Study Of Photodetectors Based On Perovskite Materials

Photodetectors are widely used in emerging fields such as medical imaging,military surveillance,optical communications,and surveillance camera systems as the devices that convert light signal（ultraviolet light,visible light or infrared light）into electrical signal.So far,many types of semiconductor optoelectronic materials have been used to fabricate high-performance photodetectors,such as silicon,III-V composite semiconductors,colloidal quantum dots,or organic materials.However,the photodetectors based on the above materials are severely limited in application due to their complicated manufacturing process,high cost,and incomplete material properties.In recent years,organic-inorganic hybrid perovskite（OIHP）materials have excellent physical and chemical properties due to their large optical absorption coefficient,adjustable band gap,long exciton diffusion length,and high carrier mobility,which has been comparable to traditional materials.Perovskite-based solar cells,light-emitting diodes,and photodetectors are all important research fields.In this paper,perovskite related performance parameters and manufacturing process are introduced,and we have carried out three aspects of research in the field of photodetectors to solve some problems in the field of detectors.First of all,the surface and grain boundaries of solution-processed perovskite polycrystalline films often have a large number of defects,which will seriously affect the performance perovskite photodetectors.In order to deal with this problem and make high-performance perovskite photodetectors,we use a non-fullerene passivation layer to efficiently passivate the perovskite surface,greatly reducing the density of trap states.At-0.1v the dark current is as low as 2.6×10^-8 A cm^-2,in addition,the strong absorption of the non-fullerene IEICO composite C₆₀ heterojunction in the near-infrared（NIR）region extends the detection range to more than 900 nm through effective charge transport,and finally the detectivity（D*）at 650 nm and 820 nm reach 1.45×10¹² cm Hz¹/2/2 W^-1 and 7.37×10¹¹ cm Hz^1/2 W^-1.With a device area of 0.6 mm²,the device achieves an ultra-fast response time of 27 ns after reducing the resistance-capacitance time constant.In addition,this detector was successfully used in low-light detection circuits and visible light communication systems in this study,showing its practical application valueIn addition,the strong absorption of the non-fullerene composite C₆₀heterojunction in the near-infrared region extends the detection range to more than 900nm through effective charge transport,and finally the detection at 650 nm and 820 nm reaches 1.45×10¹² cm Hz^1/2 W^-1and 7.37×10¹¹ cm Hz^1/2 W^-1,respectively.With the small device area of 0.6 mm²,the photodetector achieves an ultra-fast response time of27 ns after reducing the resistance-capacitance（RC）time constant.Besides,it has been successfully used in a weak light detection circuit and visible light communication system in this study,showing its practical application value.Second,OIHP photodetectors used in imaging applications need to be further improved its performance.The perovskite-based photodetectors have good photoelectric characteristics such as fast response,low noise,but the research that photodetectors both with high EQE in the near infrared region and ultra-fast response speed has not been reported yet.This research proposes a broadband photodetector based on perovskite and organic bulk heterojunction,which has an EQE of 54%in NIR region and a fastest response speed of 5.6 ns.In addition,more than simply characterizing performance parameters,it is more valuable to introduce the device into practical applications.This photodetector exhibits an outstanding high dynamic range imaging capability and achieves visible-NIR high-quality imaging,providing a great possibility for market application.Finally,in order to further improve the performance of the perovskite photodetectors,we replaced the main material with a perovskite thin single crystal,which is different from the above mentioned polycrystalline thin film as the active layer.Because the single crystal surface is smooth,no grain boundaries and no void,resulting in the characteristics of higher carrier mobility and lower trap density.The result shows that the D*of single crystal thin film photodetectors is as high as 1×10¹² cm Hz^1/2 W^-1or more in the detectable wavelength range.At the same time,single crystal photodetectors have large linear dynamic range up to 207 dB,and a response speed of51 ns,which is far ahead of the performance parameter level with other single crystal perovskite photodetectors.We use a single crystal photodetector as the optical signal receiver to complete the work of the visible light communication system at 5 MHz,which also shows its practical application value.This paper has introduced the performance parameters and manufacturing processes of OIHP photodetectors in detail,and solves many problems in the field of detectors from multiple aspects,improving related performance.This content will have high inspiration and commercial value in the related areas.