A Two-dimensional Sheet Matrix Composites To Build A Controllable Electrodes And Photoelectric Properties

Dye-sensitized solar cells (DSSC) attract much attention because of the low-cost,easy fabrication and high energy conversion efficiency. A DSSC is made up ofphotoanode, dye sensitzers, redox electrolytes and counter electrode. In terms of thematerial for the counter electrode, it should not only combine high efficient energyconversion and high stability, but it possesses low cost as well. In this paper, a series ofcomposite counter electrodes (carbon material/carbon material, carbon material/transition-metal sulfide, transition-metal sulfide/transition-metal sulfide) werefabricated based on carbon material and transition-metal sulfide. And the relationshipbetween the experimental parameters (e.g. ratio of the raw material, film’s fabricationmethod) and the energy conversion efficiency, catalytic activity of the DSSCs weresystematically studied. The main contents of this paper are as follows:1) The highly-crystallinity graphene/carbon black composite counter electrodeswere fabricated with the mechanical blending, and by controlling the different ratios ofthe graphene to carbon black, the conversion efficiencies of the DSSCs withcomposite-based counter electrodes were researched as well. When the weight ratio ofthe grahene was25%, the DSSC achieved the highest conversion efficiency among thePt-free counter electrode-based DSSCs (5.99%). It was because that the compositecounter electrode held the advantages of rapid electron transport fromhighly-crystallinity graphene and more catalytic activity sites from low-crystallinitycarbon black.2) Well-dispersed graphene nanosheet/CoS composite counter electrode werefabricate with electrophoretic deposition and the conversion efficiency of the DSSCbased on the above composite counter electrode was5.54%, much higher than that ofthe DSSCs with pure graphene nanosheet counter electrode and pure CoS counter electrode. In addition, the conversion efficiency for composite counter electrode withelectrophoretic deposition outnumbered the counterpart fabricated with successiveionic layer absorption reaction, which was attributed to the well-dispersion of the CoSon the surface of the graphene nanosheet and enabled the composite counter electrodeto possess high electron transport and efficient catalytic activity.3) The MoS2/CoS composite were synthesize with a facile hydrothermal method,followed by fabricating the composite counter electrode with sprayed method.Compared with the DSSCs resulting from pure MoS2-based counter electrode and pureCoS-based counter electrode, the DSSC fabricated with the composite counterelectrode experienced higher conversion efficiency. The MoS2in the composite playeda role in restraining the agglomeration of the CoS nanoparticles, improving thecatalytic activity sites in the composite counter electrode.