Papers by Author: Fu Qiang Huang

Abstract: The Formation of Heterojunction Structure between Two Semiconductors Was Considered as an Effective Method to Enhance the Photocatalytic Activity. here, we Reported a Simple Method to Prepare SnS₂/SnO₂ Heterojunction Photocatalysts by Annealing SnS₂ in Air. the Structure, Morphology, Chemical Compositions and Optical Properties of the Obtained Materials Were Characterized by the X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Energy-dispersive X-ray Spectroscopy (EDX) and Ultraviolet-visible-near Infrared (UV-Vis-NIR) Absorption Spectra. the Photocatalytic Investigations Showed the Composites Have Higher Photocatalytic Activity than the Single-phase SnS₂. the SnS₂ Powder which Annealed at 400 °C for 60 Min Showed the Highest Photocatalytic Performance.

Abstract: The effect of N₂ gas pressure during the rapid thermal process (RTP) on the structural and morphological properties of CIGS films was investigated. The precursor was prepared by sputtering from a single quaternary CIGS target. XRD characterization demonstrated that there were two phase of CuIn_0.7 Ga_0.3 Se₂ and Ga-rich CuIn_{Subscript text}1-xGaxSe_{Subscript text}2 chalcopyrite structure in all of the selenized CIGS films. Too low and too high N₂ gas pressure induced compact but small grain-size morphologies due to the insufficient Se supply. Furthermore, all of the samples exhibited delaminated cross-sectional morphologies. Finally, Photovoltaic devices prepared from absorbers selenized under 4 Torr N₂ gas pressure resulted in efficiency of 4.8%.

Abstract: The intermediate bands materials CuGa1-xQxS2 (Q = Ge, Sn) were investigated, and the narrow half-filled intermediate bands were successfully introduced into the chalcopyrite CuGaS2 when Ga3+ ion were partially replaced by Ge4+(Sn4+) impurities. The absorption edge of CuGa1-xQxS2 red shifts greatly with the increasing in the doping content due to the form of Ge-4s (Sn-5s) and S-3p hybridization orbits intermediate band, even small Q-doping content(2mol %), considerable red shifts are still achieved. CuGa1-xQxS2 (Q = Ge, Sn) with IBs extend the range of solar spectrum and could be the excellent candidates for the theoretical predictions of enhanced solar cell efficiency.

Abstract: A series of layered-structure Bi-based oxychlorides such as BiOCl, Bi3O4Cl, Na0.5Bi1.5O2Cl, Bi4NbO8Cl and MBiO2Cl (M = Ca, Sr, Ba, Cd, Pb) used as efficient photocatalysts. Among them, Bi3O4Cl (Eg = 2.79 eV), Na0.5Bi1.5O2Cl (Eg = 3.03 eV), Bi4NbO8Cl (Eg = 2.38 eV) and PbBiO2Cl (Eg = 2.45 eV) are visible-light-responsive. The powders synthesized by solid state reactions were characterized by X-ray diffraction (XRD) and UV-Vis diffuse reflection spectrum. Their photocatalytic activities were evaluated by the degradation of methyl orange. The results generally show that the UV-induced photocatalytic performances of the novel oxychloride catalysts are better than or comparable to that of anatase TiO2. The high photocatalytic performance of Bi-based oxychlorides is mainly ascribed to the presence of strong internal static electric fields between layers.

Abstract: A series of Cu1-xAlS2 (x = 0 ~ 0.08) bulk samples were synthesized by spark plasma sintering. The electrical and optical properties were investigated. P-type conductions for all samples were confirmed by both positive Seebeck coefficient and Hall coefficient. Bulk undoped CuAlS2 had a high conductivity of about 0.9 S/cm with a large band gap of 3.4 eV at room temperature. For vacancy-doped in Cu site, the carrier concentration was highly enhanced, reaching 1.7 × 1019 cm-3 for 8 mol% doped sample, and without decreasing the bang gap. The introduction of vacancies destroys the continuity of Cu-S network, which decreases the Hall mobility.

Abstract: Eu-doped CaS phosphors were prepared from sulfurization of CaCO3 in H2S gas without flux. The doping of Eu activator was conducted in two different modes: synchronous doping during sulfurization of CaCO3 and subsequent doping by vacuumly calcinning pure CaS and Eu2O3. Comparison of the as-prepared samples indicated that subsequent doping led to larger optimum Eu concentration and lower red emission intensity than synchronous doping. The different luminescence properties are ascribed to the different activator distributions in CaS host induced by different doping modes, and the uniform distribution resulted from synchronous doping is beneficial to the luminescence of the phosphor.

Abstract: ZnS:Cu,Cl phosphors were synthesized by high temperature (1200 °C) solid state reaction, mechanical milling (rotation speed = 0, 75, 150, 250 and 350 r / min) and the final annealing at 750 °C for 1 h in different atmospheres (hydrogen sulfide, sealed evacuated silica tubes and Ar). The as-prepared phosphors were characterized by X-ray powder diffraction and photoluminescence spectra. It was found that mechanical milling led to width increases of diffraction peaks. Both the mechanical milling and atmosphere play important roles in the photoluminescence performance of the phosphors. Some phosphors prepared by the three-step method possess higher photoluminescence performances than the normal one-step method. Particularly, the luminescence intensity of the phosphor milled at the rotation speed of 75 r / min and then treated in Ar atmosphere is about one time higher than that prepared by the normal one-step process.