Well-aligned, high-resolution (10 nm), three-dimensional (3D) hybrid nanostructures consisting of patterned cylinders and Au islands were fabricated on ITO substrates using an ion bombardment process ...and a tilted deposition process. The fabricated 3D hybrid nanostructure-embedded ITO maintained its excellent electrical and optical properties after applying a surface-structuring process. The solution processable organic photovoltaic device (SP-OPV) employing a 3D hybrid nanostructure-embedded ITO as the anode displayed a 10% enhancement in the photovoltaic performance compared to the photovoltaic device prepared using a flat ITO electrode, due to the improved charge collection (extraction and transport) efficiency as well as light absorbance by the photo-active layer.
A photovoltaic device was successfully grown solely based on the single ZnO p-n homojunction nanowire. The ZnO nanowire p-n diode consists of an as-grown n-type segment and an in situ arsenic-doped ...p-type segment. This p-n homojunction acts as a good photovoltaic cell, producing a photocurrent almost 45 times larger than the dark current under reverse-biased conditions. Our results demonstrate that the present ZnO p-n homojunction nanowire can be used as a self-powered ultraviolet photodetector as well as a photovoltaic cell, which can also be used as an ultralow electrical power source for nanoscale electronic, optoelectronic and medical devices.
Finding suitable electrode materials is one of the challenges for the commercialization of a sodium ion battery due to its pulverization accompanied by high volume expansion upon sodiation. Here, ...copper sulfide is suggested as a superior electrode material with high capacity, high rate, and long‐term cyclability owing to its unique conversion reaction mechanism that is pulverization‐tolerant and thus induces the capacity recovery. Such a desirable consequence comes from the combined effect among formation of stable grain boundaries, semi‐coherent boundaries, and solid‐electrolyte interphase layers. The characteristics enable high cyclic stability of a copper sulfide electrode without any need of size and morphological optimization. This work provides a key finding on high‐performance conversion reaction based electrode materials for sodium ion batteries.
Pulverization‐tolerance and the capacity recovery in CuS enable its outstanding cyclic stability without any size or morphological optimization. Semi‐coherent interfaces in conversion reaction relieves sodium insertion‐induced stress by forming stable grain and phase boundaries rather than random pulverization. Generated grain boundaries enlarge active surface area for sodium insertion and extraction for the capacity recovery.
Lithium‐ion batteries (LIBs) are rechargeable batteries that have attracted great interest as next‐generation energy storage devices that will lead future energy technologies because of their various ...excellent advantages. Two‐dimensional (2D) MXene‐based LIBs have been actively investigated because of their high energy/power density and good performance at high charge/discharge rates. However, three major limitations of 2D MXene electrodes – self‐stacking, low specific surface area, and disturbance of Li+ diffusion by surface terminations – have hindered the commercialization of MXene‐based LIBs. Herein, we fabricate 1D hollow Ti3C2Tx MXene/carbon (MX/C) nanofibers via an electrospinning process and use them as anode materials in LIBs. Compared with the pristine 2D MXene (MX) paste electrode and MXene/carbon (MX/C) paste electrode, the hollow MX/C nanofibers electrode exhibits a greater specific surface area, less self‐stacking of flakes, and surface functional groups tailored for LIBs. The LIBs based on the hollow electrode exhibit a higher energy density (306.5 mA h g−1 at 40 mA g−1) than those with the MX paste electrode (81.08 mA h g−1 at 40 mA g−1) and MX/C paste electrode (196.9 mA h g−1 at 40 mA g−1). In addition, the hollow MX/C nanofiber electrode shows a high reversible capacity, proving that it is a promising anode material for LIBs.
In a spin: One‐dimensional hollow Ti3C2Tx MXene/carbon nanofibers are obtained by utilizing a electrospinning process. The hollow MX/C nanofibers with tailored surface terminations and an increased specific surface area show improved electrochemical performance in binder‐free Li‐ion batteries.
Herein, we report a facile synthesis of high‐density anatase‐phase vertically aligned thornbush‐like TiO2 nanowires (TBWs) on transparent conducting oxide glasses. Morphologically controllable TBW ...arrays of 9 μm in length are generated through a one‐step hydrothermal reaction at 200 °C over 11 h using potassium titanium oxide oxalate dehydrate, diethylene glycol (DEG), and water. The TBWs consist of a large number of nanoplates or nanorods, as confirmed by SEM and TEM imaging. The morphologies of TBWs are controllable by adjusting DEG/water ratios. TBW diameters gradually decrease from 600 (TBW600) to 400 (TBW400) to 200 nm (TBW200) and morphologies change from nanoplates to nanorods with an increase in DEG content. TBWs are utilized as photoanodes for quasi‐solid‐state dye‐sensitized solar cells (qssDSSCs) and solid‐state DSSCs (ssDSSCs). The energy‐conversion efficiency of qssDSSCs is in the order: TBW200 (5.2 %)>TBW400 (4.5 %)>TBW600 (3.4 %). These results can be attributed to the different surface areas, light‐scattering effects, and charge transport rates, as confirmed by dye‐loading measurements, reflectance spectroscopy, and incident photon‐to‐electron conversion efficiency and intensity‐modulated photovoltage spectroscopy/intensity‐modulated photocurrent spectroscopy analyses. TBW200 is further treated with a graft‐copolymer‐directed organized mesoporous TiO2 to increase the surface area and interconnectivity of TBWs. As a result, the energy‐conversion efficiency of the ssDSSC increases to 6.7 % at 100 mW cm−2, which is among the highest values for N719‐dye‐based ssDSSCs.
