Surface Plasmon Enhancement In The Application Of Graphene Based New Type Solar Cell

Since the bloom of economy and the exhausted of traditional energy, developing new energy is paid more attention. As a potential clean energy, solar power is considered a top candidate to replace traditional energy. Unlike the traditional Si-based solar cells, dye-sensitized solar cells have attracted broad attentions for their simpler procession, lower cost and less pollution. But there are some bottlenecks for the commercial application. First, it contain liquid which will shorter the life time, raising the cost and making the battery more unstable and unsafe. Second, transparency electrode like ITO and FTO is expensive and not suitable for flexibility photovoltaic device. Third, the diffusion length of excitons in traditional dye-sensitized solar cells is much shorter than the thickness of dye molecule, and the mobility in dye-sensitized solar is lower than Si-based solar cells, which requires a thinner active layer to gain higher efficiency. But a thinner active layer will cause less absorption of light to suppress the efficiency.Based on the precondition of dye-sensitized solar cells, this article mainly focuses on improving the incident photo to electron conversion efficiency (IPCE) of solar cells. Plasma resonance enhanced mechanism of metal nanoparticles and the high mobility and transparent of graphene were used to fabricate a newly solid solar cells. Meantime, I have simulated the mode of solar cells with FDTD to research the transport on the interlayer of charge and energy. The main content mainly has three parts.1) Because of the advantages of graphene like transparent and high mobility, I have used graphene as both the HTM and electrode to replace electrolyte solution and electrode. With the arrangement of back electrodes, wide bandgap semiconductor, dye sensitized molecules, graphene and metal nanoparticles, several novel solid dye-sensitized solar cells were fabricated. Selecting the Z907 as the light-absorbing molecule like traditional dye-sensitized solar cells, using single crystal TiO2 as semiconductor, evaporating a layer of In-Ag alloy as back electrolyte and evaporating 8 nm Au-Ag alloy nanoparticles as plasma were utilized to improve the IPCE of solar cells.Analyzing the IPCE with different metals and the physical characterizations, the reason that affect the changing of performance of solar cells was revealed. Meantime, the physics mode built with FDTD theory was utilized to analyze the plasma resonance enhancement from metal nanoparticles, and the energy aggregation on the interface of graphene, stimulate dye molecule that absorbing on the surface of TiO2, improve the IPCE of solar cells, and enrich the mechanism of the newly solid dye-sensitized soar cells.2) Depositing different thickness alloy layer by alternate evaporating metal and then annealing to form nanoparticles with different sizes was utilized to compare the IPCE of the solar cell with different thickness alloy layer and analyze the effect caused by nanoparticles. With the help of SEM, we can get the relation of thickness and spatial distribution of particles, and apply it on FDTD to build modes with different particle sizes. So we can get the influence of the size of nanoparticles on the energy distribution of the interlayer between graphene and TiO2. Then we can get the mechanism of the spatial distribution of particles on the performance of solar cells.3) Through using the Ado molecule as the light-absorbing dye and evaporating corresponding Ag nanoparticles with Ado molecule on them, ternary interlayer of Ado+NPs/Gr/TiO2 form a new solar cell device based on the mechanism of selective tunneling was constructed. When compared the performance of solar cells with and without Ag nanoparticles, it turns out that plasma resonance enhancement from metal nanoparticles can stimulate Ado molecules around it, and then improve the IPCE. Because the Ado molecule is assembled on the outermost shell, I have research the influence of the thickness of Ado molecule layer. Combining with the charge and energy transport theory on the ternary interlayer was utilized to explain the physical mechanism, and building the ternary interlayer mode of Ado+NPs/Gr/TiO2 with FDTD was utilized to analyze the influence of thickness on the performance of solar cells.