Construction Of Inorganic/Organic Halide Perovskite Dual-band Photodetector And Property Research

Dual-band detector is usually working by using multiple photon-active materials,and it has a special composite structure to achieve the selectiveable detection spectrum which cannot be achieved by a single material.For example,broadening the detection spectrum and dividing the detection spectrum into several spectrums.At present,there are mainly ultraviolet-visible,visible-near-infrared,ultraviolet-infrared,near-infrared to mid-infrared dual-band photodetector.Organic-inorganic hybrid perovskites are widely used in LEDs,solar cells,photodetectors and lasers due to their unique advantages of high light absorption efficiency,high carrier transmission efficiency and long carrier diffusion length.The characteristic of adjustable optical band-gap makes it possible to detect the wide spectrum and narrow spectrum of visible light-infrared light.This paper prepared MAPb I₃film and MAPbBr₃film by using solution method.We studied the morphology,microstructure,and optical properties of the film.Also we fabricated a dual-band photodetector by using MAPb I₃film and MAPbBr₃film as the light absorption layers.Furthemore we has studied the optical detection performance of the device and discussed its dual-band detection mechanism.MAPb I₃ films and MAPbBr₃ films with flat surface,low defect,high density,and high crystallinity were prepared by using the one-step solution method-anti-solvent method,and optimizing the anti-solvent dropping time and perovskite film annealing process.Their microstructures and optical performance were studied.The MAPbBr₃thin-film photodetector and MAPb I₃thin-film photodetector were constructed by using MAPbBr₃photosensitive layer and MAPb I₃photosensitive layer,respectively,which realized the high-efficiency detection of 350-550 nm and 350-800 nm respectively,which have an external quantum efficiency close to 80%,a detectivity of 10¹²Jones high.They have fast response speed to visible light,and the response bandwidth are greater than 250 k Hz respectively.A dual-band detector is proposed with the structure of FTO/Ni O_x/MAPbBr₃/PCBM/Ti O₂/MAPb I₃/P3HT/Ag,which have a structrue of two photodiode stacking devices with opposite polarities based on MAPbBr₃and MAPb I₃films,and we revealed that under different spectrum of visible light detection mechanism.By optimizing the relative thickness of the MAPbBr₃film and the MAPb I₃film,the wavelengths of 350-550 nm and 550-800 nm respectively can be detected under different positive and negative bias voltages.By controlling the direction and magnitude of the applied bias voltage,the response of a single device can be switchable between 300-570 nm and 630-800 nm.The optical crosstalk of the device is less than-10 d B,and some specific bands are less than-30 d B.The switching ratio of the dual-band detector is about 10⁸,the response bandwidth(f_{-3d B})is about 33 KHz,the response switching rate is close to 1000 Hz,and the detectivity is 1.75×10¹⁰Jones,which makes it has a very good performace in encryption of visible light communication.The application prospects ensure its application as an efficient data receiver.In the solution synthesis of organic-inorganic hybrid perovskite,a quasi-two-dimensional PEA₂MA₄Pb₅I₁₆film was prepared by adding PEAI,NH₄SCN and NH₄Br.It is found that when NH₄SCN and NH₄Br was added,they improved the crystallization performance and surface flatness of the perovskite polycrystalline film,and promoted PEA₂MA₄Pb₅I₁₆film growth along the（202）crystal plane direction,and they increaseed the anisotropy,and realizes the full range of visible light from 400-800 nm polarization detection,the degree of polarization at 610 nm is 0.26,the response bandwidth is up to 210 KHz,and the detectivity is up to 10⁹ Jones.