Controlled Synthesis, LSPR Properties And Catalytic Activity Of Non-stoichiometric Copper Selenide Nanoparticles

As an important representative of chalcogenide semiconductor, copper selenide with special optical properties, still suffer from a certain difficulty in its preparation, greatly limiting its application in biochemical analysis. In recent years, the localized surface plasmon resonance (LSPR) properties induced by doping is of great concern, especially copper deficient copper chalcogenides with increasing carrier concentration exhibit LSPR absorption in near-infrared area. Therefore, the special optical properties of copper chalcogenide nanocrystals attract much more attention. Copper selenide, as a new type of plasmon resonance materials, has advantages of low prices, low biological toxicity and good semiconductor property, providing for a certain potential applications. However, the study of the controllable synthesis, catalytic activity and tuning LSPR of copper selenide are still in an early research stages. Here, a controllable, simple and green preparation method of copper selenide was established. Moreover, the regulation factors of the LSPR. special optical properties and catalytic activity, as well as its applications in biochemical analysis have been further discussed. The research contents include the following:(1) The controllable size and monodispersed copper selenide nanoparticles (Cu2_xSeNPs) was obtained by room temperature synthesis method with a simple redox reaction assisted by surfactants. This method is of low cost and simple operation. Cu2-xSeNPs was characterized by UV-visible absorption spectroscopy. transmission electron microscopy. X-ray diffraction spectroscopy. which suggest that the obtained Cu2-xSeNPs exhibits various excellent optical properties and display strong absorption in the near-infrared region, and the absorption is consistent with localized surface plasmon resonance properties. At the same time. LSPR can be tuned by controlling the reaction time, temperature and solvent, demonstrating that LSPR response depends not only on the composition, but also the oxidant, the temperature and medium environment. These provide new opportunities for the development of infrared window and the light battery. It was also studied the photothermal conversion effect, dark field light scattering properties and the Raman enhancement properties of Cu2-xSeNPs, indicating it a very good photothermal agent and Raman enhanced substrate. These suggest that Cu2-xSeNPs is a kind of important optical materials, presenting great significance for the application in the field of photoelectric sensors and biochemical analysis.(2) As a new plasmon resonance material, Cu2-xSeNPs were applied to the detection of lysozyme (Lys). The synthesized Cu2-xSeNPs not only show good monodispersity and uniformity, but also have a narrow plasmon resonance absorption peak. Lys was used to induce aggregation of Cu2-xSeNPs producing violent coupling effect between nanoparticles, and the LSPR can be adjusted controllably as different concentration of Lys can cause different degree of coupling. At the same time, the concentration of Lys show a good linear relationship with the changes of LSPR. which makes Cu2-xSeNPs become a new infrared sensor for ultra trace detection of Lys. Under high salt concentration. Lys with high pI can rapidly induce the aggregation of PSS stabilized Cu2-xSeNPs, causing obvious change of near infrared absorption and scattering light signal, which can be clearly observed by dynamic light and scanning electron microscope. This method is simple, rapid and sensitive, further developing the application of LSPR in copper chalcogenide nanocrystals.(3) Cu2-xSeNPs having its special crystal structure, can greatly enhance the catalytic effect of catalytic system. In the tetramethylbenzidine hydrogen peroxide system, terephthalic acid hydrogen peroxide system and luminol hydrogen peroxide system, Cu2-xSeNPs exhibit different catalytic capabilities. The catalytic performance not only depend on the affinity of Cu2-xSeNPs to the substrate, but also on the special crystal structure of Cu2-xSeNPs. We show that Cu2-xSeNPs possess intrinsic catalytic activity to decompose H2O2to be active OH radical in the catalytic process, and found that the ability of Cu2-xSe to decompose hydrogen peroxide was different in acidic and alkaline conditions through the EPR experiment, which further enriched the research of catalytic activity of non-stoichiometric Cu2-xSeNPs. At the same time, we apply the 1HA-H2O2-Cu2-xSe fluorescence system for highly sensitive detection of H2O2and glucose with efficient sensitivity to the level of micro molar with a wide detection range.As the above results shown, we develop a method of controllable synthesis of copper selenide nanocrystals. providing a more simple method of studying the optical properties of copper chalcogenides in biochemical analysis. The study further explored the localized surface plasmon resonance properties of copper chalcogenides caused by defects, greatly developing the regulation on the optical properties of semiconductors. It also was explored the catalytic properties of copper selenide enrishing the catalytic theory of semiconductor to further expand its application in analytical chemistry and energy materials or other related fields.