Well-aligned ultralong ZnO nanorod arrays with a length of 10 microm have been synthesized on glass substrates using a preheating hydrothermal method. The diameter of the nanorods is in the range from 50 to 80 nm, and the aspect ratio and alignment can be simply controlled by varying the preheating time. Based on the evolution of aspect ratio with preheating time, a possible growth mechanism was proposed. X-ray diffraction (XRD) and scanning electron microscopy (SEM) show that the nanostructures are well oriented with the c-axis perpendicular to the substrate. The photoluminescence (PL) spectrum of the as-grown ZnO nanostructure reveals a near-band-edge (NBE) emission peak and a yellow emission, and the origin of yellow emission was confirmed to be from the absorbed hydroxyl group. The ultralong nanorod arrays made in solution have a desirable diameter, length, density and orientation for ordered nanodevice applications.

A high-performance electrochromic-energy storage device (EESD) is developed, which successfully realizes the multifunctional combination of electrochromism and energy storage by constructing tungsten trioxide monohydrate (WO·HO) nanosheets and Prussian white (PW) film as asymmetric electrodes. The EESD presents excellent electrochromic properties of broad optical modulation (61.7%), ultrafast response speed (1.84/1.95 s), and great coloration efficiency (139.4 cm C). In particular, remarkable cyclic stability (sustaining 82.5% of its initial optical modulation after 2500 cycles as an electrochromic device, almost fully maintaining its capacitance after 1000 cycles as an energy storage device) is achieved. The EESD is also able to visually detect the energy storage level via reversible and fast color changes. Moreover, the EESD can be combined with commercial solar cells to constitute an intelligent operating system in the architectures, which would realize the adjustment of indoor sunlight and the improvement of physical comfort totally by the rational utilization of solar energy without additional electricity. Besides, a scaled-up EESD (10 × 11 cm) is further fabricated as a prototype. Such promising EESD shows huge potential in practically serving as electrochromic smart windows and energy storage devices.

A transparent resistance random access memory (RRAM) structure consisted of all-ZnO-based film is fabricated by the pulsed laser deposition method at room temperature. The device is based on transparent Mg-doped ZnO films, sandwiched by Al-doped ZnO as electrodes. Reliable and reproducible bipolar resistance memory switching performances are achieved. Fast and stable switching behaviour in the voltage pulse mode is demonstrated with set and reset durations of 50 ns and 100 ns, respectively. The transmittance of the device is from 64% to 82% in the visible region. All-ZnO-based transparent RRAM will open a route towards see-through memory devices.

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A noncrystalline, low-resistance La 0.7 Ca 0.3 MnO 3 (LCMO) thin film was deposited by pulsed laser deposition at the substrate temperature of 550 • C and the oxygen pressure of 1 Pa. The low resistance of the resultant film was derived from the large leakage current due to the noncrystallinity of the LCMO film. Ag, Al and Ag-50%Al alloy metals were selected as top electrodes (TEs) on the LCMO film with a Pt bottom electrode to form Ag, Al, Ag-50%Al/LCMO/Pt multilayer units. It was found that stable bipolar resistive switching was only obtained in Al-50%Ag/LCMO/Pt units. Obvious hysteresis and 'current leaps' phenomena occurred clearly in I-V curves of high original resistance units with an Al-50%Ag TE. The low original resistance units can be turned to high resistance by a voltage sweep. Based on these results, a model was proposed to explain the switching properties of the Al-50%Ag/LCMO/Pt units, which will be helpful to improve the switching uniformity of RRAM devices.

Thin films of Ca1-x Sr x CuO2 have been grown by alternate deposition of Ca1-x Sr x and CuO2 atomic layers in a low pressure NO2 ambient. X-ray diffraction and its intensity analysis have confirmed the formation of an infinite layer structure of Ca1-x Sr x CuO2 with x=0.2-1.0. The lattice constant c and electrical conductivity increase systematically with increasing Sr/Ca ratio. Clear diamagnetic signals at 90 K and 120 K have been observed in SrCuO2 and Ca0.2Sr0.8CuO2 films, respectively. In the Ca0.2Sr0.8CuO2 films, the onset of a small diamagnetic signal and a resistivity drop are also observed around 180 K.