No abstract

A ternary mixture of carbon, copper sulfide, and cobalt sulfide was used to fabricate the counter electrode (CE) in quantum-dot-sensitized solar cells (QDSSCs). The ternary-mixture-based CE achieved much higher energy conversion efficiency than any CE based on the individual material. The mixture and the CE were investigated by photocurrent density–voltage characteristics, X-ray diffraction patterns, electrochemical impedance spectroscopy, and contour line plots. A balanced mix results in enhanced photocurrent and reduced charge transfer resistance at the interface, and this leads to optimized device performance. The highest photoelectric conversion efficiency was 3.73% at a 1:1:1 mass ratio. The efficiency was as high as 3.09% via a corresponding flexible CE.

In order to improve the ablation resistance of C/C composites, an AlSiB alloy (mass ratio of Al/Si/B = 2:4:1) was used as a dissipative agent to fill the pores of a C/C composites matrix by reactive melt infiltration to prepare AlSiB-C/C composites. The microstructure evolution and ablation behavior of the obtained AlSiB-C/C composites (mass ratio of Al/Si/B = 2:4:1) under oxy-acetylene flame were investigated by SEM after ablating for 25 s, 50 s, 100 s and 150 s. At the beginning of the ablation process, thermal chemical erosion played a leading part. By using the heat-absorption effect of sweating and the sealing protection effect of the oxide layer, AlSiB-C/C composites significantly reduced the ablation surface temperature, and the linear ablation rate was 4.04 μm/s. With the process of ablation, thermal mechanical erosion tended to dominate. The specimen surface could not form a continuous covering of oxide film to slow down the flame scour, resulting in non-uniform ablation and further expansion of the ablation pit. The self-transpiration cooling behavior and the self-sealing of the ablation products of the dissipative agent played an important role in reducing the extent of thermal chemical erosion and preventing matrix ablation.