Preparation, Optimization And Mechanism Of Polymer Photovoltaic Devices And Carbon Aerogel Counter Electrode

The recent improvements of bulk heterojunction (BHJ) polymer solar cells (PSCs) and dye-sensitized solar cells (DSSCs) were briefly introduced in the dissertation. As we all know, the phase separation morphology of the photoactive layer is a critical factor in determining the solar-to-electric efficiency of BHJ PSCs. Therefore, the effect of the interface modifiers of the photoactive layer on the photovoltaic properties was investigated in this paper. Carbon aerogel is a favorable catalyst candidate for counter electrode of DSSC because of the unique features such as low cost, high performance and flexible properties. The different mesoporous carbon aerogel were prepared, and the effects of the pore structure of carbon aerogel on the catalytic activity of carbon aerogel counter electrodes were discussed. On the same time, the effects of the activation and carrying silver of carbon aerogel on the catalytic activity were investigated. The main study results are as follows:1.PSCs devices were fabricated and optimized with a polyfluorene derivative with electron-withdrawing oxadiazole (OXD)side chain as electron donor, the fullerene derivertives PCBM as acceptor,1,8-diiodooctane or methyl 4-(octyloxy)benzoate as the interfacial modifier. Then the effects of the varied ratio of modifier/donor on the microphase separation structure and the photovoltaic performance of PSCs were investigated. The results indicate that the addition of 1,8-diiodooctane is not benefited for the photovoltaic performance of the PSCs. When the ratio of methyl 4-(octyloxy) benzoate /donor is 5%, the PCE of the PSCs is improved from 1.45% to 1.93% because the interfacial modifier improves the interpenetrating polymer network structure of the photoactive layer. However, the photovoltaic performance of the PSCs would reduce in case methyl 4-(octyloxy)benzoate is excessive because of the destroy of the interpenetrating polymer network structure.2. Six kinds of carbon aerogels with different pore structure were prepared. With the increasing mesopore volume of the carbon aerogel, the charge transfer resistance on the carbon aerogel counter electrodes electrochemical impedance reduces, and the catalytic reduction activity of the carbon aerogel counter electrode enhances. The power conversion efficiency of DSSCs based on CA3-1 counter electrode achieves 99% of the efficiency of the DSSC based on Pt counter electrode under the same condition. After activated by potassium hydroxide acetone solution, the mesopore volume of activated carbon aerogel increases, and the catalytic activity of the carbon aerogel counter electrode improves. 3. Silver-loaded carbon aerogels were prepared by carbonising the organic aerogel absorbing AgNO3. The mesopore volume of the silver-loaded carbon aerogels reduce with respect to the carbon aerogel. The short-circuit photocurrents of the DSSCs based on silver-loaded carbon aerogel counter electrode rapidly increase with increasing illumination time. After 10 min illumination, the short-circuit photocurrents of the DSSCs achieve the maximum values, and the power conversion efficiencies exceed that of the DSSCs based on Pt counter electrode, which would be explained that a electrochemical reaction based on silver is formed in the DSSCs.