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In this paper, the compact and ultra-thin CdS thin films with different spin cycles are deposited on the TiO2 nanorod arrays via spin-coated-assisted successive ionic layer adsorption and reaction method using Cd(NO3)2 solution in methanol and the Na2S solution in methanol/water (v/v, 95/5), and the Sb2S3 prepared by pyrolysis using SbCl3-thiourea complex solution in DMF. In the Sb2S3-sensitized solar cells, the compact and ultra-thin CdS thin films with suitable band gap and higher electron mobility can suppress the charge recombination, the electrons of the TiO2 conduction band, and the holes of the spiro-OMeTAD valence band, and it can also transport photogenerated electrons rapidly from Sb2S3 to TiO2. The thickness and microstructure of the CdS buffer layers can be adjusted by spin cycles and the influence of the thickness and microstructure of the CdS buffer layers on the photovoltaic property of the corresponding solar cell was systematically investigated. The Sb2S3-sensitized solar cells with 5 layers CdS thin film achieved the best photovoltaic conversion efficiency (PCE) of 5.71% along with the open-circuit voltage (Voc) of 0.53 V, short-circuit photocurrent density (Jsc) of 18.20 mA cm−2, fill factor (FF) of 58.99%, and the average PCE of 5.59 ± 0.08% with the Voc of 0.53 ± 0.01 V, Jsc of 17.72 ± 0.43 mA cm−2, and FF of 59.05 ± 0.65%. [ABSTRACT FROM AUTHOR]

The porous Sb2SxSe3-x thin films with different pore sizes were successfully prepared on the TiO2 compact layer by the pyrolysis of the precursor solution containing N-butyldithiocarbamic acid, Se, and Sb2O3 in DMF and using the relative low spin-coating speed. The effect of the pyrolysis temperature on the chemical composition, optical absorption, crystal phase, and pore size of the porous Sb2SxSe3-x thin films was investigated, and the corresponding solar cells were also fabricated. The results points out that the Sb2SxSe3-x thin film pore sizes decreased with the increase of the pyrolysis temperature from 360 to 440 °C. The porous Sb2SxSe3-x thin films provided a possible path for assembling the hybrid absorption layer with quantum dots. [ABSTRACT FROM AUTHOR]

In this paper, the ultra-thin and high-quality WO 3 compact layers were successfully prepared by spin-coating-pyrolysis method using the tungsten isopropoxide solution in isopropanol. The influence of WO 3 and TiO 2 compact layer thickness on the photovoltaic performance of planar perovskite solar cells was systematically compared, and the interface charge transfer and recombination in planar perovskite solar cells with TiO 2 compact layer was analyzed by electrochemical impedance spectroscopy. The results revealed that the optimum thickness of WO 3 and TiO 2 compact layer was 15 nm and 60 nm. The planar perovskite solar cell with 15 nm WO 3 compact layer gave a 9.69% average and 10.14% maximum photoelectric conversion efficiency, whereas the planar perovskite solar cell with 60 nm TiO 2 compact layer achieved a 11.79% average and 12.64% maximum photoelectric conversion efficiency. [ABSTRACT FROM AUTHOR]

Abstract: The Cu2ZnSnS4 (CZTS) thin films with uniform and porous surface feature with the pore size of 100-200nm were successfully prepared by pyrolysis procedure using the methanol solution containing copper chloride dihydrate (0.06mol dm−3), zinc chloride (0.03mol dm−3), stannous chloride dihydrate (0.03mol dm−3), thiourea (0.48mol dm−3) and deionized water (1.92mol dm−3) as precursor solution at 380°C in air atmosphere. Electrochemical impedance spectroscopy was applied to evaluate the electrochemical catalytic activity of the pyrolysis CZTS thin films for redox couple of Sn 2-/S2− and the charge transfer resistance was 64.08Ω using the pyrolysis CZTS thin film obtained by repeating the procedure of dipping the FTO substrate into the precursor solution and heating at 380°C for 7 cycles. The assembled quantum dot-sensitized solar cells gave an open-circuit photovoltage of 0.52V, a short-circuit photocurrent density of 12.96mAcm−2, and a fill factor of 0.38, corresponding to the photoelectric conversion efficiency of 2.56%. Because the pyrolysis procedure was a facile, low cost and vacuum-free process, and had the advantage of obtaining various porous microstructure thin films and allowing deposition over large areas, the pyrolysis CZTS thin films can serve as an effective counter electrode for QDSCs. [Copyright &y& Elsevier]