Performance Optimization Of Si/PEDOT:PSS Hybrid Solar Cells

With the adjustment of energy structure and the requirement of sustainable development increasing,it is extremely urgent to develop clean energy.Solar cells become one of options due to their environmentally friendly characteristic.In all kinds of solar cells,organic/inorganic hybrid solar cells not only take advantage of the high stability,high carrier mobility and mature preparation technology of inorganic materials,but also utilize the plasticity of molecular structure,the adjustment of spectral absorption and the simple solution preparation process of organic materials.Thus,the purpose of preparing low cost and high efficiency solar cells can be achieved.In order to prepare high efficiency organic/inorganic hybrid solar cells,the silicon/PEDOT:PSS hybrid solar cells are fabricated by using n-type silicon and conductive polymer PEDOT:PSS(poly(3,4-ethylenedioxythiophene):poly(stylenesulfonate)).In order to optimize the performance of Si/PEDOT:PSS hybrid solar cells,through etching micro-nanostructure on silicon surface and introducing carbon quantum dots(CQDs),the device and the interface between silicon and PEDOT:PSS is modified.The main research contents are as follows:(1)The research background and current status of silicon/PEDOT:PSS hybrid solar cells are briefly introduced.The working principle and preparation methods of silicon/PEDOT:PSS hybrid solar cells are summarized.The research purpose,research content,testing and characterization methods of this thesis are described.(2)The effects of the concentration of dimethyl sulfoxide(DMSO)and the film thickness of PEDOT:PSS on device performance are studied.It is found that when the optimal concentration of dimethyl sulfoxide is 5 wt.%and the ideal speed of spin coating is 3500 rpm/min,namely the film thickness of PEDOT:PSS is about 80 nm,the power conversion efficiency of 9.2%is achieved.(3)Carbon quantum dots prepared by microwave-assisted method are introduced at the interface between silicon and PEDOT:PSS,and the effect of CQDs on the performance of Si/PEDOT:PSS hybrid solar cells is studied.It is indicated that the series resistance of the device with saturated carbon quantum dots solution decreases from 4.21?·cm~2 to 3.50?·cm~2,the open-circuit voltage increases from 0.540 V to 0.615 V,and the filling factor increases from 59.6%to62.5%.The power conversion efficiency of the prepared Ga:In/Si/CQDs/PEDOT:PSS/Ag hybrid solar cell reaches 11.5%.(4)In order to improve the short-circuit current density of planar silicon hybrid solar cells,the trapping effect on sunshine was enhanced by fabricating micro-nanostructures on the surface of silicon wafers.Using the anisotropic etching of silicon in alkaline solution,the pyramid structure is obtained by etching the silicon wafer in 5 wt.%KOH solution.And after the secondary etching,surface of the pyramid structure is reconstructed,and the micro-nanostructure with low aspect ratio is obtained.It can exhibit excellent light trapping properties and favorable conformal coating.The experimental results show that the short-circuit current density of silicon micro-nanostructure/PEDOT:PSS hybrid solar cell increases from 28.68 mA/cm~2 to 31.28 mA/cm~2,and the filling factor does not reduce compared with the planar silicon/PEDOT:PSS hybrid solar cells,indicating that the contact quality between micro-nanostructure and PEDOT:PSS is well.The reconstructed micro-nanostructure can not only improve the short circuit current density,but also ensure the quality of heterojunction.(5)The main research contents and related results are summarized,and the future development of Si/PEDOT:PSS hybrid solar cells is prospected.