There′s something good behind the thorn: High‐density anatase‐phase vertically aligned thornbush‐like TiO2 nanowires on transparent conducting oxide (TCO) glasses result in high‐efficiency solid‐state dye‐sensitized solar cells, which exhibits one of the highest values observed for N719 dyes. This can be attributed to improved surface areas, light‐scattering effects, and charge transport rates.
Thin films of well‐stacked two‐dimensional MXene flakes have been used in various applications, especially in sensors and microscale energy storage devices, such as micro‐supercapacitors. ...Miniaturization and integration of devices, as well as maximization of device performance require nanoscale patterning of MXene, beyond what can be achieved using inkjet or screen printing. However, nanoscale patterning technology for MXene is yet to be developed. In the present work, a simple fabrication method is demonstrated for manufacturing Ti3C2Tx MXene films with vertically aligned nanopatterns via soft lithography. This process involves polydimethylsiloxane (PDMS) stamping with line‐patterned PDMS molds. The feature size of the vertical line patterning of MXene is controlled with the nanometers accuracy by swelling of the PDMS mold by toluene, which also guides vertical alignment of MXene flakes. As a result, vertically aligned MXene nanopatterns are fabricated with a width of ridges less than 200 nm and 2‐µm regular spacing between the ridges. The oleylamine‐functionalized MXene flakes are also developed for better dispersion in toluene, providing a general protocol to fabricate MXene dispersions in nonpolar solvents.
A simple and comprehensive method for fabricating nanopatterns with vertical alignment of Ti3C2Tx MXene flakes is demonstrated. The feature size of the vertical patterning is controlled with the nanometers accuracy by swelling of the polydimethylsiloxane mold by toluene. The oleylamine‐functionalized MXene is developed for better dispersion in toluene, providing a general protocol to fabricate MXene dispersions in nonpolar solvents.
We report a high energy conversion efficiency of 8.4% at 100 mW cm super(-2), which is one of the highest values for N719-based, solid-state, dye-sensitized solar cells (ssDSSCs). Our solar cells are ...based on one-dimensional (1D) hierarchical hetero-nanotubes consisting of Au cores and SnO sub(2)/TiO sub(2) nanosheet double shells (referred to as Au SnO sub(2)TNSs). Carbonaceous nanofibers (CNFs) with tellurium (Te) cores are used as dual templates for the inner-deposition of gold and the outer-deposition of the metal oxide layers. An organized mesoporous TiO sub(2) (OM-T) film, with high porosity, large pores, and good interconnectivity, is also prepared viaa graft copolymer template approach and utilized as a matrix to disperse the 1D hierarchical nanostructures. Such nanostructures provide good pore-filling for solid electrolytes, faster electron transfer, and enhanced light scattering, as confirmed by reflectance spectroscopy, incident photon-to-electron conversion efficiency (IPCE) spectroscopy, and intensity-modulated photocurrent spectroscopy (IMPS)/intensity-modulated photovoltage spectroscopy (IMVS).
Triangular silver nanoplates (Ag-NPs) were synthesized using a rapid and reproducible chemical reduction method involving both seeded growth and the selective adhesion of capping ligands. The average ...edge length of the nanoplates and the position of the plasmon resonance band could be tuned over a wide range by simply adjusting the experimental conditions. Using the appropriate seed volume in the growth solution and molar ratio of the capping ligand PVP to the precursor AgNO
3
were found to be indispensable for forming uniform silver nanoplates. Specifically, testing the molar ratio of PVP to AgNO
3
yielded thin nanoplates with edge lengths up to 310 nm, and hence a high aspect ratio. Nanoplates prepared with different seed volumes and PVP-to-AgNO
3
molar ratios were structurally characterized. In addition, the changes in the edge length and size of the Ag nanoplates were studied. The main UV-visible absorption peak of the nanoplate solution showed a blue shift of the surface plasmon band when the seed volume was increased, and a red shift when the molar ratio was increased. The catalytic performance of the synthesized Ag-NPs toward the reduction of the dye rhodamine B (Rh B) by NaBH
4
was established, and the degradation reaction was observed to follow first-order kinetics.
Thin silver nanoplates were found to display superior catalytic activity for the reduction of Rh B.
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