Design And Synthesis Of Low-Dimensional Lead-Free Organic-Inorganic Hybrid Perovskites With Excellent Properties

In recent years,organic-inorganic hybrid perovskite materials have become potential candidates in photoelectric applications because of their excellent electrical and optical properties,especially their low-cost simple synthesis process.At present,lead-based hybrid perovskite shows excellent photoelectric properties,but the stability of materials and the toxicity of lead seriously hinder the large-scale application of these materials in the future;whereas low-dimensional hybrid perovskite materials have better stability and structural compatibility,to meet the requirements of practical applications.In view of this,this paper takes low-dimensional lead-free hybrid organic-inorganic perovskite as the main research object,and selects 3-isopropoxypropylamine,iodopropylamine,（S/R）-1-（4-aminophenyl）ethane Using organic cations such as amines,many examples of low-dimensional lead-free hybrid organic-inorganic perovskite materials were synthesized,and the related properties of the materials were studied.（1）Using iodopropylamine and 3-isopropoxypropylamine cations,two zero-dimensional lead-free hybrid perovskites（C₃H₉NI）₃Bi I₆（1）and（C₃H₉NI）₃Sb I₆（2）were successfully designed and synthesized,and one one-dimensional Non-lead hybrid perovskite(C₆H₁₅NO)₂Sb Br₅（3）.Large-size high-quality single crystals of these compounds were grown,and the differences in their structures and properties were systematically compared.The results show that for perovskite materials,iodine-based perovskite has a wider detection range than bromine-based perovskite,and as the dimension increases,the semiconductor performance and optoelectronic performance also have a good improvement.This work opens up more potentials for low-dimensional hybrid perovskites in the field of photodetection.（2）Utilizing iodopropylamine organic cations,a case of two-dimensional lead-free hybrid double perovskite material（C₃H₈IN）₄Ag Bi I₈（IPAB）was synthesized by using the heterovalent metal substitution method,which was synthesized in a short time by using the bottom seed crystal method The large size crystals of IPAB.The unique two-dimensional layered quantum well structure and narrow bandgap help to generate polarization-sensitive photoresponse in a wide spectral range,exhibiting high dichroic ratio(I_aph/I_cph≈1.23),large detectability of 10¹⁰Jones,and fast response time（～440μs）and better stability.This work provides a potential opportunity for the application of two-dimensional lead-free organic-inorganic hybrid double perovskite materials in the field of polarized light detection.（3）The Dion-Jacobson chiral polar double perovskite[S/R-4APEA]₂Ag Bi I₈·0.5H₂O（1-S/1-R）.For the first time,a pyroelectric-based self-driven photodetector has been realized in a lead-free double perovskite,which can not only detect a wide wavelength,but also greatly improve the photoresponse and detection rate.It is worth noting that by coupling chiral optical activity and photopyroelectric effect,pyroelectric-based circularly polarized light detection is realized,and its g_lph can reach 0.27 under zero bias.To the best of our knowledge,this is the first application of the photopyroelectric effect of halide hybrid perovskites in the field of self-driven circularly polarized light detection.The field of circularly polarized light detection opens up a new avenue.