Study Of Solution-Processed High-Performance Perovskite/2D Materials Hybrid Photodetectors

Organic-inorganic hybrid perovskite materials represented by methylamino lead halides?C H₃NH₃PbX₃?have a significant advantage over traditional organic and inorganic semiconductor materials in the field of optoelectronics.They have developed rapidly in recent years and power conversion efficiency of perovskite solar cell has reached 22%which are currently reported.The perovskite material has low cost,high light-absorbing ability,adjustable forbidden band width,longer carrier diffusion length and lifetime,and low defect density,a t the same time,it has excellent bipolar carrier transmission,which are expected to realize high performance photodetectors.In this dissertation,a high performance perovskite photodetector is proposed.Graphite films grown by solution-chemical oxidation-reduction method instead of CVD method.Perovskite-graphene and perovskite/molybdenum disulfide hybrid heterojunction structures are built using the all-solution method.Besides,the intrinsic mechanism of bulk heterojunction structure to enhance the photoelectric response of perovskite has been discussed,and achieved Perovskite/two-dimensional material hybrid photodetector with high responsivity.A perovskite/graphene double layers heterojunction hybrid photodetector structure was designed and prepared.The high light absorption of perovskite materials and the high carrier mobility of graphene were used to achieve high response perovskite photodetector.High-quality,low-defect single-layer graphene oxide is assembled and chemically reduced by a solution method to obtain a reduced graphene oxide channel layer with high carrier mobility instead of a graphene film grown by CVD.The fabrication process of the high quality perovskite film deposited on the graphene film by the solution method are optimized by solvent engineering,crystallization treatment.The effects of the thickness of graphene,the thickness of the perovskite absorbing layer and the quality of the perovskite film on the photoelectric properties of the perovskite/graphene heterojunction hybrid photodetector were investigated.Optimized perovskite/graphene heterojunction hybrid photodetector with excellent photoelectric response characteristics:responsivity 62 A/W,response/recovery time less than 45 ms?optical wavelength:520 nm,optical power density:1.6 mW/cm²?.A perovskite/molybdenum disulfide heterojunction hybrid photodetector was fabricated on the reduced graphene oxide conductive channel by a solution process.Molybdenum disulfide nanosheets are uniformly dispersed in perovskite to construct a perovskite/molybdenum disulfide heterojunction structure,utilizing efficient charge transfer at the interface of perovskite/molybdenum disulfide?molybdenum disulfide is an electron acceptor?The bulk heterojunction structure provides more interfaces than the double-layer film structure.A high-quality perovskite/molybdenum disulfide heterojunction film and a high-performance photodetector are obtained with a maximum responsivity of 1.08×10⁴ A/W,the response/recovery time is less than 45 ms?optical wavelength:660 nm,optical power density:0.53?W/cm²?.The effects of molybdenum disulfide concentration and crystal quality on the photoelectric performance of bulk heterojunction photodetectors were studied.The optoelectronic properties were characterized systematically,and the intrinsic physics of the molybdenum disulfide forming heterojunction to improve photodetection performance was emphatically analyzed.mechanism.The feasibility of a flexible perovsk ite/molybdenum disulfide heterojunction photodetector was verified,and a flexible photodetector with high photoelectric detection performance and good bending resistance was realized.