Temperature-Dependent Growth of Ordered ZnO Nanorod Arrays

Ordered ZnO nanorod arrays were epitaxially grown on GaN substrates by a hydrothermal method.The patterned template was made by transferring a self-assembled close-packed monolayer of polystyrene(PS)nanospheres onto GaN substrates.Then magnetron sputtering of SiO_(2)was used to mediate the size of PS nanospheres by plasma etching and form periodic seed sites for the following ZnO growth.It was observed that the size of ZnO nanorods could be varied by changing the temperature of hydrothermal growth,and the relationship between height and diameter of nanorods versus growth temperature was studied.This work provides a potential low-cost hydrothermal method for the preparation of ordered semiconductor nanorod arrays.

420nm thick CH_3NH_3PbI_(3-x)Br_x capping layers for efficient TiO_2 nanorod array perovskite solar cells

The rutile TiO_2 nanorod arrays with 240 nm in length, 30 nm in diameter, and 420 μm^(-2) in areal density were prepared by the hydrothermal method to replace the typical 200-300 nm thick mesoporous TiO_2 thin films in perovskite solar cells. The CH_3NH_3PbI_3-xBrx capping layers with different thicknesses were obtained on the TiO_2 nanorod arrays using different concentration PbI_2·DMSO complex precursor solutions in DMF and the photovoltaic performances of the corresponding solar cells were compared. The perovskite solar cells based on 240 nm long TiO_2 nanorod arrays and 420 nm thick CH_3NH_3PbI_(3-x)Br_x capping layers showed the best photoelectric conversion efficiency(PCE) of 15.56%and the average PCE of 14.93 ± 0.63% at the relative humidity of 50%-54% under the illumination of simulated AM 1.5 sunlight(100 mW·cm^(-2)).

Hydrothermal Synthesis of Ordered ZnO Nanorod Arrays by Nanosphere Lithography Method

Ordered ZnO nanorod arrays were hydrothermally synthesized on a patterned GaN substrate formed by a nanosphere lithography method.Firstly,polystyrene(PS)nanospheres were used to self-assemble a close-packed monolayer on the surface of water.Then the monolayer was transferred onto a GaN substrate.Subsequently,magnetron sputtering of SiO2 was used to reduce the size of PS nanospheres and cover the interstitial space between PS nanospheres by SiO_(2) at the same time.After removing the PS nanospheres,periodic seed sites were accomplished on the GaN substrate for ZnO growth.Finally,ordered ZnO nanorod arrays,perpendicular to the substrate,were grown on GaN substrates by a hydrothermal method.This work provides a potential low-cost hydrothermal method for the preparation of ordered semiconductor nanorod arrays.

Titanium nitride nanorod array/carbon cloth as flexible integrated host for highly stable lithium-sulfur batteries

Lithium-sulfur(Li-S)batteries have been regarded as promising energy-storage systems,due to their high theoretical capacity and energy density.However,the carbonaceous sulfur hosts suffer from weak binding force between the hosts and polysulfides,restricting the cyclic stability of sulfur electrode.Meantime,the presence of binder and conductive agent in the traditional electrode reduces its energy density.This study demonstrates that titanium nitride(TiN)nanorod array on carbon cloth(CC)is employed as a flexible host for highly stable Li-S batteries via solvothermal synthesis-nitridation strategy.On the one hand,the flexible integrated network composed of three-dimensional TiN nanorod array and CC significantly improves the conductivity,increases the electron transport and electrolyte penetration of cathode.On the other hand,the 3D structure of TiN/CC and the enhanced polarity of TiN effectively strengthen the physical and chemical double adsorption for polysulfides.As a result,the combination of TiN nanorod array and CC synergistic ally promotes sulfur utilization and electrochemical performances of S@TiN/CC cathode.A discharge capacity of1015.2 mAh·g^(-1)at 0.5C after 250 cycles and 604.1mAh·g^(-1)at 3C after 250 cycles is realized.Under a larger current density of 5C,the resulting S@TiN/CC cathode maintains a high discharge capacity of 666.6 mAh·g^(-1)and the Coulombic efficiency of about 100%.

Designing TiO_(2)/Au/Prussian blue heterostructures nanorod arrays for ultra-stable cycle and ultra-fast response electrochromism

Prussian blue(PB)is an anodic coloring candidate in the wide area of electrochromic(EC)applications.However,the co-influence of weak adhesion and low electrical conductivity leads to the poor stability and slow switching speed.To tackle this bottleneck,a novel TiO_(2)/Au/PB nanorod array is designed through hydrothermal and electrodeposition approaches on fluorine-doped tin oxide(FTO)glass.Such a designed ternary array structure could not only increase reactive site and conductivity,but also improve ion storage capacity and promote charge transfer,attributed to the synergistic effect of TiO_(2)/Au/PB core–shell heterostructure and the localized surface plasmon resonance(LSPR)effect of Au nanoparticles.Besides,density functional theory(DFT)calculation confirms the strong interaction between rutile TiO_(2)and FTO substrate,which contributes to the improvement of EC cycle stability.Benefiting from these effects,the TiO_(2)/Au/PB film shows a fast coloration/bleaching response of 1.08/2.01 s(2.17/4.48 s,PB film)and ultra-stable EC performance of 86.8%after 20,000 cycles(50%after 600 cycles,PB film).Furthermore,the high-intensity light source can be shot clearly by the designed and assembled EC iris device(ECID)with TiO_(2)/Au/PB film as an EC layer,while the photograph without an ECID is blurry,confirming the feasibility of the material in portable digital products.

