Chen Haowen, Dong Mingdong, Hu Yang, Lin Ting, Zhang Qinghua, Guo Er-Jia, Gu Lin, Wu Jie, Lu Qiyang
Zhejiang University, Hangzhou 310027, People's Republic of China.
School of Engineering, Westlake University, Hangzhou 310030, People's Republic of China.
Nano Lett. 2022 Nov 23;22(22):8983-8990. doi: 10.1021/acs.nanolett.2c03229. Epub 2022 Nov 4.
Protonation can be used to tune diverse physical and chemical properties of functional oxides. Although protonation of nickelate perovskites has been reported, details on the crystal structure of the protonated phase and a quantitative understanding of the effect of protons on physical properties are still lacking. Therefore, in this work, we select NdNiO (NNO) as a model system to understand the protonation process from pristine NNO to protonated HNdNiO (H-NNO). We used a reliable electrochemical method with well-defined reference electrode to trigger the protonation-induced phase transition. We found that the protonated H-NNO phase showed a colossal ∼13% lattice expansion caused by a large tilt of NiO octahedra and displacement of Nd cations. Importantly, we further designed a novel device configuration to induce a gradient of proton concentration into a single NNO thin film to establish a quantitative correlation between the proton concentration and the lattice constant and transport property of H-NNO.
质子化可用于调节功能氧化物的多种物理和化学性质。尽管已报道了镍酸盐钙钛矿的质子化，但关于质子化相的晶体结构细节以及对质子对物理性质影响的定量理解仍很缺乏。因此，在本工作中，我们选择NdNiO（NNO）作为模型体系，以了解从原始NNO到质子化的HNdNiO（H-NNO）的质子化过程。我们使用了具有明确参比电极的可靠电化学方法来触发质子化诱导的相变。我们发现，质子化的H-NNO相由于NiO八面体的大倾斜和Nd阳离子的位移而显示出约13%的巨大晶格膨胀。重要的是，我们进一步设计了一种新颖的器件结构，以在单个NNO薄膜中诱导质子浓度梯度，从而建立质子浓度与H-NNO的晶格常数和输运性质之间的定量相关性。
