Toward Aerosol Printing Of Organic Solar Cells Using Environmental-friendly Solvents In Ambient Air

With the surge of power conversion efficiencies(PCEs)of organic solar cells(OSCs)in recent years,OSCs has stepped into the stage of commercial development.In this area,the primary issue is to develop scalable and environmentally friendly device manufacturing technology.Aerosol printing is a non-contact material deposition method that is compatible with flexible or curved substrates for scaled up OSCs fabrication and manufacture.It can also meet the requirement of environmentally friendly by selecting solvents.However,There are few reports about aerosol printing OSCs.Therefore,in this paper,based on a specific vibrating meshes atomization method,the solution is successfully aerosolized,and independently designed an aerosol printing device.Then,we demonstrate the first attempt on fabricating OSC by aerosol printing with the state-of-art OSCs materials of PTQ10:Y6-BO with environmental-friendly solvent of o-xylene in ambient air.Contents are as follows:Firstly,the size of the pores on the VMA surface and the frequency of the piezoelectric ceramics are adjustable.Therefore,under the action of piezoelectric ceramics,droplets with different particle sizes can be obtained by VMA.The experimental results show that when the diameter of VMA is 5 μm,the solution could be atomized into aerosol droplets of ～ 5 μm by VMA.Further,through the self-designed printing device with slit nozzle,the aerosol is printed on the substrate to form thin film.According to the Stokes number and solvent evaporation theory,the gas flow rate at the best material deposition rate is determined,and the corrugated film of different wavelengths is analyzed to calculate the leveling time of the liquid film.Then,the dry film is obtained.Secondly,compared with spin coating method,aerosol printing method has the advantages of high material utilization rate and continuous printing film.Under the optimal parameters of aerosol printing film,the functional layer film was printed and compared with the spin coated functional layer film in morphology and photophysical properties.The experimental results show that the films prepared by aerosol printing have similar macro and micro morphology and similar geophysical properties compared with spin coating.This shows that the aerosol printing method is a supplement to the existing thin film preparation technology.Thirdly,based on the above films,OSC devices were fabricated and their photovoltaic properties were evaluated.The experimental results show that the OSCs with aerosol-printed active layer reaches a PCE up to 15.65%.It may be attributed to the good alignment/crystallization of the thin-film organic molecular materials caused by the printing process.Furthermore,VMA is also suitable for printing hole transport layer and electron transport layer.The OSCs with all aerosol-printed active layer reaches a PCE up to 14.78%,Further,the flexible substrate was replaced by ITO and the flexible OSC device was fabricated by aerosol printing,and the device exhibits PCEs of 12.34%.To illustrate this advantage,a mini automated production line was built to demonstrate the completion of five steps on one conveyer belt,and obtained high-performance OSCs.Aerosol printing is widely used in the fabrication of organic thin films,and it is also an effective method to fabricate high-performance flexible devices.