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A facile ion-exchange assisted chemical bath deposition of CuSbS 2 for thin film solar cells and exploration of chemical bath mechanism, which achieved the champion efficiency in chemical bath deposition of CuSbS 2 solar cells and enriched the environmentally friendly inorganic solar cell preparation process. [Display omitted] • A facile ion-exchange assisted chemical bath deposition is firstly explored for CuSbS 2 compound. • Pure phase CuSbS 2 thin films with uniform and crystalline were prepared. • Achieved a champion efficiency of 0.75% for CBD-based CuSbS 2 solar cells. Copper antimony sulfur (CuSbS 2) possesses a band gap of about 1.5 eV, high absorption coefficient of > 104 cm−1 and abundant compositions, which is considered as one of the potential photovoltaic absorbers. In this work, we propose a facile ion-exchange assisted chemical bath deposition (IEACBD) method, which uses Cu+ to replace Sb3+ from the matrix of Sb 2 S 3 and then combine into CuSbS 2 alloy. Through systematic study, we found that this ion-exchange is a simultaneous interdiffusion process of Cu+ and Sb3+ ions, which enables a uniform mixture of those two elements. But it also inevitably produces a Sb 2 O 3 by-product on the surface of the film because of the alkaline environment of this chemical bath. To further remove it, we introduce a mild etching process with BDCA solution for Sb 2 O 3 and then obtain a high-quality CuSbS 2. Finally, we assemble an inorganic CuSbS 2 solar cell with the architecture of FTO/TiO 2 /CdS/CuSbS 2 /Carbon/Ag, and delivering a photoelectric conversion efficiency of 0.75 %. This enriches the preparation method of CuSbS 2 thin film and also provides guidance for the synthesis of the similar multiple chalcogen compounds. [ABSTRACT FROM AUTHOR]

Abstract Ternary compound semiconductor CdSe x S 1-x (x = 1, 0.8, 0.6, 0.4, 0.2 and 0) thin films were prepared on glass substrates by using simple solution processed spin coating technique. Cadmium acetate, sodium selenosulfate and thiourea were used as source materials for Cd2+, Se2− and S2− ions, while triethanolamine was used as a capping agent. The 25% concentred NH 4 OH solution was used as a complex reagent and also used to adjust the pH of the final solution ~ 11. The deposition conditions (rotation speed 2000 rpm for 30 s and substrate dried in the air at 120 °C for 2 min) were remain same for all the samples. The as-deposited thin films on glass substrate were annealed at 350 °C for 30 min. The X-ray diffraction pattern shows that all the samples were polycrystalline in the nature with hexagonal structure. The most of prepared thin films were highly textured along (002) plane and peak position for plane (002) is shifted with change in composition 'x'. The average crystallite size in CdSe x S 1-x thin films were found between 62.6 nm to 93.4 nm. Scanning electron microscopy images showed uniform deposition morphology with spherical shaped grains distributed over entire glass substrate. Samples CdSe 0.8 S 0.2 and CdSe 0.6 S 0.4 thin films indicated interesting morphological features with the combination of spherical shaped nanoparticles and interconnected nanofibers which form hierarchical flowerlike microstructure. Energy dispersive X-Ray studies confirmed that thin films were having approximately same stoichiometry of atomic ratio of elements Cd, Se and S as present in volumetric ratio of the reactants in chemical solution. Fourier transform infrared studies confirmed the formation of the Cd(Se,S) bonding in materials. The optical band gap of CdSe x S 1-x thin films were found as direct band gap in the range of 1.82 eV to 2.32 eV. As the incorporation of sulphur element increases, the band gap of CdSe x S 1-x thin film also increases. The CdSe x S 1-x thin films can be used as absorption layer in solar photovoltaic cell which is due to wide and fine tenability of the energy band gap. Highlights • Simple, fast and convenient technique to produce uniform CdSe x S 1-x thin films. • Minimum material wastage, low cost and easily obtain desirable thickness method. • Spherical shape nanoparticles with interconnected nanofibers features. • Optical band gap tuned from 1.82 eV to 2.32 eV as incorporation of sulphur increased. [ABSTRACT FROM AUTHOR]

The microstructure of absorption layer at the liquid–solid interface in nanofluids is investigated by molecular dynamics simulation, with consideration of various influential factors including: nanoparticle shape, nanoparticle size, and nanoparticle material. By analyzing number density distribution, radial distribution function, and potentials of mean force the microscopic mechanism in absorption layer is depicted. It is found that the microstructure of absorption layer due to the adding of nanoparticles is entirely different from that of single-phase base fluid. The absorption layer has two denser locations of liquid atoms. The microscopic structure of absorption layer is more ordered and is close to that of solid material. A large energy barrier with a different cis–trans direction of energy barrier is found in potentials of mean force which reveals the mechanism of absorption layer formation. Furthermore, through calculating the mean square displacement and self-diffusion coefficient, the microscopic behavior of liquid atoms is connected to the macroscopic thermal conduction of nanofluids. [ABSTRACT FROM AUTHOR]

• Fine channel mist chemical vapor deposition was used for Cu 2 SnS 3 film preparation. • X-ray diffraction patterns showed the (200), (131), (−131), and (−333) peaks. • Thin film's Raman scattering spectra showed peaks of 292, 313, 353, and 372 cm−1. • The calculated band gap energies of the samples were in the range of 0.89–0.93 eV. • The thin films prepared had the characteristics of monoclinic Cu 2 SnS 3. In this research, rare metal-free Cu 2 SnS 3 (CTS) thin films were fabricated by the fine channel mist chemical vapor deposition (CVD) method, which does not require a vacuum apparatus. The mist solution was prepared by dissolving SnCl 4 and CuCl 2 in pure water (solvent). To obtain Cu-Sn (CT) precursor thin films by the fine channel mist CVD method, the mist solution was sprayed on alkali-free glass (Eagle) substrates heated at 390 °C. The prepared CT precursor films were then heated in a sulfur-containing atmosphere (H 2 S (3%) + N 2) to obtain CTS thin films. The X-ray diffraction patterns of the samples showed the characteristic (200), (131), (−131), and (−333) peaks of monoclinic CTS. Raman scattering spectra of the samples showed peaks in the vicinity of 292, 313, 353, and 372 cm−1, attributed to monoclinic CTS. These results showed that the deposition of monoclinic CTS by the fine channel mist CVD method was prepared. [ABSTRACT FROM AUTHOR]

Abstract: By introducing layer position parameters, we derive analytical expressions for peak absorption efficiencies and layer positions in stacked color sensors, which detect the color information in the depth of the sensor structure. Once the specifications of the color sensors such as the peak wavelengths and the peak absorption efficiencies are determined from system applications, it is expected that the layer structures for the stacked color sensors are easily designed using the derived formulas in this letter. Also, it is shown that the peak absorption efficiencies are determined by only the layer position parameters. [Copyright &y& Elsevier]