[en] Graphical abstract: - Highlights: • All solution processed perovskite solar cells were realized with Ag nanowires. • ZnO nanoparticles were used as electron transport layer. • The solar cells showed a photovoltaic behavior with efficiency of 9.21%. • Device performance showed negligible difference between forward and reverse scan. - Abstract: In this paper, we reported a low temperature processed planar heterojunction perovskite solar cell employing silver nanowires as the top electrode and ZnO nanoparticles as the electron transport layer. The CH_3NH_3PbI_3 perovskite was grown as the light absorber via two-step spin-coating technique. The as-fabricated perovskite solar cell exhibited the highest power conversion efficiency of 9.21% with short circuit current density of 19.75 mA cm"−"2, open circuit voltage of 1.02, and fill factor value of 0.457. The solar cell's performance showed negligible difference between the forward and reverse bias scan. This work paves a way for realizing low cost solution processable solar cells.

[en] Highlights: • A double-layered graphene/PEDOT:PSS film was fabricated by spray-coating. • A white flexible phosphorescent OLED was fabricated based on this film. • The white flexible OLED presented pure white light emission. • The flexible OLEDs showed a stable white emission during bending test. - Abstract: A double-layered graphene/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) conductive film was prepared, in which the PEDOT:PSS layer was obtained by using spray-coating technique. A flexible white phosphorescent organic light-emitting devices based on the graphene/PEDOT:PSS conductive film was fabricated. Phosphorescent material tris(2-phenylpyridine) iridium (Ir(ppy)₃) and the fluorescent dye 5,6,11,12-tetraphenylnapthacene (Rubrene) were co-doped into 4,4′-N,N′-dicarbazole-biphenyl (CBP) host. N,N′-diphenyl-N,N′-bis(1-naphthyl)-(1,1′-biphenyl)-4,4′-diamine (NPB) and 4,7-diphenyl-1,10-phenanthroline (Bphen) were used as hole-transporting and electron-transporting layer, respectively, and 4,4′-bis(2,2′-diphenylvinyl)-1,1′-biphenyl (DPVBi) was used as blue light-emitting layer. The device presented pure white light emission with a Commission Internationale De I’Eclairage coordinates of (0.31, 0.33) and exhibited an excellent light-emitting stability during the bending cycle test with a radius of curvature of 10 mm

[en] Novel MnO_x@Carbon hybrid nanowires were successfully synthesized by the combination of a hydrothermal process and a simple PVP (polyvinylpyrrolidone) – solution-soaking method followed by a subsequent carbonization treatment. The nanostructures exhibit the unique feature of having nanocrystalline manganese oxide particle encapsulated inside and an amorphous carbon layer coating the outside. The unique porous characteristics with many meso/micro-pores, and further the highly conductive carbon matrix would lead to the excellent electrochemical performance of the MnO_x@Carbon nanowire electrode. The MnO_x@Carbon hybrid nanowires exhibit a high initial reversible capacity of 824.4 mAhg⁻¹, a reversible capacity of approximately 541 mAhg⁻¹ after 54 cycles, and excellent cycling stability and rate capability with specific capacity of 298.24 mAhg⁻¹ when cycled at the current density of 1000 mAg⁻¹, which indicates that the composite is a promising anode candidate for Li-ion batteries. - Highlights: • MnO_x@C composite were obtained by hydrothermal and PVP-solution-soaking method. • The structures is characteristic of MnO_x nanocrystals coated into carbon matrix. • The electrode exhibits good Li⁺ capacities, cycling stability and rate capability

[en] Graphene quantum dots (GQDs), which are edge-bound nanometer-size graphene pieces, have fascinating electronic and optical properties due to their quantum confinement and edge effect. In this paper, GQDs were synthesized by using acid treatment and chemical exfoliation of multi-walled carbon nanotubes (MWCNTs). The structure of the GQDs was investigated by transmission electron microscope. The GQDs have a uniform size distribution, zigzag edge structure and two-dimensional morphology. The results indicated that the GQDs have bright blue emission upon UV excitation. The highly fluorescent GQDs exhibited high water solubility and good stability. It is shown that the acid treatment of MWCNTs leads to the formation of the functional group in zigzag sites, which results in the pH-dependent fluorescence of the GQDs

