Synthesis Of Copper Zinc Tin Sulfide Nanoparticles And Their Photoelectric Properties

In recent years, solar cells have attracted increasing attention due to the global environment and energy issues. High-efficiency, low-cost and environment-friend have been regarded as the requisite properties for the new generation solar cells materials. Quaternary chalcogenides Cu2ZnSnS4has a direct band gap of1.5eV, which is very close to the optimum band gap value of the absorb layer of solar cells. Also, Cu2ZnSnS4has a large absorption coefficient of104cm-1, and contain earth-abundant, low-cost and low toxicity elements. The theoretical limit for the photoelectric conversion efficiency of Cu2ZnSnS4thin film solar cell is nearly32.2%. Cu2ZnSnS4has been a promising absorber layer material for solar cells due to its excellent chemical, electronic and optical properties.Many kinds of methods have been used to prepare Cu2ZnSnS4thin films. However, these methods usually need to be processed under high-temperature or vacuum conditions, which lead to complicated operation and high-cost. Recently, the method dispersing prepared Cu2ZnSnS4nanoparticles in organic solvents to form a nanoparticle ink was developed. Cu2ZnSnS4thin film can be formed by coating the nanoparticle ink on a substrate. This has been one of the methods to prepare thin film solar cells fast, efficiently and low-costly.By choosing appropriate copper, zinc, tin precursors, sulfur source and solvents, Kesterite and Wurtzite Cu2ZnSnS4nanoparticles were synthesized separately using microwave-assisted method. XRD, Raman spectra, XRF, TEM, XPS, UV-Vis were utilized to study the characterization of the products. The differences between the products synthesized by microwave-assisted method and oil bath heating method were compared. The impacts of reaction time to the crystal structure, element ratio and morphological structure were studied. Cu2ZnSnS4thin films were fabricated by using nanoparticle ink method and annealed under different temperature. Their photoelectric effects were also tested primarily. The results showed that, using microwave irradiation to prepare Cu2ZnSnS4nanoparticles is a simple method by which we can obtain production in just one step. In addition, this method also has advantages such as facile reaction conditions, open-air condition at a lower temperature; short reaction time, high reproducibility and high yields. Cu2ZnSnS4nanoparticles synthesized by microwave-assisted method have controllable components, high crystallinity and are uniform in particle size. The products have a band gap close to the optimum band gap value of the absorb layer of solar cells and can be used as absorb layer of thin film solar cells.