Study On High-performance Broadband Photodetectors Based On Organic Semiconductor And Perovskite

With the rapid development of electronic technology,the role of optoelectronic products in human society is becoming more and more important,and which is widely used in various fields of social life,industrial production and scientific research.Among them,photodetectors,as one of the members of optoelectronic devices,have made great contributions to the field of optoelectronics,especially the broadband photodetectors playing an important role in various types of photodetection applications.Broadband photodetectors based on traditional inorganic semiconductors have developed quite maturely and become an important pillar of the modern optoelectronics industry.However,inorganic semiconductor-based broadband photodetectors also have disadvantages such as high price,complicated preparation process,high resource consumption,and poor mechanical flexibility,which cannot meet the increasing demands of photodetectors in the new application background.Thus,organic semiconductors and organic-inorganic hybrid perovskites which have advantages of low cost,easy preparation process,abundant material choices,flexible substrate compatibility and so on,have attracted wide attention.Therefore,we have developed a new generation of broadband photodetectors based on organic semiconductors and organic-inorganic hybrid perovskite active materials,and successfully constructed high-performance broadband photodetectors from three directions:Firstly,the photosensitive field-effect transistor has a gate-voltage modulation function which can amplify the optical signal to obtain high photosensitivity,but there are few reports on broadband photosensitive field-effect transistors based on the all-organic active layers.We employed fullerene C₆₀ with high mobility as the channel layer of the photosensitive field-effect transistor,and used a trilayer heterostructure of C₆₀/PTCDA/SnPc with complementary absorption spectrum as the photosensitive layer.After channel optimization,we successfully developed a broadband photosensitive field-effect transistor based on the all-organic active layer.Utilizing the efficient synergy of the channel layer and the photoactive layer,a high-performance ultraviolet-visible-near infrared?UV-Vis-NIR?broadband photodetection is achieved with a high photoresponsivity up to 56.88 A/W and a specific detectivity of 9.15×10¹²Jones in the 300-1000 nm spectral range.Moreover,by replacing the planar heterojunction photosensitive layer with a bulk heterojunction,the photodetection performance of the broadband photosensitive field-effect transistor was further enhanced.Then,the photodiode has the advantages of large light aperture ratio,fast response speed and low driving voltage.Compared with multilayer structure photodiode,the small parasitic capacitance of the double-layer structure photodiode is favorable for the response speed.However,due to the low surface coverage of the organic-inorganic hybrid perovskite film and the large leakage current,it is difficult to construct a double-layer vertical structure perovskite photodiode.We modified the organic-inorganichybridperovskite?MAPbI₃?filmwithpolymer polyvinylpyrrolidone?PVP?,and obtained the best-performance perovskite film by optimizing the concentration of PVP,and combined with the near-infrared sensitive organic semiconductor lead phthalocyanine?PbPc?to form a heterojunction,successfully constructing double-layer vertical structure broadband photodiodes.In the UV-Vis-NIR spectral region,the spectral uniformity factor is as high as 0.77,the photoresponsivity is over 10 A/W,and the response time is less than 0.46 ms.Finally,the photoconductor is a non-polar two-terminal photodetector that can achieve photoconductivity gain with the applied voltage increasing,but it is accompanied by increased noise.We used an organic-inorganic hybrid perovskite MAPbI₃ with UV-Vis absorption and an organic semiconductor tin phthalocyanine?SnPc?with NIR absorption as the active layer materials to construct a lateral structure broadband photoconductor.By optimizing the position of the SnPc layer in the device,the optimal configuration of the device structure is established,and ultra-low pA-scale dark current as low as⁰.01 nA and ultra-high photosensitivity up to¹0⁵ are obtained.Moreover,the device performance was enhanced by the MAPbI₃/SnPc heterostructure,extending the photoresponse to the 980 nm wavelength.Thereby an ultra-highly photosensitive UV-Vis-NIR broadband photoconductor is successfully developed.In short,considering the demands of the development of the times,we focus on the advantages of the new generation of optoelectronic products,exploring the construction of broadband response photodetectors through organic semiconductors and organic-inorganic hybrid perovskites as active layers.We have successfully realized high-performance UV-Vis-NIR ultra-broadband photodetection,paving the way for the development of new photodetectors in the future.