed that the sensitivity of fabricated TiN-EGFET pH deviceis 59.82mV/pH. © (2013) Trans Tech Publications, Switzerland.
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In situ ring-opening polymerization of hydroxyapatite/poly(ethylene adipate)-co-(ethylene terephthalate) biomimetic composites
(2013-02-01)
Siriphannon, Punnama
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Monvisade, Pathavuth
Hydroxyapatite/poly(ethylene adipate)-co-poly(ethylene terephthalate) biomaterials (HAp/PEA-co-PET) have been prepared by ring opening polymerization (ROP) of cyclic oligo(ethylene adipate)-co-oligo(ethylene terephthalate) (C-OEA-co-C-OET) in the porous hydroxyapatite (HAp) scaffolds at 250 °C for 24 h under vacuum. The content of ROP-PEA-co-PET in the HAp/PEA-co-PET composite was about 20 wt% with the values of number average molecular weight (Mn) and weight average molecular weight (MW) of 3380 and 7160 g/mol, respectively. Compressive strength and modulus of the HAp/PEA-co-PET composites were about 29 and 246 MPa, respectively. These mechanical properties were higher than those of the porous HAp templates and natural cancellous bone. In vitro bioactivity of the HAp/PEA-co-PET composites was studied by soaking in simulated body fluid (SBF) under the flowing system at the rate of 130 mL/day for 7, 14, 21 and 28 days. The formation of hydroxyapatite nanocrystals was observed on the composite surfaces through the consumption of calcium and phosphorus from the SBF solution, indicating the bioactivity of these HAp/PEA-co-PET composites. These results indicated the competency of HAp/PEA-co-PET composites for biomedical applications. © Indian Academy of Sciences.
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Oxygen control on nanocrystal-AION films by reactive gas-timing technique R.F. magnetron sputtering and annealing effect
(2008-12-01)
Bunjongpru, W.
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Pomtheeraphat, S.
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Somwang, N.
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Khomdet, P.
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Hruanun, C.
The AlON films grown on Si(100) substrates by using radio frequency (r.f.) magnetron sputtering from high purity aluminum (99.999% Al) target with a novel reactive gas-timing technique. The 100 nm thick of AlON films were deposited with 200 watts r.f. power and the substrate temperature is maintained at room temperature by the technique of gas-timing which varying flow-in sequence of high purity of Ar (99.999%) and N<inf>2</inf> (99.9999%) gases fed into the sputtering chamber at 10:90 (sec) ratio. The composition and crystal orientation of AlON films affected by gas-timing of Ar and N<inf>2</inf> were analyzed by Auger Electron Spectroscopy (AES) and Xray diffraction (XRD). The oxygen atoms revealed by AES formed into a corporation in films was studied. This suggests that the oxygen contamination formed as A10<inf>x</inf>N<inf>y</inf> compound may due to the residual oxygen in base pressure of 10-7 mbar and higher reactivity of oxygen in the reactor compared to nitrogen. The gas-timing technique used in the sputtering growth system shows the advantage of the oxygen quantity control, while the general sputtering process (without gas-timing technique) shows an increase of the oxygen composition depended on film thickness. The characterizations results clearly indicate that the gas-timing r.f. magnetron sputtering technique plays an important role to control the incorporation of oxygen and to form the nanocrystalaluminum oxynitride films which very attractive for various sensors applications. © 2008 Trans Tech Publications, Switzerland.
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