CH₃NH₃PbI₃ Flexible Composite Films And Their Photosensitive Devices

The Organic-inorganic hybrid halide perovskite material with CH3NH3PbI3 as a typical representative has been developed into a 23.3%photoelectric conversion efficiency in just a few years,since it was first introduced into solar cells.Perovskites have attracted a huge amount of research interest and raised new research upsurge due to its broad absorption range,low trap density,low carrier recombination and other excellent optoelectronic properties.With the development of perovskite solar cells,the problem of CH3NH3PbI3 perovskite is gradually exposed such as poor flexibility,which is not suitable for the preparation of flexible devices with wider application.In the context of the emergence of the concept of "wearable",traditional perovskite optoelectronic devices cannot be truly promoted and put into use without solving the problem of flexibility.This paper attempts to prepare the flexible composite film of CH3NH3PbI3,PAN/CH3NH3PbI3 composite fiber film and CH3NH3PbI3/BOPP flexible composite film,by electrospinning and vacuum evaporation.The PAN/CH3NH3PbI3 composite fiber was prepared to improve the flexibility of the material.Several composite fibers with different contents of CH3NH3PbI3 were prepared and the photodetectors were fabricated based on this composite fiber film.The content of CH3NH3PbI3 in fibers increased from 66.6wt%to 85.7wt%.With the increase of perovskite content,the light response current increased.When the voltage bias is 10V and the wavelength is 700nm,the intensity of photoresponse can reach 6.5?A W-1.Based on its high sensitivity,the photodetector also has a good response to weak light sources such as laser pointers.Because of the protection of PAN,the device stability and material stability have also been greatly improved,and the better light detection effect can be maintained after 100 hours in the air.A flexible photoelectric detector is constructed by using PAN/CH3NH3PbI3 composite fiber film.The photocurrent of the device decreases with the increase of bending degree.Therefore,the flexible device can be used as a flexible wearable device by sensing action.Secondly,the CH3NH3PbI3/BOPP flexible composite film prepared by vacuum evaporation not only maintains the excellent photoelectric properties of CH3NH3PbI3,but also has the good flexibility of BOPP film.It is an ideal material for preparing CH3NH3PbI3 flexible photovoltaic devices.We fabricated photodetectors based on this composite film showing remarkable photoresponse.It is found that the proper amount of PbI2 produced during the natural decomposition of CH3NH3PbI3 can promote effective charge transfer,and thus improve the photocurrent response and the carrier utilization rate.The photocurrent of the detector reaches its peak after 36 hours of natural decomposition in air,which improves the stability of CH3NH3PbI3 materials and devices to a certain extent.The flexible detector based on this composite film also exhibits good optical detection performance.With the increase of bending degree,the dynamic current and static current both show a decreasing trend.