Spontaneous Phase Transformation and Exfoliation of Rectangular Single-Crystal Zinc Hydroxy Dodecylsulfate Nanomembranes

Abstract

Free-standing two-dimensional (2D) nanostructures, exemplified by graphene and semiconductor nanomembranes, exhibit exotic electrical and mechanical properties and have great potential in electronic applications where devices need to be flexible or conformal to nonplanar surfaces. Based on our previous development of a substrate-free synthesis of large-area, free-standing zinc hydroxy dodecylsulfate (ZHDS) hexagonal nanomembranes, herein, we report a spontaneous phase transformation of ZHDS nanomembranes under extended reaction time. The hexagonal ZHDS sheets transformed into rectangular single crystal nanomembranes with sizes of hundreds of micrometers. They contain long-range-ordered zinc vacancies that can be fitted into an orthorhombic superlattice. A surplus of dodecylsulfate ions and a deficit of Zn(2+) diffusion near the water surface are believed to be the factors that drive the phase transformation. The phase transformation starts with the formation of zinc vacancies at the topmost layer of the hexagonal hillock, and propagates along the spiral growth path of the initial hexagonal sheets, which bears a great resemblance to the classic "periodic slip process". Mechanical property characterization of ZHDS nanomembranes by nanoindentation shows they behave much like structural polymers mechanically due to the incorporation of surfactant molecules. We also developed a one-step exfoliation and dehydration method that converts ZHDS nanomembranes to ZnO nanosheets using n-butylamine. This work provides a further understanding of the growth and stability of ZnO-based nanomembranes, as well as advisory insight for the further development on solution-based synthesis of free-standing, single-crystalline 2D nanostructures.

Laser-induced fabrication of single crystal zinc hydroxyl dodecylsulfate nano-sheets with excellent fluorescence emission

“…The signals of S, Zn, O, C elements are also detected in the EDS pattern (Fig. The low-angle-XRD (10-20 ) patterns clearly reveal that a series of (001), (002), and (003) ZHDS diffraction peaks centered at 11.037 , 13.240 , and 17.691 were indeed detected, and higher-order diffractions at higher angles (20 -30 ), which agree well with the results obtained by Wang et al 2,3 In order to further conrm the DS functional groups and hydroxy groups (-OH) crystallized in nano-products, the Fourier transforms infrared spectrums (FT-IR) were used to characterize the ZnO and willow leafshaped ZHDS sheets in Fig. Because of the obvious curved surface in the edge regions of willow leaf-shaped ZHDS nano-sheets, the ratio of C to Zn, S, or O is improved to about 8.3 : 0.8 : 0.8 : 3.2.…”

“…[1][2][3][4][5] Compared with organic dyes and polymers, the metallo/organic compounds are generally characterized by additional properties such as high thermal and optical stability and remarkable electron transport and excellent luminescent properties. [1][2][3][4][5] Compared with organic dyes and polymers, the metallo/organic compounds are generally characterized by additional properties such as high thermal and optical stability and remarkable electron transport and excellent luminescent properties.…”

Effects of Piezoelectric Potential of ZnO on Resistive Switching Characteristics of Flexible ZnO/TiO2 Heterojunction Cells

“…The peak centered at 1022.3 eV is the signature peak of Zn 2+ in ZnO, corresponding to the Zn 2p3/2 core level. [21][22][23] Its symmetrical shape indicates a perfect stoichiometry of the sputtering ZnO film (Fig. 1c).…”

Assembly and Self‐Assembly of Nanomembrane Materials—From 2D to 3D

“…Micro/nanoactuators or micro/nanorobots based on nanomembranes have already been fabricated by using this idea, but much future work is still needed to realize overall optimization of the structures that can respond to different stimulations with large forces and high sensitivity, selectivity, and speed . In addition, 2D material nanomembranes have attracted increasing interest . Composite nanomembranes fabricated by stacking 2D nanomaterials and layers of other materials (by, e.g., transfer printing) may represent another important direction of the nanomembrane field.…”