Preparation Of High Efficient Electrodes And Their Application In Mesoscopic Solar Cells

Now,new generations of solar cells have entered a rapid period of vigorous development. Mesoscopic solar cell(MSC) has received the widespread attentions for the unique mesoporous structure. Mesoscopic structure possesses larger specific surface area, helping to capture more photon and result in larger photocurrent.Dye-sensitized solar cells(DSSC) are one typical mesoscopic solar cell. Commonly, they employ mosoporous TiO2 nanocrystalline as the photoelectrode. At present, the photoelectric conversional efficiency(PCE) of the mesoscopic solar cell based on mesoporous TiO2 has exceeding 20%, which is comparable to that of the conversional Si version and brings more attention to MSC. What’s more, the fabricating process of MSC is much easier and the cost of materials of MSC is much lower, making MSCs possess larger application potential.In DSSC, metal Pt usually is used as counter electrode materials. Although as a whole the cost of the DSSCs is lower than Si-based solar cells, Pt novel metal is still an issue for further decreasing the price of DSSC. So,on the premise of guarantee the photoelectric conversion efficiency, it will be a critical improvement if the novel mental counter electrode could be replaced by other cheaper materials. Thus, the DSSC will turn into low-cost photovoltaic devices in the real sence.Moreover, for mesoporous electrode, the further optimization of TiO2 and looking for a more ideal mesoporous oxide nanocrystals is also a wide range of ways to further improve the MSC. The mesoscopic perovskite solar cells(MPSC) have beening developed rapidly in recent years and the further optimization of mesoporous electrode has the vital significance for them.In this paper, in order to avoid the disadvantages of the novol mental counter electrode such as high-price and can react with iodine electrolyte, We developed a series high efficiency hybrid counter electrodes based on inorganic compounds and carbon based material, organic polymer(poly(3, 4-ethylene thiophene, PEDOT) and metal or metal oxides. All of them obtained excellent photoelectric conversion efficiency(PCE) and this provides a feasible way to reduce the cost of DSSC provides. Besides, the three-dimensional structure of TiO2 and ternary oxides Zn2SnO4 were employed in MPSC to optimize the mesoporous electrode, providing a new idea to the study of mesoporous electrode.The main content of this thesis include:Firstly, a Molybdenum sulfide/multi-wall carbon nanotube(MoS2/MWCNTs) hybrid was prepared by a lowtemperature hydrothermal method. Owing to the synergistic effects between MWCNTs and MoS2, the MoS2/MWCNTs hybrid shows excellent electrochemical properties. Using the hybrid as CE material for DSSC, which exhibits a comparable photovoltaic performance(7.50%) to the DSSC based on Pt counter electrode(7.49%), the results provide a novel promising Pt-free counter electrode materials for DSSCs.Secondly, PEDOT:PSS with good conductivity and catalytic properties are utilized as the support layer. Through optimizing the H2SO4 concentration and the thickness of PEDOT:PSS layer, the DSSC based the PEDOT:PSS counter electrode can obtain the optimumPCE(7.15%). Binary alloy platinum-cobalt hollow nanospheres and platinum-nickel hollow nanospheres are synthesized by a facile solventbased method at the room temperature. When they were deposit on the PEDOT:PSS layer respectively, the PCE of DSSC were increased. The DSSCs based on Pt-Co and Pt-Ni hollow nanospheres supported with PEDOT:PSS counter electrode achieve power conversion efficiencies of 9.02% and 8.23%, respectively. Under the same conditions, the efficiency for the DSSC based on Pt counter electrode(7.96%) is lower.Thirdiy, a hybrid film consisting of PEDOT and Fe3O4 nanoparticles was prepared via a simple in situ polymerization and was used as the counter electrode for DSSCs. The concentration of Fe3O4 in precursor solution varied from 0 mg·ml-1 to 3 mg·ml-1, the catalytic performance of the hybrid changed. When the concentration of Fe3O4 was 2mg·ml-1(of precursor solution), the hybrid counter electrode has the best electrocatalytic activity. Using the hybrid counter electrode, the DSSC achieved a power conversion efficiency of 8.69%, which is slightly higher than the DSSC based on with Pt counter electrode(8.38%).Fourthly, TiO2 nanosphere with hierarchical structure was prepared instead of traditional TiO2 nanosphere as mesoporous material, the three-dimensional structure of TiO2 is more advantageous to charge directional transmission, and light scattering, received a larger current density, cell efficiency can reach 15.42%. And then, ethanolsolution of NbCl5,isopropyl alcohol solution of n-butyl alcohol Al2O3, alcohol solution of MgO was used to inhibit electronic composite and the open circuit voltage and the fill factor were improved. Lastly, the power conversion efficiency was futher increased to 17.10%.Fifthly, we used a simple hydrothermal synthesis method to prepared Zn2SnO4(ZTO) single crystal and used in MPSC. Grain size of ZTO and morphology of ZTO crystal can been controlled by hydrothermal time. Adding the pore system and spinning to form membrane for MPSC, battery power conversion efficiency was up to 17.01%, especially the short-circuit current density can reach 24.60 mA·cm-2. Put the MPSC in the air and humidity was controlled under 20%. After 15 days, the stability of MPSC were still good, which suggested that ZTO was a kind of very potential mesoporous electron transport materials.