- Influence of SnO2 addition on the thermoelectric properties of Zn1 - xSnxO (0.01 ≤ x ≤ 0.05)
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The grain size and the density of the Zn1 - xSnxO (0 ≤ x ≤ 0.05) samples decreased with increasing SnO2 content. The addition of a small amount of SnO2 (x ≤ 0.01) to ZnO led to an increase in both the electrical conductivity and the absolute value of the Seebeck coefficient, resulting in a significant increase in the power factor. The thermoelectric power factor was maximized to a value of 1.25 × 10-3 Wm-1 K-2 at 1073 K for the Zn0.99Sn0.01O sample.
- Park,Seong,Kwon,Nahm,Cho
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- Growth and characterization of Sn doped ZnO thin films by pulsed laser deposition
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Sn:ZnO thin films with different Sn concentrations were grown by pulsed laser deposition (PLD) onto single-crystal Si(001) substrates at an oxygen pressure of 2 × 10-2 mbar and substrate temperature of 600 °C. The targets used were high density Sn:ZnO pellets with different Sn concentrations produced by mixing ZnO and SnO2 by conventional ceramic routes. A deep structural and electrical characterization was carried out in order to determine the role of an increasing Sn nominal concentration on the ZnO film transport properties. Only films with a nominal 0.1 at% Sn show an improvement of the transport properties, lower resistivity and higher donor concentration, with respect to pure ZnO thin films. For films with larger Sn nominal concentrations segregated SnZnO phases appear that lead to larger film resistivities and no increase in donor concentration. The 0.1 at% Sn film is accordingly a good candidate to study the possible room temperature ferromagnetism when co doping with Mn.
- Lopez-Ponce,Costa-Kraemer,Martin-Gonzalez,Briones,Fernaendez,Caballero,Villegas,De Frutos
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- Gold-tin co-sensitized ZnO layered porous nanocrystals: enhanced responses and anti-humidity
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High responses and good selectivity are key sensing properties of metal oxide (MOX) gas sensors. However, it is still a major challenge for a single MOX gas sensor to achieve both of them. Specially, the research in the field of high performance gas sensors has been hindered by negative effects of the typical interference, relative humidity (RH). In this paper, we report the successful preparation of gold-tin co-sensitized ZnO layered porous nanocrystals (Au-5Sn-ZLPCs) via a sequential solvothermal reaction and deposition-reduction method. Based on Sn dopants sensitized ZLPCs, the introduction of Au decoration can act as a secondary sensitized element on the crystal surfaces of ZnO. The special synergy between noble metals and oxides can introduce additional catalytic effects to further improve sensing properties. As a result of Au-Sn co-sensitization, sensing properties of sensors towards reducing VOC gas were significantly enhanced, while those towards oxidizing ozone gas were different to each other. Besides the typical sensing properties including responses, operating temperature, response & recovery properties, etc., Au-Sn co-sensitized samples significantly reduced negative effects of RH on responses to both reducing and oxidizing gases (good anti-humidity).
- Yao, Ming-Shui,Cao, Lin-An,Hou, Guo-Lin,Cai, Min-Lan,Xiu, Jing-Wei,Fang, Chen-Hao,Yuan, Fang-Li,Chen, Yun-Fa
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- Solid-state dye-sensitized solar cells based on Zn1-: XSnxO nanocomposite photoanodes
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Solid-state dye-sensitized solar cells (ss-DSSCs) comprising Sn2+-substituted ZnO nanopowder were purposefully tailored via a co-precipitation method. The solar cells assembled in this work were sensitized with N719 ruthenium dye and insinuated with spiro-OMeTAD as a solid hole transport layer (HTL). Evidently, significant enhancement in cell efficiency was accomplished with Sn2+ ions-substituted ZnO photoelectrodes by maintaining the weight ratio of SnO at 5%. The overall power conversion efficiency was improved from 3.0% for the cell with pure ZnO to 4.3% for the cell with 5% SnO substitution. The improvement in the cell efficiency with Sn2+-substituted ZnO photoelectrodes is attributed to the considerably large surface area of the nanopowders for dye adsorption, efficient charge separation and the suppression of charge recombination provided by SnO. Furthermore, the energy distinction between the conduction band edges of SnO and ZnO implied a type II band alignment. Moreover, the durability as well as the stability of 15 assembled cells were studied to show the outstanding long-term stability of the devices made of Sn2+ ion substituted ZnO, and the PCE of each cell remained stable and ~96% of its primary value was retained for up to 100 h. Subsequently, the efficacy was drastically reduced to ~35% after 250 h of storage.
- El-Shazly, Ayat Nasr,Shalan, Ahmed Esmail,Rashad, Mohamed Mohamed,Abdel-Aal, Elsayed Ali,Ibrahim, Ibrahim Ahmed,El-Shahat, Mohamed F.
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p. 24059 - 24067
(2018/07/13)
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- A novel type heterojunction photodiodes formed junctions of Au/LiZnSnO and LiZnSnO/p-Si in series
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Lithium-zinc-tin-oxide thin films were prepared by sol gel method. The structural and optical properties of the films were investigated. The optical band gaps of the LiZnSnO films were found to be 3.78 eV for 0 at.% Li, 3.77 eV for 1 at.% Li, 3.87 eV for 3 at.% Li and 3.85 eV for 5 at.% Li, respectively. Au/LiZnSnO/p-Si/Al photodiodes were fabricated using a lithium-zinc-tin-oxide (LZTO, Li-Zn-Sn-O) layer grown on p-Si semiconductor. The electrical characteristics of the photodiodes were analyzed by current-voltage, capacitance-voltage and conductance-voltage measurements. The reverse current of the diodes increases with both the increasing illumination intensity and Li content. It was found that the Li-doped ZTO photodiodes exhibited a better device performance than those with an undoped ZTO.
- Aydin, H.,Yakuphanoglu, F.,Tatarolu, A.,Al-Ghamdi, Ahmed A.,El-Tantawy, Farid,Farooq, W. A.
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