Application Of Conductive Porous Carbon Materials In The Counter Electrode Of Advanced Solar Cells

The development and application of solar cells is an effective way to solve energy crisis and environmental problems.Perovskite Solar Cells（PSCs）and Dye-Sensitized Solar Cells（DSSCs）,which have many advantages such as high theoretical Photoelectric Conversion Efficiency（PCE）and simple manufacturing process,are typical representatives of the third generation of advanced solar cells,and have received extensive attention from researchers around the world.However,these new types of solar cells still have some problems,such as poor stability,high production costs and unclear transmission mechanism,so that they cannot achieve practical inductrial application up to now.For these deficiencies,this paper uses a porous metal/carbon composite material with excellent conductivity,treated with a simple grinding process to replace the Hole Transport Layer（HTL）in PSCs and Au Counter Electrode（CE）in DSSCs,respectively.（1）Study on interface modification of carbon electrode of PSCs by grinding process and its capacitor model:This chapter uses a new solvent replacement method to treat commercially available conductive carbon pastes to obtain porous conductive carbon particles,which can be easily dispersed in chlorobenzene.The prepared carbon electrode is used to replace the conventional HTL and the noble metal CE in PSCs,combining the perovskite layer and the TiO₂ Electron Transport Layer,a PCE of up to 9.04%is obtained.Through SEM characterization,it is found that there are some hole defects between the carbon layer and the perovskite layer,which is not conducive to carrier transport.In order to reduce this defect,the surface of the carbon electrode is treated by a grinding process.With SEM,AFM and EIS characterizations,it is found that the grinding process effectively reduces the defects at the interface between the carbon electrode and the perovskite layer,reduces the series resistance of the device,effectively improves the interface quality,and the optimal efficiency of the cell is upgraded to 10.11%.Based on the delayed open circuit photovoltage technology,a capacitor mechanism in PSCs is propased and the hysteresis of PSCss is well explained.（2）Preparation of Co-Ni/carbon aerogel and its application in PSCs:The Co-Ni bimetallic ions are dispersed in the organic framework by complexation of metal ions with organic matter,and their spatial structure is maintained after freeze-drying and carbonization process.Using it instead of the conventional HTL and the CE in the PSCs,combining with the grinding process,the interfacial properties between the carbon layer and the perovskite layer were effectively improved.The morphology and structure of the composite aerogel were analyzed by SEM,Mapping,TEM,XRD and BET.The photoelectric properties of the cells were tested by J-V curve and EIS.The results show that the Co-Ni/carbon composite CE effectively fills the interface defects and improves the extraction efficiency of holes by the grinding process.The efficiency of the Co-Ni/carbon composite as the electrode was increased to 10.05%,and the efficiency was increased to 12.05%after the grinding process.At the same time,the Chronoamperometry method under illumination conditions was used to study the charge and discharge phenomenon of the battery,which proved the connection between the capacitor effect and the hysteresis.Due to the protective effect of the aerogel on the perovskite layer,the whole device has long time stability.After 1296 h,the battery still maintained an efficiency of 86%relative to the initial value.（3）Application of Co-Ni/carbon aerogel in DSSCs:Because Co-Ni/carbon aerogel material has a large specific surface area,a large number of catalytically active sites and good catalytic activity,which is very suitable for preparing the dye-sensitized solar cell CE instead of the traditional CE Pt.Co-Ni/carbon aerogel was used as a CE,ZnO sensitized with N719 dye was used as a photoanode,and I^-/I₃^-redox couple was used as an electrolyte.The morphology and structure of the composite aerogel were analyzed by SEM,Mapping,TEM and XRD.The effects of different metal ratios on the performance of the electrodes were investigated using J-V curves,EIS and C-V curves.Finally,a PCE of 5.08%was obtained,and the efficiency of the corresponding Pt-based cell was 5.35%,and the efficiency reached 94.44%of the efficiency of the Pt-based cell.