Papers by Keyword: Solar Energy Materials

Abstract: ZnO:Al thin films were deposited on flexible substrates by magnetron sputtering. The effects of the carrier concentrations on the hall mobilities of AZO films were investigated. When the carrier concentration was high (~10²⁰/cm³), the hall mobility decreased with increase of the carrier concentration, showing obvious characteristics of ionized impurity scattering; moreover, the carrier mobility could be expressed to be-2.14/3 proportional of the carrier concentration by combining the results of simulation and experiments.simulation and experiment. When the carrier concentration was about a magnitude of 10¹⁹ cm^-3, the carrier mobility is influenced by the carrier concentration and grain size, which means the carrier mobility was affected by both the grain boundary scattering and ionized purity scattering mechanism.

Abstract: In this study, a novel strategy for preparation of Cu₂(M^II)(M^IV)S₄ thin films was creatively proposed. Three light absorption materials Cu₂MnSnS₄, Cu₂ZnSnS₄ and Cu₂ZnGeS₄ were successfully synthesized based on combustion method. It was found that the combustion synthesized powder is mainly consist of several metal oxides. The band gap energy of Cu₂MnSnS₄, Cu₂ZnSnS₄ and Cu₂ZnGeS₄ are determined to be 1.3 eV, 1.49 eV and 2.15 eV, respectively, showing a promising application on thin film solar cells. According to our experiment results, the combustion method was confirmed to be an efficient tool to synthesize various Cu-based absorber materials by using a post-sulfurization process, which provides a new view for fabrication of high-efficient low-cost photovoltaics.

Abstract: Cu₂ZnSnS₄ and Cu₂ZnGeS₄ thin films made from the earth abundant and non-toxic materials are quaternary semiconducting compounds which have received increasing interest for solar cells applications. Cu₂ZnSnS₄ and Cu₂ZnGeS₄ thin films have been synthesized by sulfurization of radio frequency magnetron sputtered precursors. The structural and optical properties of the thin films have been investigated and discussed. The result of X-ray diffraction demonstrates that the Cu₂ZnSnS₄ and Cu₂ZnGeS₄ thin films have kesterite (KS; space group I) crystal structure. An obvious blue shift is observed in the Raman spectra as smaller Ge replaces Sn. It is due to the fact that the radius of Ge cation is smaller than that of Sn cation , which results in the shrink of the lattice. Further transmission spectra demonstrate that the values of band gap for CZTS and CZGS thin films are 1.54 eV and 1.98 eV, respectively.

Abstract: Electron beam injection(EBI) is a process of gathering the electrons in materials using electron beam(EB). The EBI technology is proposed for purification of silicon particles by removing metal impurities through high-temperature oxidation, EBI, and HF acid washing processes. Analysis of silicon particle morphology after high-temperature oxidation using digital camera and after EBI using scanning electron microscope(SEM) were conducted. Then, the composition of silicon particles was analyzed using inductively coupled plasma(ICP). The silicon particle colours turned bright after EBI; therefore, EBI can change the thickness of SiO2 films in addition to increasing the temperature of the silicon particles. The results show that this technology is effective in removing metal impurities in silicon particles.