Perovskite photoelectric memristors

杂化有机-无机卤化铅钙钛矿（APbX， A：有机或无机阳离子，X：卤化阴离子，如Br， Cl， I）由于其混合的电子和离子电导率以及大的吸收系数，在光伏领域引起了极大的兴趣，最近也在忆阻器界引起了极大的兴趣。最近，研究工作集中在用其他更高贵的金属代替有毒的铅。尽管无铅钙钛矿在提高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，无法与铅类似物竞争。然而，这些材料被证明是记忆体社区更感兴趣的，因为它们的富缺陷化学允许有效的记忆体开关，由于离子迁移诱导的导电丝形成和断裂的形成。全无机和杂化有机-无机无铅钙钛矿薄膜（例如双钙钛矿Cs2AgBiBr6）将在双端器件中进行研究，无论是夹在ITO和Al垂直电极之间，还是在纳米间隙分离（<10 nm）共面电极中，以开发作为人工突触操作的记忆器件。前驱体材料和沉积工艺参数将仔细定制所需的器件性能。纳米级薄膜将用原子力显微镜和扫描电子显微镜进行表征，并将深入研究其直流电压和阻抗特性，以全面了解其工作原理。它们的光电操作也将通过短光脉冲激发来探索光控记忆和光子突触的发展。

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.