Nanocrystalline copper oxide (CuO) thin films were deposited onto glass substrates by a spin coating technique using an aqueous solution of copper acetate. These films were characterized for their structural, mor-phol...Nanocrystalline copper oxide (CuO) thin films were deposited onto glass substrates by a spin coating technique using an aqueous solution of copper acetate. These films were characterized for their structural, mor-phological, optoelectronic properties by means of X-ray diffraction (XRD) scanning electron microscopy (SEM), UVspectroscopy and four probe method. The CuO films are oriented along (1 1 1) plane with the monoclinic crystal structure. These films were utilized in H2S sensors. The dependence of the H2S response on the operating temperature, H2S concentration of CuO film (annealed at 700。C) was investigated. The CuO film showed selectivity for H2S. The maximum H2S response of 25.2 % for the CuO film at gas concentra-tion of 100 ppm at operating temperature 200oC was achieved.展开更多
Solar energy is becoming more popular and widespread, and consequently, the materials to manufacture solar cells are becoming more limited and costly. Therefore, in order to keep solar energy affordable and available,...Solar energy is becoming more popular and widespread, and consequently, the materials to manufacture solar cells are becoming more limited and costly. Therefore, in order to keep solar energy affordable and available, we must research alternative materials such as copper oxides. Some benefits of copper oxides include being available in abundance, affordable, low toxicity, low bandgap, and a high absorption coefficient—all of which contribute to it being a valuable interest for the manufacturing of solar cells. In this study, CuO thin films were synthesized utilizing RF sputtering technique with deposition occurring at room temperature followed by thermal annealing between 100°C and 400<span style="white-space:normal;">°</span>C and using different gases, oxygen (O<sub>2</sub>) (oxidizing and reactive gas) and nitrogen (N<sub>2</sub>) (inert gas), besides air. Afterwards, these thin films were evaluated for a range of wavelengths: 200 - 400 nm (UV spectrum), 400 - 700 nm (Visible spectrum), and 700 - 800 nm (IR spectrum), for both, optical transmittance and photoluminescence. In addition, the CuO results were compared to our Cu<sub>2</sub>O results from a previous study to assess their differences. In the results of this study, the CuO thin film initially had a bandgap of 2.19 eV at room temperature, and by increasing the annealing temperature to different levels, the bandgap decreased respectively. The presence of air in the chamber allowed for the highest decrease, followed by the nitrogen (N<sub>2</sub>) and the lowest decrease was observed in the presence of oxygen (O<sub>2</sub>). This was reflected in the decrease in the bandgap values from 2.19 eV (room temperature) to 2.05 eV for the films annealed at 400<span style="white-space:normal;">°</span>C.展开更多
文摘Nanocrystalline copper oxide (CuO) thin films were deposited onto glass substrates by a spin coating technique using an aqueous solution of copper acetate. These films were characterized for their structural, mor-phological, optoelectronic properties by means of X-ray diffraction (XRD) scanning electron microscopy (SEM), UVspectroscopy and four probe method. The CuO films are oriented along (1 1 1) plane with the monoclinic crystal structure. These films were utilized in H2S sensors. The dependence of the H2S response on the operating temperature, H2S concentration of CuO film (annealed at 700。C) was investigated. The CuO film showed selectivity for H2S. The maximum H2S response of 25.2 % for the CuO film at gas concentra-tion of 100 ppm at operating temperature 200oC was achieved.
文摘Solar energy is becoming more popular and widespread, and consequently, the materials to manufacture solar cells are becoming more limited and costly. Therefore, in order to keep solar energy affordable and available, we must research alternative materials such as copper oxides. Some benefits of copper oxides include being available in abundance, affordable, low toxicity, low bandgap, and a high absorption coefficient—all of which contribute to it being a valuable interest for the manufacturing of solar cells. In this study, CuO thin films were synthesized utilizing RF sputtering technique with deposition occurring at room temperature followed by thermal annealing between 100°C and 400<span style="white-space:normal;">°</span>C and using different gases, oxygen (O<sub>2</sub>) (oxidizing and reactive gas) and nitrogen (N<sub>2</sub>) (inert gas), besides air. Afterwards, these thin films were evaluated for a range of wavelengths: 200 - 400 nm (UV spectrum), 400 - 700 nm (Visible spectrum), and 700 - 800 nm (IR spectrum), for both, optical transmittance and photoluminescence. In addition, the CuO results were compared to our Cu<sub>2</sub>O results from a previous study to assess their differences. In the results of this study, the CuO thin film initially had a bandgap of 2.19 eV at room temperature, and by increasing the annealing temperature to different levels, the bandgap decreased respectively. The presence of air in the chamber allowed for the highest decrease, followed by the nitrogen (N<sub>2</sub>) and the lowest decrease was observed in the presence of oxygen (O<sub>2</sub>). This was reflected in the decrease in the bandgap values from 2.19 eV (room temperature) to 2.05 eV for the films annealed at 400<span style="white-space:normal;">°</span>C.
文摘采用水热法制备出了负载于钛片基材上的氧化铜薄膜,使用扫描电子显微镜(SEM)、X射线衍射仪(XRD)对样品进行了表征。SEM照片显示氧化铜薄膜由许多厚度约为10 nm的氧化铜纳米片所组成,XRD谱图显示氧化铜为面心立方结构。以水合肼还原对硝基苯酚为模型反应考察了所制备的薄膜催化剂的催化性能,研究发现催化过程中氢氧化钠用量对水合肼还原对硝基苯酚的速率有显著影响。在氢氧化钠用量为0.8-1.6克的范围内,对硝基苯酚还原速率随着氢氧化钠用量的增加显著增加,进一步增加其用量则导致对硝基苯酚还原速率的下降。表明动力学计算,Cu O/Ti催化水合肼还原对硝基苯酚反应的表观活化能仅为28.0 k J/mol,证实了所制备的薄膜催化剂具有很高的催化活性。
