High-throughput sequential excitation for nanoscale mapping of electrochemical strain in granular ceria
High-throughput sequential excitation for nanoscale mapping of electrochemical strain in granular ceria
复制标题
DOI：
10.1039/c9nr07438d
复制
发表时间：
2019-12-28
期刊：
影响因子：
6.7
通讯作者：
Li, Jiangyu
中科院分区：
文献类型：
--
作者：
Huang, Boyuan;Esfahan, Ehsan Nasr;Li, Jiangyu
基于动态应变的原子力显微镜(AFM)模式由于不能准确地跟踪粗糙地形下的接触共振而在发生最感兴趣的物理现象的界面处失效。为了克服这一困难，我们开发了一种高通量顺序激励原子力显微镜，它以高保真和高效的方式捕获探针-样品相互作用的接触动力学，在以顺序方式激励的频率范围内获取每个像素上的数据光谱。以具有电化学活性的颗粒状CeO_3为例，我们以高空间分辨率精确地将线性和二次电化学应变映射到传统方法所不能解决的晶界。增强的电化学响应指向在晶界的空间电荷区积累的小极化子，这被认为是纳米晶CeO2电子导电性增强的原因。通过物理信息的主成分分析(PCA)可以非常有效地处理数据频谱，将数据处理速度提高了几个数量级。这种方法可以应用于各种原子力显微镜模式，以研究纳米尺度上的各种材料和结构。
Dynamic strain based atomic force microscopy (AFM) modes often fail at the interfaces where the most interesting physics occurs because of their incapability of tracking contact resonance accurately under rough topography. To overcome this difficulty, we develop a high-throughput sequential excitation AFM that captures contact dynamics of probe-sample interactions with high fidelity and efficiency, acquiring the spectrum of data on each pixel over a range of frequencies that are excited in a sequential manner. Using electrochemically active granular ceria as an example, we map both linear and quadratic electrochemical strain accurately across grain boundaries with high spatial resolution where the conventional approach fails. The enhanced electrochemical responses point to the accumulation of small polarons in the space charge region at the grain boundaries, thought to be responsible for the enhanced electronic conductivity in nanocrystalline ceria. The spectrum of data can be processed very efficiently by physics-informed principal component analysis (PCA), speeding data processing by several orders of magnitude. This approach can be applied to a variety of AFM modes for studying a wide range of materials and structures on the nanoscale.