Study Of CH₃NH₃PbI₃ Perovskite Nanowire Array Photodetectors

In recent years,due to the excellent optical and electrical properties of halide perovskites,such as high light absorption,low defect density,long carrier lifetime,etc.,there have been a lot of research in the fields of photodetection,laser,photovoltaic,etc.with application.However,due to ionic defects,grain boundaries,etc.in polycrystalline films,as well as the poor flexibility and complex process of bulk single crystals,the application potential of these traditionally structured perovskites is limited.The one-dimensional nanowire-structured perovskite single crystal shows greater development prospects in applications due to its optical anisotropy and excellent mechanical flexibility.In this work,the one-step method and the spatial confinement method were combined to fabricate the neatly arranged CH₃NH₃Pb I₃ perovskite nanowires array with complete morphology.After detailed characterization,it was proved that the crystalline quality is good,and the density of trap states is 1.5×10¹² cm^-3.On this basis,a CH₃NH₃Pb I₃ perovskite nanowire array photodetector was fabricated,which exhibited excellent photodetection performance in the visible-near-infrared band.The device obtained a light-dark ratio of 1.4×10⁶ under the illumination of a wavelength of 532 nm and an incident light intensity of 16.42m W/cm².Meanwhile,a photoresponsivity of 58.5 A/W and a specific detectivity of Jones of 1.96×10¹³ were obtained under low light intensity condition（0.16 m W/cm²）.Due to the excellent optoelectronic anisotropy brought by the higher aspect ratio,the device obtained a polarization ratio of 3.37:1,which shows great potential in the application of polarized light detection.Combined with the above work,a CH₃NH₃Pb I₃ perovskite nanowire/copper phthalocyanine heterojunction photodetector was fabricated.Although the introduction of the heterojunction slightly weakened the sensitivity of the device to polarized light（2.49:1）by affecting the microstructure,but in the same measurement condition,the photocurrent of the device is more than an order of magnitude higher than that of the nanowire array device in the 808 nm band,and the key performance parameters（photoresponsivity and external quantum efficiency）were increased to84.5 A/W and 1.97×10⁴%,respectively.