Cuprous oxide is a monovalent copper oxide which is a bright red powdery solid which is hardly soluble in water and is converted to divalent copper in an acidic solution. It is an important P-type semiconductor material with a band gap of only 2.1eV and a photoelectric conversion efficiency of 18%. In 1998, cuprous oxide was found to act as a catalyst for the decomposition of water into hydrogen and oxygen in sunlight, proving to be a promising photocatalytic oxidation material. Nowadays, with the development of nanomaterials, not only have the size and morphology of cuprous oxide micro-nanostructures been prepared, but also various morphology control theories such as quantum dots, nanowires, nanosheets, nanospheres, polyhedra , hollow structure, etc. Nano-sized Cu2O also has unique optical and magnetic properties, and has been widely used in photoelectric conversion, industrial catalysis and gas sensors.
Raman spectroscopy is to obtain molecular vibration and rotation by scattering light, so as to understand the structure, symmetry, electronic environment and molecular binding of molecules, which are often used for quantitative and qualitative analysis of the structure and composition of materials. In recent years, Raman spectroscopy has been gradually applied to the nondestructive testing and identification of surface pigments. The Raman spectroscopy of materials can be used to understand the chemical bonds, crystallization degree, lattice distortion, phase transformation and other information inside the crystal. This paper mainly analyzes the effect of doping on the Raman spectroscopy of cuprous oxide.
theory
Photoelectron experiments show that doping can significantly improve the photoelectric conversion performance of Cu2O nanotube array electrodes. Therefore, this paper mainly analyzes the Raman spectral characteristics of Cu2O nanowire doped composites with semiconductor properties. By judging the effects of changes in crystal structure on the internal vibration modes of the crystal by determining the doping and size reduction, these results can guide archaeologists to obtain more accurate and comprehensive results when using Raman detection techniques to identify the chemical composition of the surface of the artifact.
Cuprous oxide has a simple cubic lattice and belongs to the space group. Each unit cell contains two cuprous oxide molecules, as shown in the cell illustration in the figure. 1533629231965567.jpg
Theoretically, for a perfect cuprite-type cuprous oxide crystal, only Raman activity is available in its six modes of vibration. In fact, due to the existence of defects, not only the intensity of the intrinsic peak may be extremely low or even concealed, but the vibration mode of non-Raman activity can also be excited. The different structures and states of cuprous oxide can exhibit different Raman properties. . In the literature report of the existing cuprous oxide Raman spectroscopy, the single crystal cuprous oxide sample prepared by the method of melt cooling and high temperature oxidation has a completely different Raman response property to the chain hollow spherical cuprous oxide. It is attributed to crystal defects caused by directional bonding of the crystal growth process.
Raman Spectral Analysis of Cu2O Nanowires
Experimental equipment and parameter test equipment: Finder Vista micro-confocal Raman spectrometer system; laser wavelength is 532 nm;
From the Raman spectrum of cuprous oxide nanowires, the Raman peak of Cu2O nanometers is located at 45, 65, 513 and 1044 cm-1, and is also at 150 and 224 cm-1, 438, 738, 903 and 945 cm-1. There is a Raman characteristic peak. Compared with the literature, 150, 227, 513 and 903 cm-1 are the Raman characteristic peaks of Cu2O nanowires. The vibration at 150 cm-1 is an infrared active mode, which can be assigned to the mode excited by oxygen defects, and the 227 cm-1 minute belongs to the second-order frequency doubling vibration mode.
The Raman characteristic peak of ZnO is located at 437 cm-1. It can be inferred that the Zn and O elements form a ZnO structure after the 438 cm-1 Raman spectral characteristic peak is tested.
in conclusion
Compared with micron-sized materials, nano-multi-sized cuprous oxide exhibits novel and unique Raman optical properties due to its significant defects in microstructure and surface reconstruction of macrostructures. The smaller the size causes the crystal structure change to have a great influence on the change of the internal vibration mode of the crystal, which is reflected in the Raman spectrum, which shows that the number of vibration peaks, peak intensity and vibration peaks have changed. The phenomenon observed on cuprous oxide in this paper can also be applied to other typical oxide pigments, such as PbO, MnO and the like. These results can guide archaeologists to obtain more accurate and comprehensive results when using Raman detection techniques to identify the chemical composition of the surface of a cultural relic. At the same time, it also provides a visual explanation for the conclusion that nanomaterials have special properties that are not possessed by bulk materials.