| Polarized photodetectors can not only distinguish the radiation intensity between the target and the background,but also identify the polarization information of the target.The polarized photodetector can effectively suppress the interference signal and improve the target contrast.Therefore,it has a good prospect for civilian and military application.Polarization detection can be realized by using anisotropic light-absorbing materials or micro-processing the light-absorbing film.Compared with the anisotropic materials commonly used in polarization detection,the preparation process of organic-inorganic hybrid perovskite films is mild,which has a lower cost,and can be applied to large-scale solution processing.Perovskite materials are easy to dissolve in the polar solvents used in conventional patterning.Besides,they have a tend of square flakegrowth,so complicated processes are needed to achieve a one-dimensional structure,which limits the patterning application of chemical perovskite materials in the field of polarization detection.Therefore,patterned MAPbI3 polycrystalline film is achieved in this dissertation using soft template imprinting combined with spin-coating and vapor-assisted methods.Further,a polarization detector with a good light response is constructed.The basic electronic performances and polarization characteristics of the photodetector based on the patterned MAPbI3 film are investigated and its polarization detection mechanism is discussed.Using PDMS as a seal,soft templates with one-dimensional micro-nano channel patterns having different feature sizes were prepared based on the optical disc grating patterns of CD and DVD respectively.The channel width and depth of the PDMS soft template based on the CD grating pattern are about 1.1μm,and 182 nm.When based on the DVD grating pattern,the channel width and depth are about 390.8 nm and 83.7 nm.The two sizes of PDMS soft templates have periodic and parallel one-dimensional micro-nano arrays.When used as a perovskite film imprint template,they have the advantages of easy demolding,small damage to imprinting materials,and simple processing.Patterned process of perovskite polycrystalline film has laid the foundation.Using template imprinting process combined with spin coating and vapor-phase assisted method,high-purity and high-quality patterned MAPbI3 polycrystalline films based on optical disc grating pattern were successfully prepared.Besides,the growth mechanism of the crystalline film is discussed.The channel width of the MAPbI3 polycrystalline film is about 1.35μm,and the channel depth is about 34.5 nm.The film can absorb light from400-800 nm.By testing the polarization absorption spectrum,the patterned MAPbI3polycrystalline film based on CD disc has good polarization properties and can be used as light absorption layer of the polarization photodetector.The patterned MAPbI3 thin-film detector with a planar structure was successfully constructed on the interdigital electrode through spin-coating.The planar structure detector exhibites a certain response to 400-800 nm photons and a polarization degree of it is about0.532.Vertical-structure detector based on the patterned MAPbI3 polycrystalline film is successfully constructed on the ITO substrate.The device showed a good response to light from 400-800nm.The photodetector has a fast response speed,including a rise time of3.16μs,a fall time of 3.26μs,and a detectivity of 2.44×109 Jones.By re-engraving the CD grating pattern structure,the patterned MAPbI3 polycrystalline thin-film photodetector has a high polarization ratio（≈0.548）.The correlation between the channel pattern of the patterned MAPbI3 polycrystalline thin film and the polarization characteristics of the constructed detector was further analyzed.Also,the imaging application of the vertically structured photodetector based on patterned MAPbI3 polycrystalline film was demonstrated. |
