| In recent years,the research of organic-inorganic halide perovskites in the field of photovoltaics and light-emitting diodes has exploded.At present,the photovoltaic efficiency of three-dimensional perovskite solar cells has exceeded 25.6%.However,the poor inherent stability of 3D perovskites to moisture,heat,and light limits their further development.2D layered hybrid perovskites are due to their excellent charge transport,good stability,and natural quantum well structure has great application potential in the field of photodetection.Self-powered photodetection driven by Ferroelectric can achieve light signal sensing without external power incentives.Therefore,the two-dimensional hybrid perovskite combined with excellent semiconductor characteristics and ferroelectricity shows huge potential in the next-generation optoelectric components.in this thesis,the photodetection properties of organic-inorganic two-dimensional hybrid perovskite ferroelectric(EA)2(MA)2Pb3Br10 were systematically explored,and the photodetection properties and ferroelectric photovoltaic phenomena of different thicknesses were studied.The effects of a novel heterojunction composed of perovskite and Mo S2 and tin doping on the photodetection performance of perovskite were explored.The main contents are as follows:1.The photodetection properties and ferroelectric photovoltaic phenomena of ferroelectric two-dimensional perovskite(EA)2(MA)2Pb3Br10 were studied.The dark current of the bulk(EA)2(MA)2Pb3Br10 perovskite is 1.4×10-12A.When the applied voltage is 1V and the incident light power is 16.7?Wcm-2,the responsivity,external quantum efficiency,specific detectivity is 0.234 A W-1,72%,1.97×1012Jones.The photocurrent induced by ferroelectric spontaneous polarization can be maintained for about three hours.The dark current of the few-layer(EA)2(MA)2Pb3Br10 perovskite is6.3×10-13A.When the voltage is 1 V and the incident light power is 18?W cm-2,the responsivity,external quantum efficiency,specific detectivity are 0.09 A W-1,28.8%and8.4×1011Jones.The photocurrent induced by ferroelectric spontaneous polarization can be maintained for about twenty minutes.2.We designed two structures of Mo S2 and perovskite heterojunction devices.Compared with thin-layer perovskite devices,the first vertical structure has slightly improved responsivity,external quantum efficiency and detection rate,but The linear response range of this device is much larger than that of thin-layer perovskite devices.In the second structure,we reproducibly found a negative photoelectric response phenomenon caused by the formation of a vertical electric field due to the spontaneous ferroelectric polarization induced by the charge-transfer excitons under illumination.3.In order to avoid the toxicity of lead in the(EA)2(MA)2Pb3Br10 photodetector and the pollution to the environment,we designed(EA)2(MA)2Pb3Br10 photodetector doped with 5%,25%,50%and 100%tin element to investigate the effect of Sn doping on the photoelectric properties of perovskites.When the Sn doping ratio is lower than 25%,the photoelectric conversion capability of the perovskite photodetector is stronger as the Sn doping ratio increases.When the Sn doping ratio is 5%and 25%,the responsivity is respectively 1.5 times and 20 times higher.When the Sn element doping ratio is higher than 25%,the device performance is degraded due to the instability of Sn element. |
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