具有超低开关电场的可控的易失性至非易失性单晶无铅双钙钛矿忆阻器

Controllable volatile-to-nonvolatile memristive switching in single-crystal lead-free double perovskite with ultralow switching electric field

全无机无铅双钙钛矿由于其优异的电子传输能力、高光敏性、低毒性和环境稳定性,为电子/光电存储器件提供了潜在的材料.然而,钙钛矿薄膜的多晶性质严重限制了器件性能.在此,我们展示了一种基于单晶双钙钛矿Cs_(2)AgBiBr_(6)的高性能忆阻器,其具有6.67×10^(4)V m^(-1)的超低开关电场和10^(7)的高电流开/关比.值得注意的是,Cs_(2)AgBiBr_(6)的电阻开关行为与单晶钙钛矿的厚度相关,当单晶厚度从100到800 nm变化时,忆阻器从易失性的阈值开关行为演变为非易失性的忆阻开关行为.元素分析表明,Cs_(2)AgBiBr_(6)中导电通道的形成与具有低活化能Br空位的迁移有关.此外,形成的导电通道可以被具有不同波长和强度的光照湮灭,从而实现具有单独的电写入和光擦除的光电存储器.我们的研究结果为单晶钙钛矿中的离子迁移提供了深刻的见解,并为其在未来的电子和光电存储器中的应用提供了理论基础.

All-inorganic lead-free double perovskite offers a potential material platform for electronic or optoelectronic memory devices owing to its ionic migration-based electrical transport,high photosensitivity,low toxicity,and environmental stability.However,the commonly used polycrystalline perovskite films severely restrict device performance.Herein,we demonstrate a high-performance memristor based on single-crystal double perovskite Cs_(2)AgBiBr_(6)with an ultralow switching electric field of 6.67×10^(4)V m^(-1)and a high current on/off ratio of 10^(7).Remarkably,the resistive switching of Cs_(2)AgBiBr_(6)is found to be thickness-dependent,which evolves from volatile threshold to nonvolatile resistance switching with the crystal thickness from 100 to 800 nm.Elemental analysis reveals that the formation of conductive channels in Cs_(2)AgBiBr_(6)is associated with the migration of Br vacancies with low activation energy.In addition,the formed conductive channels can be annihilated by light illumination with controlled wavelength and intensity,which leads to the realization of optoelectronic memories with separate electrical-writing and optical-erasing processes.Our findings provide deep insights into the ionic migration in single-crystal perovskite and pave the way for its future application in electronic and optoelectronic memory devices.