| Metal halide perovskite semiconductor materials have many excellent photoelectric properties,such as high carrier mobility,low defect density,good light absorption,exllent photoelectric conversion efficiency,strong defect tolerance,high color purity and wide color gamut,etc.It has shown great potential applications in renewable energy utilization,new generation flexible high-definition display,communication,lighting equipment,semiconductor microelectronics,energy and environmental photocatalyst,and relative fields.Since it was the firstly applied in solar cell devices,it has attracted much interest in highquality growth of perovskite thin films and its wide application.In the past decade,the field of perovskite optoelectronics has been rapidly developed.For example,the efficiency of perovskite solar cell has exceeded 25%,the efficiency of perovskite green and red lightemitting diodes have over 20%,and the room temperature optically pumped perovskite continuous-wave laser has been successfully realized.The fundamental research on perovskite materials and the construction of high-performance devices have always been the research hotspot.However,due to the soft lattice characteristics of perovskite and symmetrical crystal structure,the growth of low-dimensional perovskite materials and the construction of correlative high-performance devices are still challenge in the field.This thesis focuses on the key issue in the field of high-performance perovskite optoelectronic devices,involving the perspective of material design and synthesis,and high-quality low dimensional perovskite CsPbBr3 single crystal growth.The main contributions of this thesis includes the following parts:1、The growth of large area,ultra-thin all inorganic perovskite CsPbBr3 thin films have been studied in depth.Perovskite single crystal films with the size nearly centimeter and thickness less than 100 nm have been achieved.The results show that the films are high quality single crystals with excellent optical and electrical properties,narrow half peak width(13 nm),high carrier mobility(45 cm2v-1s-1),low defect density(5.8×1011 cm-3),long carrier diffusion length(4.7 μm).At the same time,the experimental results show that reaction temperature,precursor concentration and surfactant content significantly affect the nucleation,growth and anisotropic growth process of the films.Moreover,the film thickness can be adjusted successfully by facile adjusting the content of surfactant,and the controllable growth of films in the thickness range of 100～1000 nm is achieved.2、Super long,high yield and high quality single crystal CsPbBr3 nanowires were grown by one-step solution method at room temperature.The growth mechanism of nanowires was revealed through the detailed study on the nucleation and growth process of nanowires.The results showed that the growth of nanowires was a spiral growth mode driven by surface energy.This mode was first reported for CsPbBr3 perovskite nanowires in the solution growth.The existence of methanol in the reaction system was the key factor leading to the anisotropic growth of nanowires,methanol played a major role that adjust the chemical reaction microenvironment during the growth stage by weak dissolution of cesium bromide,the surface energy of nanowires is decreased and the anisotropic growth of nanowires is accelerated.At the same time,the prepared nanowires have excellent environmental stability,it have no obvious changes in structure and optical properties after stored in air for 5 months.Through a simple ion exchange process,the composition(CsPbCl3,CsPbI3),band gap(1.8-2.88 eV)and optical properties(PL range from 430 to 690 nm)of the nano wires can be continuously adjusted.The photodetectors based on nanowires show excellent optical detection performance.The light detection responsivity reaches 4923 A/W,the external quantum efficiency reaches 13784%,and the detection is 3.6×1013 Jones.At the same time,the photodetectors have fast response ability,the raise and fall time of the device are 0.547 ms and 0.916 ms,respectively.3、The single crystal halide perovskite type resistive memory with high quality all inorganic CsPbBr3 film was constructed,and its device performance was studied in detail.The results show that the CsPbBr3 single crystal perovskite film resistive memory exhibits bipolar switching characteristics and outstanding device performance.The switching ratio exceeds 109,which is the highest record of halide perovskite resistive memory.The device has the characteristics of low power consumption(10-8 w),high reliability(1.0×104),low set and reset voltage(+0.6 V.-0.5 V).The high performance of resistive memory comes from three aspects:first,the active layer of perovskite single crystal thin film has high crystallization quality,low defect density,low carrier concentration,and appropriate film thickness;second,the Schottky barrier formed on the surface of perovskite film by low work function silver electrode,long depletion zone and good interface contact between electrode and material(interface parameter is 0.3)lead to the high resistance state of device has ultrahigh resistance;third,the ion migration of perovskite film and the form silver wire which silver ion diffusion and nucleation growth driven by electric field dendrite conduction,makes resistive memory have low resistance state. |
