Synthesis And Photoelectric Properties Of Rb₂CuBr₃

Perovskite materials have attracted extensive attention in the field of optoelectronics due to their excellent characteristics such as carrier transport balance,large optical absorption coefficient,adjustable band gap and low temperature solution treatment technology,but their commercial development and application are seriously hindered by lead toxicity and instability.Therefore,the search for non-toxic and stable perovskite materials has become a research trend.In recent years,new copper based perovskite derivatives have become a research hotspot,and Rb₂CuBr₃ is one of them.It has one-dimensional lattice characteristics,is a direct bandgap wide bandgap semiconductor material,currently mainly synthesized by solution method,its one-dimensional lattice characteristics lead to its easy to form a rod or linear structure.In order to expand the application of this structure,Rb₂CuBr₃ was prepared by vacuum thermal evaporation in this paper,and the application potential of Rb₂CuBr₃ in ultraviolet photodetection was confirmed.The main research contents of this paper include the following two aspects:First,Rb₂CuBr₃ micron rod with variable size was prepared by solution synthesis method.Through the control of the three reaction variables of solution concentration,drying temperature and solvent ratio,we concluded that the larger the solution concentration,the larger the size of the rod structure;Too high drying temperature is easy to destroy the formation of rod structure,usually at room temperature is better;DMSO can promote the growth of rod-like structure.In addition,we also characterized the material properties of the micron rod.The phase and morphology results showed that although there was a heterophase,the structure of Rb₂CuBr₃ micron rod was also well formed.The spectral results show that the peak of the emission spectrum is 385nm,the half-peak width is 45 nm,and there is a Stokes shift of 100 nm relative to the absorption peak.The optical band gap is calculated by the Tauc plot formula,and the optical band gap is 3.74e V.Second,Rb₂CuBr₃ thin film was prepared by vacuum evaporation,and the phase,morphology and spectral characteristics of the thin film were characterized.Different heterojunction detectors were constructed on n-Si and n-Ga N epitaxial substrates.The Rb₂CuBr₃/Si heterojunction UV detector has good spectral selectivity and light response characteristics.Under-0.5V bias and 220nm illumination,the peak response and specific measurement are 169m A/W and 3.86×10¹¹ Jones,respectively.The Rb₂CuBr₃/Ga N heterojunction UV detector has a dual-band UV detection feature with high optical responsiveness and specific detectivity in the<300nm and 300-400nm ranges.The device’s light-dark current on/off ratio reaches 109 at a-2.5V bias.Under a-1.5V bias,the peak responsivity at 350nm is 45.6m A/W,corresponding to a specific detectiveness of 5.26×10¹¹ Jones.Moreover,the heterojunction photodetector has good reproducibility and stability at negative bias voltage below 2V.Compared with p-Rb₂CuBr₃/n-Si heterojunction detector,the optical response time and recovery time are significantly improved to 58ms and 38ms respectively.In addition,the device has excellent spectral selectivity.These results show that the Rb₂CuBr₃/Ga N heterojunction detector has better UV detection performance.