Preparation And Research Of Two-dimensional Perovskite Materials In Different Optoelectronic Devices

With the continued advancement of numerous revolutionary optoelectronic technologies,the generation of efficient and digitized optoelectronic devices has become the primary objective of researchers.Under the guidance of this objective,the selection and design of sophisticated device architectures and innovative optoelectronic materials have become the pivotal direction to propel the advancement of optoelectronic technology in the future.Perovskite（PVK）materials have become one of the popular options for a series of optoelectronic devices due to their excellent photoelectric properties,including bipolar carrier transport characteristics,high light absorption coefficient,tunable band gap,high carrier mobility,long carrier lifetime and diffusion length.However,PVK materials face the challenge of poor stability in indoor environment,which urgently needs to be addressed.In recent years,two-dimensional perovskite（2D PVK）materials have exhibited improved environmental stability,presenting a promising avenue for practical commercial applications.2D PVK materials not only integrate the excellent photoelectric properties of 2D materials and PVK materials,but can also be fabricated using low-cost methods.2D PVK exhibits unique features that are not present in three-dimensional perovskite（3D PVK）,such as the enhanced environmental stability provided by hydrophobic organic moieties,the creation of quantum well structures due to the interlocking of organic and inorganic layers,and the utilization of organic components as insulating layers to erect barriers,generating anisotropy on different crystal planes.Moreover,the formation of a barrier layer in 2D PVK can effectively mitigate ion migration and prevent the crystal structure from being compromised,thereby prolonging the device’s service life and stability.However,the optoelectronic devices utilizing 2D PVK materials require optimization and improvement of both the preparation process and the device performance.In this study,2D PVK materials are the key focus of investigation.Through the design and synthesis of organic molecules,2D（PEA）₂Pb I₄ photodetectors and 2D Cs Pb I₃ solar cells are successfully fabricated.The photoelectric device performance is characterized in various application environments,and the synthesis of basic raw materials,the device fabrication process,as well as the optimization of their performance,are accomplished.The main research contents include the following two aspects:（1）Under the condition of low annealing temperature（80°C）and no other special treatment,phenylethylamine（PEA）organic molecule was selected to prepare high-quality two-dimensional PVK（PEA）₂Pb I₄ thin film by solution method,so as to make a horizontal photoconductive photodetector.The structure,morphology and optical properties of PVK thin film,as well as the performance and stability of photoelectric devices were comprehensive characterized.The results indicate that this simple photodetector has a very low dark current(10^-11 A),good responsiveness（107 m A/W）at a wavelength of 450 nm,a very high detection rate(2.05×10¹² Jones)and a fast response time（250μs/330μs）,which can be maintained after 1200 s of continuous controlled light exposure.95%performance.In addition,the device can still maintain good detection ability for a month.This research offers a promising pathway for advancing the development of robust and high-performing optoelectronic devices.（2）The 2D（CF₃PEA）₂Cs₄Pb₅I₁₆ solar cell was successfully generated by selecting a 2-（4-Trifluoromethyl-phenyl）-ethylamine（CF₃PEA）organic molecule as the barrier layer,which exhibited improved stability.This is to capitalize on the hydrophobicity of the organic cation and the potential to create a spatial site resistance effect to enhance environmental stability,phase stability,and ion mobility.Moreover,in the preparation process,isopropanol（IPA）was specifically chosen as a anti-solvent to treat the surface of the PVK films to optimize the coverage of the film and fine-tune the photovoltaic performance,leading to a photovoltaic conversion efficiency（PCE）of up to 15.69%.This 2D RP-type Cs Pb I₃ solar cell can advance the research of photovoltaic devices and pave the way for future commercial applications.