This research work reports the synthesis of copper (II) oxide (CuO) nanoparticles using the wet chemical co-precipitation method. The synthesised nanoparticles were characterised using ultraviolet–visible spectroscopy, X-ray diffraction, field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy and high-resolution transmission electron microscopy in terms of absorption, crystal structure and size, morphology and elemental composition, and particle size. The existence of functional groups was verified by Fourier transform infrared spectroscopy. The synthesised copper (II) oxide nanoparticles showed an absorption peak at 397 nm, and a Tauc’s plot study showed a band-gap energy of 3.2 eV. The effects of varied excitation energies – namely, 3.81 and 3.54 eV – on the emission spectra of rod-shaped nanoparticles were assessed through photoluminescence spectroscopy, and the release of red, orange, green, violet and yellow colours was observed. The voltage–current characteristics of nanoparticle pellets were measured using a two-probe technique. The increase in the direct-current electrical conductivity of pellets heated at 100 and 200°C was ascertained. Overall, this research work provides valuable insights into the electronic properties of copper (II) oxide nanoparticles, which could have potential applications in various fields such as catalysis and electronics.

中文翻译：

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氧化铜纳米棒的激发波长依赖性光致发光/电导率

这项研究工作报告了使用湿化学共沉淀法合成氧化铜（II）（CuO）纳米粒子。使用紫外可见光谱、X射线衍射、场发射扫描电子显微镜、能量色散X射线光谱仪和高分辨率透射电子显微镜对合成的纳米粒子进行了表征，包括吸收、晶体结构和尺寸、形貌和元素组成和粒径。通过傅里叶变换红外光谱验证了官能团的存在。合成的氧化铜 (II) 纳米粒子在 397 nm 处显示出吸收峰，Tauc 绘图研究显示带隙能为 3.2 eV。通过光致发光光谱评估了不同激发能量（即 3.81 和 3.54 eV）对棒状纳米粒子发射光谱的影响，并观察到红色、橙色、绿色、紫色和黄色的释放。使用双探针技术测量纳米粒子颗粒的电压-电流特性。确定了在 100 和 200°C 下加热的颗粒的直流电导率的增加。总的来说，这项研究工作为氧化铜（II）纳米粒子的电子特性提供了有价值的见解，它可能在催化和电子等各个领域具有潜在的应用。