Preparation Of Yb³⁺Doped CsPbCl₃ Perovskite Photodetectors By Thermal Evaporation

In this research,we fabricated Yb³⁺-doped CsPbCl₃ perovskite photodetectors（PDs）by thermal evaporation and annealing at 85℃ on a Si/SiO₂ substrate,and investigated their surface morphology,crystal structure,and optoelectronic properties.A silver electrode was used to connect the Si to the top CsPbCl₃ perovskite layer cross middle 300nm SiO₂.Our results showed that the devices exhibited high responsivity at wavelengths of420 nm,680 nm,and 980 nm,with maximum values of 2364,3766,and 268 A/W,respectively.Based on UV photoelectron spectroscopy（UPS）and X-ray photoelectron spectroscopy（XPS）characterization results,we attributed this photoresponse behavior to the respective absorption of photons by CsPbCl₃ and Si.We also prepared Yb³⁺-doped CsPbCl₃ PDs with the structure CsPbCl₃（50 nm）/YbCl3（x nm）/CsPbCl₃（50 nm）,while X is in the range of 0-40nm,and characterized their exciton dynamics using steadystate and transient PL as well as space charge limited current（SCLC）mode.Our findings indicated that Yb³⁺doping can reduce the exciton lifetime of perovskite at 420 nm,decrease the trap density of the material and increase carrier mobility,leading to a significant improvement of the photoresponse performance of the PDs.Furthermore,we concluded that the photoresponse in a wide spectral range resulted from the Yb³⁺upconversion process and quantum cutting effect.