[en] Different morphologies of comb-like ZnO and oriented ZnO nano-arrays such as ZnO nanoneedles and ZnO nanorods were synthesized by using flexible thermal evaporation method via simply adjusting the temperature and oxygen content. The ZnO nanorods arrays have the lowest turn-on field, highest current density and the largest emission efficiency owning to its good contact with the substrate and relatively weaker field screening effects. The experiments show that the morphologies and orientation of one-dimensional (1D) ZnO nanomaterials have considerable effects on the turn-on field and the emission current density, and the nanoarray also contributes to electrons emission. The results could be valuable for the application of ZnO nanorod arrays as cathode materials in field emission based devices. (semiconductor materials)

[en] Patterned ZnO nanowires were successfully synthesized on ITO electrodes deposited on the glass substrate by using a simple thermal evaporation approach. The morphology, crystallinity and optical properties of ZnO nanowires were characterized by scanning electron microscopy, X-ray diffraction, energy dispersive X-ray and photoluminescence spectroscopy. Their field emission characteristics were also investigated. SEM images showed that the ZnO nanowires, with a diameter of 100–200 nm and length up to 5 μm, were highly uniform and well distributed on the linear ITO electrodes. The field emission measurement indicated that patterned ZnO nanowire arrays have a turn-on field of 1.6 V/μm at current density of 1 μA/cm² and a threshold field of 4.92 V/μm at current density of 1 mA/cm² at an emitter-anode gap of 700 μm. The current density rapidly reached 2.26 mA/cm² at an applied field of 5.38 V/μm. The fluctuation of emission current was lower than 5% for 4.5 h. The low turn-on field, high current density and good stability of patterned ZnO nanowire arrays indicate that it is a promising candidate for field emission application. (semiconductor materials)

[en] Highlights: • Molybdenum oxide (MoOx) as hole injection layer was formed by solution process. • Flexible quantum dot light-emitting diodes with MoOx exhibit superior performance. • Stability/lifetime of the light-emitting devices is substantially improved. -- Abstract: In this paper, the aqueous solution-processed molybdenum oxide (sMoO_x) as an efficient hole injection layer for flexible quantum dot light emitting diodes (QLEDs) was prepared using a simple, low-cost and non-toxic solution method. Compared to the traditional device used poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as hole injection layer, the flexible QLED with modified sMoO_x film has a higher maximum current efficiency, 5.46 cd/A. In addition, the stability and lifetime of flexible devices are improved effectively with the use of inorganic molybdenum oxide as hole injection layer, and they presented excellent flexibility through the repeated mechanical bending test at 5 mm radius of curvature.

[en] One-dimensional CuO nanostructure arrays have been synthesized on Cu foil by a low-temperature wet chemical process. Different CuO nanostructures including nanorods with facet heads, nanorods with needle-like tips and nanotubes are shaped simply by varying the concentration of oxidant. Field emission measurements show that CuO nanorods with needle-like tips are of superior performance than other shapes, having a turn-on field of 3.5V/μm and a field enhancement fact or of 2107. The good field emission performance is assigned to the sharp tips contributing to the high field enhancement effect and to the moderate density reducing the field screening effect. (semiconductor materials)

[en] In this work, we report an all-solution route to produce semi-transparent high efficiency perovskite solar cells (PSCs). Instead of an energy-consuming vacuum process with metal deposition, the top electrode is simply deposited by spray-coating silver nanowires (AgNWs) under room temperature using fabrication conditions and solvents that do not damage or dissolve the underlying PSC. The as-fabricated semi-transparent perovskite solar cell shows a photovoltaic output with dual side illuminations due to the transparency of the AgNWs. With a back cover electrode, the open circuit voltage increases significantly from 1.01 to 1.16 V, yielding high power conversion efficiency from 7.98 to 10.64%. (paper)

[en] A simple CNT/Fe₃O₄ composite electrophoretic deposition method to improve the field emission cathode properties of carbon nanotubes (CNTs) is proposed. It is found that CNT/Fe₃O₄ composite electrophoretic deposition leads to better field emission performance than that of single CNT electrophoretic deposition. The result is investigated using SEM, J-E and FE. After the process, the turn-on electric field decreases from 0.882 to 0.500 V/μm at an emission current density of 0.1 mA/cm², and the latter increases from 0.003 to 1.137 mA/cm² at an electric field of 0.64 V/μm. CNT/Fe₃O₄ composite electrophoretic deposition is an easy and effective cathode preparation for field emission display applications. (semiconductor technology)