Synthesis And Infrared Optoelectronic Properties Of Metal Halide Perovskite Nanoheterostructures

In recent years,owing to their high photoabsorption coefficient,long carrier lifetime,high defect tolerance,and other excellent properties,metal halide perovskite materials have attracted wide considerations.Meanwhile,the perovskite nanomaterials shows more advantages in the specific surface area and carrier transport as compared with the bulk perovskites.Therefore,the perovskite nanomaterials have been used to construct lots of high-performance optical,electronic,and optoelectronic devices.As the important unit of optoelectronic integrated devices,photodetectors have been well-developed owing to the emergence of nano-perovskites.The critical performances of the perovskite photodetectors,including photoresponsivity,on/off ratio,and response speed,are much better than the previously reported photodetectors based on other material systems.Consequently,perovskite nanomaterials have been recognized as the important anticipate in constructing high performance photodetectors.Despite the remarkable performances of perovskite optoelectronic devices,the light response of perovskite materials in the infrared band is limited due to the wide bandgap.However,the photodetections in the infrared band have extremely important applications,such as infrared imaging,infrared sensor,and infrared communication.Therefore,if the infrared photodetections of nano-perovskites can be improved,this material system will play more important role in constructing optoelectronic integrated devices.The construction of perovskite nanoheterostructures and the improvement of photogenerated carrier behaviors would be an efficient strategy to enhance the infrared photodetections of nano-perovskites.Therefore,in this thesis,through investigating the growth condition of perovskite nanomaterials,various halide perovskite heterostructures have been synthesized and realize the superior infrared photodetection performances.The following research results were obtained in this thesis:(1)Infrared telecommunication wavelength photodetections based on organic-inorganic hybrid perovskite thin-film/erbium silicate nanosheet heterostructureThe single-crystalline erbium silicate nanosheets with upconversion function were grown by chemical vapor deposition method,and the organic-inorganic hybrid perovskite thin-films were further prepared onto the erbium silicate nanosheet through combining vapor-phase and solution-phase methods,realizing the fabrication of perovskite thin-film/erbium silicate nanosheet heterostructure.Then,the optical investigations of heterostructures were performed.It indicates that,under the excitation of infrared light,the upconversion of the nanosheet can convert the infrared light into visible light,which can be absorbed by perovskite film.Owing to the excellent optical confinement of the nanosheet,the upconversion light can be effectively confined in the nanosheet cavity,and can be effectively coupled into the perovskite film through the nanosheet/perovskites interface.Experimental results and theoretical simulation proved the existence of this process.The heterostructure device has been fabricated and demonstrates significant photoelectric response in the?1.55?m near-infrared communication band,and the responsivity is much higher than the pristine perovskite materials and the reported silicon optoelectronic devices.At the same time,the photodetector has a fast response time of?900?s.These results have great significance for the development of perovskite optoelectronic devices(2)Infrared photodetections based on all-inorganic perovskite nanosheet/antimony trioxide nanoparticles heterostructureThe Cs Pb Br₃nanosheet/Sb₂O₃nanoparticles heterostructures were grown via vapor deposition method and superior infrared photodetections were realized.The growth behavior of heterostructure materials have been investigated.Through tuning the heating temperature of solid source,the sequential growth of Sb₂O₃nanoparticles and perovskite nanosheet materials can be realized.Meanwhile,it's observed that the growth behavior of perovskite nanomaterials strongly depends on the morphology of Sb₂O₃nanoparticles.When the Sb₂O₃is nanoparticles,the perovskite nanosheets grow onto nanoparticles,forming the heterostructure with large hetero-interface.Optical measurements indicate that the Sb₂O₃nanoparticles can prolong the carrier lifetime of perovskite nanosheet under excitation of 800 nm infrared light.This passivation can realize the efficient infared photoresponse of perovskite nanosheet.The photodetection device has been fabricated based on the as-grown heterostructures.Benefiting from the effective surface passivation of Sb₂O₃nanoparticles,the heterostructure detectors realize the superior infrared photodetection performances with the infrared photoresponsivity of 10²A/W.These results can further extend the application of perovskite nanomaterials in optoelectronic integrated devices.(3)Infrared photodetections based on all-inorganic perovskite nanoparticles/indium phosphide nanowire heterostructureThe In P nanowires with narrow bandgap were prepared by chemical vapor deposition method,and the inorganic perovskite nanoparticles were further grown onto the In P nanowires.Therefore,the perovskite nanoparticles/In P nanowire heterostructures were obtained and realize the superior infrared photodetections.The growth behavior and microstructure of the materials were investigated.It's observed that the perovskite nanoparticles can selectively grow onto In P nanowires,which should be attributed to that the surface of nanowires provides a nucleation site for the growth of perovskites due to the h high surface activity.Optical measurements indicate that the carriers in In P nanowire can be transferred into perovskite under light excitation,which can help to enhance the photoresponse of perovskite.The photodetection devices were fabricated based on the as-grown heterostructures.Benefiting from interface carrier transfer,the devices realize the superior infrared photodetections.Additionally,owing to the excellent performance of perovskite nanoparticles/In P nanowire heterostructures,we further grow the perovskite nanoparticles/In As nanowire heterostructures.This work may provide new materials for the construction of high-performance infrared devices.(4)Infrared photodetections based on all-inorganic perovskite nanosheet/gallium arsenide nanowire heterostructureThe perovskite single-crystalline nanosheet/Ga As nanowire heterostructures have been grown and exhibit the high-performance infrared photodetections.Ga As nanowires were prepared by chemical vapor deposition method.All inorganic perovskite single-crystalline nanosheet/Ga As nanowire heterostructures were then prepared via tuning the perovskite precursor vapor and deposition time.The growth behavior and microstructure of the heterostructure were investigated in detail.It's observed that the perovskite precursor vapor flow rate and deposition time have remarkable influences on the formation of nanosheet and quality of Ga As nanowire.Additionally,the perovskite nanosheets prefer to grow on the Ga As nanowires.Through combining the microstructure analysis and calculations,this growth behavior can be attributed to the high adsorption energy of Ga As nanowire surface.The optical behaviors of the heterostructures were investigated.The steady-state photoluminescence of the heterostructures confirm the remarkable carrier separation across the heterointerface,which will improve the photodetections of heterostructure.The photodetection devices were fabricated based on the as-grown heterostructures.Benefiting from the single-crystalline perovskite nanosheet,narrow bandgap of Ga As nanowire,and interfacial carrier transfer,the device can realize efficient and fast infrared photodetections.Lastly,we further tune the dimensionality of perovskite in the heterostructures and realize the perovskite nanowire/Ga As nanowire heterostructures through tuning the growth temperature,which are expected to further optimize the infrared photodetections of perovskite heterostructures.