Perovskite photoelectric memristors

混合有机-无机卤化铅钙钛矿（APbX，A：有机或无机阳离子，X：卤素阴离子，如Br、Cl、I）在光致发光领域引起了极大的兴趣，最近，由于其混合的电子和离子导电性以及大的吸收系数，在忆阻器领域也引起了极大的兴趣。最近，研究工作集中在用其他贵金属代替有毒的铅。尽管在提高无铅钙钛矿的环境稳定性方面取得了一些成功，但它们的光伏效率仍然很低，使得它们与它们的Pb类似物竞争。然而，这些材料被证明是更感兴趣的忆阻社区，因为它们的缺陷丰富的化学允许有效的忆阻开关，由于离子迁移诱导的导电丝的形成和破裂的形成。全无机和混合有机-无机无铅钙钛矿薄膜（例如双钙钛矿Cs2 AgBiBr 6）将在两端器件中进行研究，夹在ITO和Al垂直电极之间，或者在纳米间隙分离（<10 nm）的共面电极中，以开发作为人工突触的忆阻器件。前体材料和沉积工艺参数将根据所需的器件特性进行精心定制。纳米级薄膜的特点是与原子力显微镜和扫描电子显微镜和他们的直流电流-电压和阻抗特性将得到彻底的研究，以获得全面的了解的工作原理。它们的光电操作也将通过短光脉冲激发来探索，以实现光学控制的存储器和光子突触的发展。

Hybrid organic-inorganic lead halide perovskites (APbX, A: organic or inorganic cation, X: halide anion, such as Br, Cl, I) have attracted tremendous interest in photovoltaics and, recently, also in memristor community due to their mixed electronic and ionic conductivity as well as large absorption coefficient. Lately, research efforts have been concentrated on replacing toxic Pb with other nobler metals. Despite some success demonstrated with respect to increased environmental stability of lead-free perovskites, their photovoltaic efficiencies remain low to render them competitive to their Pb analogues. Nevertheless, those materials are proven to be of much more interest to the memristive community, as their defect-rich chemistry allows for effective memristive switching due to the formation of ion-migration-induced conductive filament formation and rupture. All-inorganic and hybrid organic-inorganic lead-free perovskite films (e.g. double perovskites Cs2AgBiBr6) will be investigated in two-terminal devices, either sandwiched between ITO and Al vertical electrodes, or in nanogap-separated (<10 nm) coplanar electrodes towards development of memristive devices operating as artificial synapses. The precursor materials and the deposition process parameters will be carefully tailored to the desired device properties. The nanoscale films will be characterised with atomic force microscopy and scanning electron microscopy and their DC current-voltage and impedance characteristics will be thoroughly studied to obtain a comprehensive understanding of the operational principle. Their photoelectric operation will be also explored via excitation with short light pulses towards optically controlled memories and development of photonic synapses.