Fabrication And Performance Study Of PTB7 Based Optoelectronic Device

Organic solar cells and organic infrared photodetector have attracted wide attentions due to their advantages of low cost,easy to large-scale production and the small environmental pollution.Performance of organic solar cells and organic infrared photodetector have been improved by the synthesis of new polymers and the design of various device structure.However,the power conversion efficiency(PCE)and the stability of organic solar cells are not very high compared with Si-based solar cells.Also,organic infrared photodetector have the disadvantages of low photoresponsivity and photodetectivity.Our work contains two sections: 1)Organic solvents with different polarity were utilized to treat PEDOT:PSS for enhancing its conductivity.Organic solar cells with treated-PEDOT:PSS were fabricated.2)Organic infrared photodetector with an active layer of PTB7:CNT:PCBM was fabricated.Photo-generated dipoles in PTB7 was utilized to promote exciton dissociation.Consequently,photoresponsivity and photodetectivity was enhanced.This paper mainly study the followings:1.PEDOT:PSS was treated by 6 high polarity organic solvent,DMF,DMSO,formamide,methanol,ethanol,IPA.Mechanism on how solvent with different polarity affect the conductivity of PEDOT:PSS was studied.2.Organic solar cells with structure of ITO/PEDOT:PSS(DMSO treatment)/PTB7:PCBM/Zn O/Al was fabricated considering that DMSO enhance the conductivity of PEDOT:PSS the most.Doping ratio of DMSO was optimized.Ultimately,a PCE of 6.5% was obtained.Air stability of the device was promoted.3.organic infrared photodetector with a structure of ITO/PEDOT:PSS/PTB7:CNT:PCBM/ZnO/Al was fabricated.We have optimized the performance of the devices by changing the concentration of active layer and the doping ratio of carbon nanotube.A high photodetectivity of 2.3×1011 Jones at 1100 nm was obtained.4.ITO/PEDOT:PSS/P3HT:CNT:PCBM/ZnO/Al device was fabricated to prove that photo generated dipoles could enhance the build-in electric field.Therefore,exciton dissociation was enhanced.Moreover,exciton dissociation was proportional to the amount of dipoles.