The Preparation Of Organic Solar Cells By Blade Coating Method And The Preparation Of Hole Transport Layer By Solution Method

The field of organic solar cells has witnessed rapid development in recent years.At present,the highest photoelectric conversion efficiency(PCE)of organic solar cells is more than 18%.However,most of the high-efficiency devices of organic solar cells are still in the stage of laboratory preparation.In order to realize the industrialization of organic solar cells,the problem of large area preparation process has to be solved,and the material cost and processing cost of the cell preparation should be considered.Using blade coating method to prepare large area organic solar cells can reduce the waste of materials and simplify the processing process.The main work of this paper is to study the blade coating method to prepare organic solar cells and the solution method to prepare hole transport layer.First of all,the first part of the work is to explore and study the process parameters prepared by blade coating method of organic solar cells.The influence of various parameters on the film thickness and morphology was studied by the control variable method,among which the important parameters were blade slit height,blade coating speed,drying conditions,additive content,etc.The optimal parameters of the blade coating method were as follows:the slit height was 150 um,the blade coating speed was 5 mm/s,the drying conditions were air drying at 25?,and the content of 1,8-diiodoctane(DIO)was 0.25 mg/m L.In this experiment,based on P3HT:O-IDTBR system,the blade coating method was used to obtain0.04 cm2 organic solar cells,and the efficiency reached about 5%.The efficiency of the 1 cm~2organic solar cells prepared by blade coating method could also be maintained at 4.6%,which was very close to the efficiency of the organic solar cells prepared by spinning coating method.It is indicated that the blade coating method has similar effect to the spin coating method in the device fabrication,and it has a great advantage in the large area device fabrication,so the blade coating method is more conducive to the industrial preparation of organic solar cells.The second part of the work focuses on the preparation of large-area organic solar cells by using blade coating method.Base on the PTB7-Th:IEICO-4F system,a four-series organic solar cell module with a photoelectric conversion efficiency of about 4%and the effective area of 16 cm~2 was obtained by dissolving the active layer materials with o-xylene halogen-free solvent.Then,the method of mixing solvent is used to improve the solubility and boiling point of solvent,so as to achieve better blade coating effect.When the volume ratio of o-xylene to tetrahydronaphthalene is 8:2,the film uniformity and morphology of the active layer obtained by blade coating are the best,and the device efficiency is increased to 6.4%.Then we prepared a translucent large area single organic solar cell with an efficiency of 0.5%,a visiblelight transmittance of about 16%,and an effective area of 20 cm~2.In the third part,poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS)prepared by solution method in organic solar cells with inverted device structure,was used as the hole transport layer instead of the molybdenum oxide prepared by vacuum evaporation method with high energy consumption.The modified PEDOT:PSS solution with lower surface tension was obtained by blending PEDOT:PSS aqueous solution with alcohol solvent.Then the PEDOT:PSS was deposited on the active layer by spinning coating method to form a hole transport layer.Based on PM6:BTP-EC9 system,an organic solar cell with photoelectric conversion efficiency of about 13%was obtained.When Ni Ox nanoparticles solution was recoated on PEDOT:PSS layer,the device efficiency increased to more than14%,and when the concentration of Ni Ox nanoparticles solution was 5 mg/m L,the efficient organic solar cell with PCE of 15.50%was obtained.This work provides a new solution method for processing the hole transport layer of organic solar cells with inverted device structure,and provides a technical reserve for the industrialization of full solution processing of organic solar cells in the future.