Investigation of photoelectrocatalytic degradation mechanism of methylene blue by a-Fe_(2)O_(3) nanorods array

Efficiently and thoroughly degrading organic dyes in wastewater is of great importance and challenge.Herein,vertically oriented mesoporous a-Fe_(2)O_(3)nanorods array(a-Fe_(2)O_(3)-NA)is directly grown on fluorine-doped tin oxide(FTO)glass and employed as the photoanode for photoelectrocatalytic degradation of methylene blue simulated dye wastewater.The Ovsites on the a-Fe_(2)O_(3)-NA surface are the active sites for methylene blue(MB)adsorption.Electrons transfer from the adsorbed MB to Fe-O is detected.Compared with electrocatalytic and photocatalytic degradation processes,the photoelectrocatalytic(PEC)process exhibited the best degrading performance and the largest kinetic constant.Hydroxyl,superoxide free radicals,and photo-generated holes play a jointly leading role in the PEC degradation.A possible degrading pathway is suggested by liquid chromatography-mass spectroscopy analysis.This work demonstrates that photoelectrocatalysis by a-Fe_(2)O_(3)-NA has a remarkable superiority over photocatalysis and electrocatalysis in MB degradation.The in-depth investigation of photoelectrocatalytic degradation mechanism in this study is meaningful for organic wastewater treatment.

One-dimensional Ag2S/ZnS/ZnO nanorod array films for photocathodic protection for 304 stainless steel

Highly ordered Ag2 S/ZnS/ZnO nanorod array film photoanodes were prepared on a Ti substrate for photocathodic cathodic protection.The results indicated that the photoresponse range of the Ag2S/ZnS/ZnO composite film was extended compared to those of the ZnO and ZnS/ZnO films,indicating its higher light absorption capacity.When the Ag2S/ZnS/ZnO composite film served as a photoanode,the film can provide the best effective photocathodic protection for 304 stainless steel in a 3.5 wt%NaCl solution under white light illumination compared to the ZnO and ZnS/ZnO films.Additionally,in comparison to pure ZnO film,the photocurrent for the ZnS/ZnO film remained the same without noticeable fluctuation after illumination for 1 h,indicating that the ZnS functionalization improved the stability by overcoming the photocorrosion effect of the ZnO photoanode under light irradiation.

An amorphous FeMoO_(4) nanorod array enabled high-efficiency oxygen evolution electrocatalysis in alkaline seawater

The development of highly efficient and durable oxygen evolution reaction(OER)catalysts for seawater electrolysis is of great importance for applications.Here,an amorphous FeMoO_(4) nanorod array on Ni foam is reported as a highly active OER electrocatalyst in alkaline seawater,requiring only overpotentials of 303 and 332 mV to achieve 100 and 300 mA·cm^(-2),respectively.Moreover,it shows strong long-term electrochemical durability for at least 50 h.

An orderly arranged dual-role MIL-53(Al)nanorods array rooted on carbon nanotube film for long-life and stable lithium-sulfur batteries

It is of great value to synchronously resolve the critical issues of the polysulfide shuttle and dendrite growth in lithium-sulfur(Li-S)batteries.Herein,a bifunctional Al-based Material of Institute Lavoisier-53(MIL-53(Al))/carbon nanotube(MIL-53/CNT)composite is reported for this matter,which was constructed by growing an ordered MIL-53(Al)nanorods array on the CNT film.For the sulfur cathode,the proposed structure serves as a multifunctional interlayer to block polysulfides and accelerate their catalytic conversion,thus efficaciously inhibiting the shuttle effect.Meanwhile,when applied as the anode host material(Li@MIL-53/CNT),the flexible CNT film serves as a self-standing framework to accommodate Li metal and alleviate the volume expansion,while the uniform ion channels built by the MIL-53(Al)nanorods array along with the abundant oxygen groups can homogenize Li ion diffusion,enabling a steady Li plating/stripping behavior and limiting the dendrite growth.Not surprisingly,Li-S full battery with MIL-53/CNT interlayer and Li@MIL-53/CNT anode delivers an appreciable specific capacity of 735 mAh·g^(–1)and excellent cycle durability at 5 C,presenting a limited capacity decay of 0.03%per cycle in 500 cycles.Besides,an impressive cycle stability and rate capability are also achieved at high-sulfur loading and lean electrolyte conditions.