| Due to high sensitivity,fast response,and broad spectral response,silicon photodiodes have been widely used as sensors in mobile electronic,security,medical testing and smart home equipment,and are also expected to be applied to flexible fields.However,the crystallization process is complex and the single crystal structure is difficult to fabricate as flexible devices which have attracted attention.The materials applied on flexible devices need to undergo ten thousands of bending without performance loss.Flexible substrate materials with thermal and mechanical stability are also needed to meet the manufacturing process of flexible photodiodes.In this work,polyimide(PI)is used as flexible substrate material and the preparation process of polyimide films was investigated.Also,PCDTBT and organic-inorganic hybrid perovskite photodiodes were fabricated on the polyimide substrates and the performance of the hole transport layer was investigated.The main contents are as follows:(1)Polyimide films were prepared and thermal stability as well as mechanical performance were investigated.The effects of annealing atmosphere,film thickness,and slurry storage time on the mechanical properties of the polyimide substrates were also investigated.Finally,the thermal weight loss performance was investigated.(2)Indium tin oxide(ITO)was prepared on the flexible polyimide substrates as transparent electrodes,and the PCDTBT photodiodes were fabricated.The concentration effect of CCO nanoparticles on the hole transporting performance of CCO doped PEDOT:PSS was investigated.The composite layers of CCO doped PEDOT:PSS have a larger surface area,which decreases the contact resistance.And the dark current of the device tested under-3V is reduced from 2.20×10-7 to 1.51×10-7 A·cm-2.The experiment also proves that the PCDTBT photodiodes have high reliability after 50,000 bending cycles.(3)The perovskite photodiodes with the structure of ITO/PTAA/Perovskite/PCBM/Ag were fabricated on the ITO/polyimide substrates.The effect of ZnO layer between PTAA and ITO layers on the crystallization of perovskite and the performance of photodiodes.The results show that the dark current of the device is reduced from 2.04×10-8 to 1.71×10-9 A·cm-2 due to inserting the ZnO layer.The detectivity is 6.19×1012 Jones,and the perovskite photodiodes have high reliability after 5000 bending cycles. |
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