Multi-Element Topochemical-Molten Salt Synthesis of One-Dimensional Piezoelectric Perovskite

摘要

class="head no_bottom_margin" id="sec1title">IntroductionOne-dimensional (1D) micro-nanomaterials have fascinated wide interest owing to their 2D confinement structure and exotic mechanical, electrical, and optical properties (, , , , , , , , , , , ). For flexible electronic devices (, , , href="#bib46" rid="bib46" class=" bibr popnode">Yang et al., 2012a, href="#bib47" rid="bib47" class=" bibr popnode">Yang et al., 2012b, href="#bib48" rid="bib48" class=" bibr popnode">Yang et al., 2012c), which exhibit great significance for viable economic growth and the enhancement of human quality of life, the 1D materials are highly desirable, and a wide range of 1D materials-based flexible devices such as field-effect transistors (href="#bib31" rid="bib31" class=" bibr popnode">Qing et al., 2014), flexible display devices (href="#bib38" rid="bib38" class=" bibr popnode">Wang et al., 2017), flexible photodetectors (href="#bib58" rid="bib58" class=" bibr popnode">Zhou et al., 2018), flexible sensors (href="#bib10" rid="bib10" class=" bibr popnode">Deutz et al., 2017, href="#bib33" rid="bib33" class=" bibr popnode">Rim et al., 2016), and flexible energy storage devices (href="#bib13" rid="bib13" class=" bibr popnode">Gao et al., 2016, href="#bib28" rid="bib28" class=" bibr popnode">Park et al., 2017, href="#bib9" rid="bib9" class=" bibr popnode">Deng et al., 2018, href="#bib15" rid="bib15" class=" bibr popnode">Guo et al., 2012) have been demonstrated to show superior performance than their counterparts with arbitrary shapes.Perovskite materials, owing to their applications in piezoelectric, ferroelectric, solar cells, and other fields, arouse a research boom (href="#bib5" rid="bib5" class=" bibr popnode">Burschka et al., 2013, href="#bib1" rid="bib1" class=" bibr popnode">Abdi-Jalebi et al., 2018, href="#bib3" rid="bib3" class=" bibr popnode">Becker et al., 2018, href="#bib8" rid="bib8" class=" bibr popnode">Christians et al., 2018, href="#bib11" rid="bib11" class=" bibr popnode">Domanski et al., 2018, href="#bib54" rid="bib54" class=" bibr popnode">Zhang et al., 2018a, href="#bib55" rid="bib55" class=" bibr popnode">Zhang et al., 2018b, href="#bib49" rid="bib49" class=" bibr popnode">Yang et al., 2019, href="#bib40" rid="bib40" class=" bibr popnode">Wu et al., 2012a, href="#bib41" rid="bib41" class=" bibr popnode">Wu et al., 2012b). The structure of perovskite materials is mainly ABO3-type of cubic or pseudo cubic phase. Generally, the shape of crystalline particles depends on their intrinsic structure, which means that materials with cubic phase usually form isotropic particles (href="#bib29" rid="bib29" class=" bibr popnode">Pribosic et al., 2005). Meanwhile, owing to the demand for various properties, A-sites and B-sites of perovskites are doped with multi-elements mainly via solid-state method (href="#bib57" rid="bib57" class=" bibr popnode">Zheng et al., 2018, href="#bib42" rid="bib42" class=" bibr popnode">Wu et al., 2016, href="#bib30" rid="bib30" class=" bibr popnode">Qin et al., 2016, href="#bib21" rid="bib21" class=" bibr popnode">Li et al., 2018, href="#bib22" rid="bib22" class=" bibr popnode">Liu et al., 2018). 1D perovskites materials, because of their unique electronic, nonlinear optical probe and mechanical properties, have potential in various fields (href="#bib32" rid="bib32" class=" bibr popnode">Ren et al., 2010, href="#bib25" rid="bib25" class=" bibr popnode">Nakayama et al., 2007, href="#bib14" rid="bib14" class=" bibr popnode">Gao et al., 2018, href="#bib46" rid="bib46" class=" bibr popnode">Yang et al., 2012a, href="#bib47" rid="bib47" class=" bibr popnode">Yang et al., 2012b, href="#bib48" rid="bib48" class=" bibr popnode">Yang et al., 2012c, href="#bib40" rid="bib40" class=" bibr popnode">Wu et al., 2012a, href="#bib41" rid="bib41" class=" bibr popnode">Wu et al., 2012b). To further improve performance, it is critical to achieve 1D multi-perovskite materials, which can incorporate 1D structural design into perovskites (href="#bib52" rid="bib52" class=" bibr popnode">Zhai et al., 2018, href="#bib35" rid="bib35" class=" bibr popnode">Sun et al., 2016, href="#bib24" rid="bib24" class=" bibr popnode">Meng et al., 2017, href="#bib19" rid="bib19" class=" bibr popnode">Li et al., 2009, href="#bib7" rid="bib7" class=" bibr popnode">Cheng et al., 2013); however, the preparation of 1D perovskites with multi-doping of A-sites and B-sites at large scale is still a great challenge. At present, only a few synthesis methods of 1D ABO3 perovskites are reported, which mainly focus on the preparation of A-sites or B-sites as a single element, such as solvothermal method (href="#bib52" rid="bib52" class=" bibr popnode">Zhai et al., 2018), hydrothermal method (href="#bib25" rid="bib25" class=" bibr popnode">Nakayama et al., 2007), reprecipitation method (href="#bib35" rid="bib35" class=" bibr popnode">Sun et al., 2016), sol-gel method (href="#bib24" rid="bib24" class=" bibr popnode">Meng et al., 2017), and molten salt method (href="#bib19" rid="bib19" class=" bibr popnode">Li et al., 2009, href="#bib7" rid="bib7" class=" bibr popnode">Cheng et al., 2013), whereas it is difficult to control the multicomponent composition of perovskites at A-sites and B-sites with these methods.Perovskite niobate is considered as one of the most competitive lead-free materials to replace lead-bearing perovskite because of its excellent piezoelectric and ferroelectric properties and suitable Curie temperature (href="#bib34" rid="bib34" class=" bibr popnode">Saito et al., 2004, href="#bib54" rid="bib54" class=" bibr popnode">Zhang et al., 2018a, href="#bib55" rid="bib55" class=" bibr popnode">Zhang et al., 2018b, href="#bib44" rid="bib44" class=" bibr popnode">Xu et al., 2016). Herein, we proposed a simple two-step method to synthesize 1D perovskite-type niobate based on a kind of Multi-element Topochemical-Molten Salt (MTMS) method. The key to this approach was that, using 1D anisotropic non-perovskite-type niobate with multi-“B-sites” element as template, large quantities of 1D morphology of perovskite materials at the boundary of quasi-isomorphic phase with controlling multi-doping A-sites and B-sites could be achieved. Accordingly, for the first time, we synthesized the rod-like K2(Nb0.94Sb0.06)8O21 and proposed the mechanism of its derivation into perovskite-type multicomponent niobate products. Furthermore, flexible piezoelectric device (FPD) with planar orientation of rod-like product was prepared. At the same degree of bending, the output voltage was nearly 600% compared with that of the granular material of similar component. This strategy could be extended to the synthesis of large-scale other 1D multi-perovskite materials, which were expected to be widely used in flexible electronics, sensor devices, and energy storage.