A solution-phase route has been developed for the synthesis of single-crystal CuO nanoribbons with widths of 10-80 nm, thicknesses of 5-20 nm, and lengths ranging from several hundred nanometers to several micrometers and for nanorings with diameters of 100-300 nm. The CuO nanoribbons and nanorings were fabricated by the reaction of CuCl 2 and NaOH solutions with sodium dodecyl benzenesulfonate (SDBS). The as-synthesized products were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM), revealing that CuO nanoribbons and nanorings had single-crystal monoclinic structures and nanorings were closed but were not the simple superposition of two ends of the nanoribbons. On the basis of TEM observations, the formation processes of nanoribbons and nanorings can be interpreted by two stages: initial nanoflakes split into nanoribbons due to the Brownian movement of surfactant molecules, and then these nanoribbons that possess polar surfaces coil into nanorings to reduce the electrostatic energy. This ringlike CuO nanomaterial may have some potential value in nanoscale applications.

Zinc blende-structured CdTe nanoribbons (NRs) were synthesized for the first time via a two-step process. The electronic, transport, and photoconductive properties of the CdTe NRs were studied systematically. It was revealed that the CdTe NRs showed p-type conductivity, and presented significant photoresponses to visible-NIR (400-800 nm) irradiation with high responsivity and gain. The contribution of the factors such as surface states of NRs, channel length, light intensity, and working bias voltage to the photoresponse characteristics of CdTe NR photodetectors were discussed. Moreover, single CdTe NR-based visible-NIR photodetectors were also demonstrated to have high stability and reliability.

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Polymorph discrimination of CaCO3 mineral has been easily realized in an ethanol/water mixed solution system under mild conditions without using any organic additives. The phase transition from a mixture of calcite and aragonite to pure aragonite, and then to almost pure vaterite, can be nicely captured by the choice of a suitable ratio of ethanol to distilled water in the present reaction system. In addition, a complex self-assembly process for the formation of multilayered vaterite cakes in this binary solution system has been proposed. The cakelike vaterite crystals with multilayered structures are porous with an average pore size of 24.9 nm. The results demonstrated that such a binary reaction media could provide an alternative and versatile tool for controlling the polymorph and nanostructures of inorganic minerals through manipulating the thermodynamics and kinetics. This study provides an alternative polymorph switching route for CaCO3 mineral without using any additives and can even be scaled up as a green chemistry method for the industrial production of CaCO3 with different polymorphs.