Preparation And Optoelectronic Properties Of Cs-X-I(X=Pb,Cu) Deposited By Vacuum Physics

In the recent,perovskite have become a“superstar”owing to their remarkable characteristics.It has the advantages of high light absorption coefficient and carrier mobility,low defect density of states,simple processing technique,tunable emission wavelength and longer carrier diffusion distance.The application direction of perovskite extends from solar cells to the light detector(PD),light-emitting diode(LED),laser(LD)and other photoelectric devices and has made breakthrough progress.At present,organic-inorganic hybrid perovskite and all-inorganic perovskite are mainly prepared by solution method,which cannot overcome the problems of many defects and non-uniformity,which become the bottleneck of their application in photoelectric devices.In this paper,all inorganic perovskite Cs-X-I(X=Pb,Cu)materials were prepared by pulsed laser deposition,vacuum evaporation and high pressure laser sputtering.By precisely adjusting the growth parameters,laser frequency and other process parameters,the defect density of the material is effectively reduced,and the controllable growth of high-quality Cs-X-I(X=Pb,Cu)perovskite material is realized.On this basis,the application of Cs-X-I(X=Pb,Cu)perovskite in photoelectric devices was studied.This study not only provides theoretical basis and technical support for the vacuum preparation of high-quality perovskite thin films,but also provides a feasible technical approach for the application of perovskite photoelectric devices.The main work of this paper includes the following contents:1.High quality CsPbI₃ thin films were prepared by pulsed laser deposition.In this work,CsPbI₃ thin films were prepared by pulsed laser deposition.The morphology,structure,phase and optical properties of CsPbI₃ thin films were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD)and photoluminescence(PL).The results show that the high crystal quality of CsPbI₃ films were prepared by PLD,and the films were dense without obvious voids.The CsPbI₃ films shows a?phase In addition,the CsPbI₃/n-Si heterostructure device was constructed and fabricated,and the optical response characteristics of the device were studied.The experimental data show that the CsPbI₃/n-Si heterostructure device has diode rectifying characteristics,the on/off ratio is about 70,the light responsivity of the device is 51.9 m A/W(-1 V)under 695 nm light,and the response speed is fast.2.Cubic CsPbI₃ has special photoelectric properties.We have prepared cubic CsPbI₃nanostructures with excellent stability on n-Si by high pressure laser sputtering.The photoelectric properties of CsPbI₃nanostructure/n-Si and CsPbI₃ nanostructure/Ti O₂nanorod heterojunction photodetectors were studied.The results show that both heterojunction detectors show good optical detection performance,which provides a new idea for the preparation of stable cubic CsPbI₃.3.High quality CsCu₂I₃ thin films were prepared by vacuum thermal evaporation technology,and their applications in deep UV detector devices were realized.In the experiment,we prepared Cs-Cu-I thin films with different structures by adjusting the composition ratio of evaporation source.The results show that when the ratio of evaporation source is 1:2(Cs I:Cu I),the film is CsCu₂I₃.When the ratio of evaporation source is 1:1(Cs I:Cu I),the film is a mixture of CsCu₂I₃ and Cs₃Cu₂I₅.When the ratio of evaporation source is 3:2(Cs I:Cu I),the film is mainly composed of Cs₃Cu₂I₅.In addition,we use Cu I thin film as buffer layer to grow CsCu₂I₃ thin film,which can effectively improve the growth quality of CsCu₂I₃ thin film,reduce the composition of Cs₃Cu₂I₅ in the film,and the photoelectric performance of photoelectric detector based on CsCu₂I₃ is also greatly improved.This work provides a new way to prepare high-quality Pb free perovskite by vacuum technology,and proposes and verifies the technical route of using Cu I as buffer layer to obtain the CsCu₂I₃ thin films with pure phase.