Organic-Inorganic Hybrid Perovskite Micro-/Nano Single Crystal:Fabrication,Assembly,and Photodetector Application

Scale-up of organic-inorganic hybrid perovskite micro-/nano single crystals(PMNSCs)for integrated device application is difficult due to the location and morphology of PMNSCs which are usually stochastic and uneven in nature.Aiming at these critical issues,the following works have been carried out in this thesis:1.We report a simple one-step dip-coating method for the production of organic-inorganic hybrid perovskite nanoparticles(NPs)/organic semiconductor single crystals(OSSCs)hybrid structure,which can be fabricated into high-performance photodetectors with dual-band capability.ln this work,the size-controllable CH3NH3Pbl3 NPs were prepared by solvent exchange method.Then,the CH3NH3Pbl3 NPs were evenly located and dispersed on the surface of OSSCs by dip-coating method.The combination of CH3NH3PbI3 NPs and OSSCs in the hybrid structure is a physical effect,and the spectral response of the hybrid structure was remarkably expanded from ultraviolet to visible light region.Dual-band photodelcetor made of the hybrid structure exhibited a superior photoresponsivity of 1.72 × 104 A/W in the 252-780 nm region.Exploiting these unique features,we fabricated a matrix array of 10 × 10 pixels of the hybrid structure-based photodetectors,and demonstrated it to have an innovative application in secure communication.The successful preparation of perovskite NPs/OSSCs hybrid structure opens a way for the application of perovskite micro-/nano single crystals in dual-band photodetectors.2.We report the use of a saturated vapor-assisted crystallization method,to fabricate high-stability single-crystalline organic-inorganic hybrid perovskite nanowires(NWs).The single-crystalline CH3NH3PbI3 NWs have a smooth surface with few grain boundaries and surface defects due to the elimination of moisture intrusion in the vapor atmosphere.Photodetectors based on the high-stability CH3NH3PbI3 NWs demonstrated excellent device performance in terms of high-sensitivity for visible light detection with responsivity as high as 460 A/W.specific detectivity as high as 2.6 × 1013 Jones,submillisecond response time,and long-term air stability over 45 days.The stability is among the best in CH3NH3PbI3 NW-based photodetectors.Kelvin probe force microscopy measurement was performed to clarify the origin of the outstanding photoconductive properties of the CH3NH3PbI3 NWs.The successful preparation of single-crystalline perovskite NWs further improves the stability of-photodetectors based on perovskite micro-/nano single crystals.3.We report the fabrication of large-area single-crystalline organic-inorganic hybrid perovskite microwire(MW)arrays by a simple,low-cost blade coating method on flexible substrates.When a blade was put at the front of the solution,a meniscus would be formed,which promotes the self-assembly of single-crystalline CH3NH3PbI3 MW array.We studied the photoelectric properties of the MW array by micro-area photocurrent scanning technology.Within the scanning range,the MW array reveals highly uniform photocurrents,which lays a material foundation for the construction of high-resolution image sensor.The MW array-based photodetectors exhibited a high performance,with a broad expected linear dynamic range of 144 dB,responsivity of 13.57 A/W,and specific detectivity of 5.25 × 1012 Jones.In addition,the device has good bending stability with a bending time up to 100,000.The flexible image sensor based on MW array could work in different bending directions and showed super high resolution.The successful preparation of large-area and high-integrated single-crystalline perovskite MW array on flexible substrate realizes the application of perovskite micro-/nano single crystals in flexible photodetectors and promotes the development of integration,miniaturization and lightweight of devices.4.We report a microchannel-confined crystallization strategy to grow large-area and highly oriented single-crystalline organic-inorganic hybrid perovskite MW arrays with excellent photoelectric properties.In this method,a highly ordered template with microchannels is used to control the growth position/orientation of the CH3NH3PbI3 MW array.Microchannels offer restriction to solution and reduce the size of the contact line,which avoids turbulent mass transport and decreases nucleation density.This ensures homogeneous nucleation and thus forms one single crystal in the microchannel.Subsequently.the epitaxial growth of the single crystal in each microchannel occurs under the continuous blade-coating process,leading to the formation of long single-crystalline MW with consistent crystal orientation and uniform photocurrent.Due to the presence of the microchannels template.the CH3NH3PbI3 MW array can be used to construct photodetectors with vertical structure.The device showed a high responsivity of 6.66 × 103 A W-1,a high specific detectivity of 6.85 × 1012 Jones,and a broad linear dynamic range of 88 dB.Benefiting from the high-performance photodetectors,image sensor consisting of 10 × 10 addressable photodetector-array successfully demonstrated a clear imaging capability.The successful preparation of large-area and highly oriented single-crystalline perovskite MW arrays enables perovskite micro-/nano single crystals to be used in high-performance and addressable integrated optoelectronic devices.