Growth Control Of Silver Electrode Via Surface Tuning And Its Application In Organic Solar Cells

The electrode is an important part of organic solar cells,which directly affect the performance of the device.This thesis focuses on optimizing the growth mode of Ag electrode via surface tuning to obtain the Ag electrode with high conductivity,high transparency,and low surface roughness.The main results are as follows:First,a new strategy using a reducing material,hydrogen molybdenum bronze(H_xMoO₃),as the growth surface of Ag films is proposed.The chemical interactions between H_xMoO₃and silver oxide increase the nucleation sites during the early stage of the growth of Ag and assist the continuous and uniform growth of the Ag films.As a consequence,the percolation threshold thickness of Ag on H_xMoO₃ is reduced to 4 nm with a sheet resistance of 19?sq^-1.Second,the ultrathin Ag electrode is optimized by optical simulation based on the transfer matrix method.After introducing the antireflection layer and optimizing its thickness,the average transmittance of the ultrathin Ag electrode increases while its electrical property is maintained.Following the optimum results of the optical simulation,we fabricated the rigid and flexible organic solar cells,which using ultrathin Ag electrode as transparent electrode,with efficiency of 12.75%and 12.04%,respectively.Third,the 70-nm thick Ag electrode on H_xMoO₃ with a low surface roughness of 1.06nm is obtained based on the characteristic,improving the growth of Ag,of H_xMoO₃.Furthermore,the 10 cm² top-illuminated large-area organic solar cell with an efficiency of10.24%is fabricated successfully using such smooth 70-nm thick Ag as the bottom electrode and ultrathin Ag as the top electrode.Meanwhile,the yield of large-area devices is significantly enhanced compared to that on ITO.