Hybrid Structure Of Nanoparticles Research Articles

Surface plasmon resonance induced enhancement of photoluminescence and Raman line intensity in SnS quantum dot-Sn nanoparticle hybrid structure

In this article, we report on enhancement in photoluminescence and Raman line intensity of SnS quantum dots embedded in a mesh of Sn nanostructures. SnS nanoparticles synthesized by homogenous precipitation method show strong quantum confinement with a band gap of ∼2.7 eV (blue shift of ∼1 eV compared to bulk SnS particles). The optical band gap of SnS quantum dots is controlled by varying the pH (∼0 to 2.25), ageing time (24 to 144 h) and molarity (0 to 2 M) of the precursors. These SnS nanoparticles are embedded in a mesh of Sn nanostructures which are synthesized from tin chloride by using sodium borohydride as reducing agent. The Sn nanostructures have a morphology dependent, tunable surface plasmon resonance (SPR), ranging from UV (∼295 nm) to visible region (∼400 nm) of the electromagnetic spectrum. In the SnS-Sn nanohybrids, the excitons are strongly coupled with plasmons leading to a shift in the excitonic binding energy (∼400 meV). The pure SnS quantum dots have a very weak photoluminescence peak at ∼560 nm and Raman shift of low intensity at 853.08 cm−1, 1078.17 cm−1, 1255.60 cm−1, 1466.91 cm−1. The coupling of SnS nanoparticles with Sn nanoparticles results in strong exciton-plasmon interactions leading to enhanced photoluminescence and Raman line intensity. The nanohybrids formed using Sn nanosheets whose SPR matches with absorption onset of the SnS nanoparticles shows an enhancement of ∼104 times higher than pure SnS nanoparticles. Thus, Sn nanosheet with surface plasmon resonance in visible region (400 nm) like Au and Ag is a promising material for surface enhanced Raman spectroscopy, plasmon assisted fluorescence imaging and for enhancing the emission intensity of semiconductors with weak emission intensity.

In situ promoting water dissociation kinetic of Co based electrocatalyst for unprecedentedly enhanced hydrogen evolution reaction in alkaline media

Carbon-encapsulated 3d-transition metal (TM) hybrid structure (denoted as M@C) have been considered as a promising candidate for HER. In recent years, the Co@C composites have exhibited effective HER catalytic performance in acidic media. However, the catalytic performance of Co@C in alkaline media is still unsatisfactory because of the sluggish water dissociation in Volmer step. In this work, by using carbon encapsulated metal Co nanoparticles hybrid structure (CoNP@C) as precatalyst, we firstly demonstrate that the HER activity of Co-based precatalysts could be unprecedentedly promoted through a simple in situ electrochemical activation process. Compared with initial CoNPs@C precatalyst, the activated catalyst realizes about 3.5-fold improved activity and the overpotential greatly decreases from 191 mV to 58 mV at 10 mA cm−2. Specially, the remarkable reduced Tafel slope (from 113 mV dec−1 to 51 mV dec−1) indicates that the sluggish kinetics of the water dissociation step (Volmer step) is effectively speeded up by in situ electrochemical activation. Such a highly enhanced catalytic performance is mainly due to the in situ introduction of cobalt hydroxides NPs as water dissociation promoter and the synergetic effects among core Co NPs, middle layered carbon structure and outer cobalt hydroxides NPs. Our study offers a generic strategy for development of high-performance 3d-transition metal hybrid based HER catalysts in alkaline media.

Sn-Nanorod-Supported Ag Nanoparticles as Efficient Catalysts for Electroless Deposition of Cu Conductive Tracks

The applications of tin are extremely wide-ranging, in fields as diverse as Li-ion batteries, catalysis, and electronic packaging. It is always significant but still remains a great challenge to develop facile and efficient routes to synthesize Sn nanostructures. Herein, we report a facile chemical method to synthesize a Sn nanorod crystal at room temperature, and Ag ions are subsequently introduced to form the Sn-nanorod-supported Ag nanoparticles hybrid structure (Sn/Ag nanorods). The Sn/Ag nanorods exhibit comparable activity to the commercial Pd black in catalyzing the electroless copper deposition (ECD) reaction that is indispensable to fabricate printed circuit boards (PCBs). Furthermore, a screen printable adhesive is prepared by mixing the as-synthesized Sn/Ag nanorod powders and epoxy resin to fabricate activator patterns on epoxy laminate (EPL) and flexible substrates including polyethylene terephthalate (PET) and polytetrafluoroethylene (PTFE) fiber film. The printed areas are finally metalized...

Well Controlling of Plasmonic Features of Gold Nanoparticles on Macro Porous Silicon Substrate by HF Acid Concentration

In this work, we fabricated an efficient macroporous silicon/gold nanoparticles (macro psi/AuNPs) hybrid structure and how well controlling of plasmonic features on macro psi/AuNPs employs them for highly sensitive detection of the very low concentration of cyanine (Cy) dyes molecules. Macro-PSi was synthesized on n-type Si wafer with 3–10 Ω. cm resistivity and 100 orientation using Photo Electro Chemical Etching (PECE) process with630 nm illumination wavelength and 30 mW/cm2 illumination intensity. The macroPSi /AuNPs hybrid structure substrates were prepared by simple and quick dipping process of macroPSi in tetrachloroauric gold solution HAuCl4 with different concentrations of (10−2 M, 10−2 M diluted in 2.9 M of HF, 5 × 10−3 M, and 5 × 10−3 M diluted in 2.9 M of HF). Efficient surface-enhanced Raman scattering (SERS) signals was obtained from macroPSi/AuNPs substrates for Cy dye concentration of about 10−6 and 10−10 M. The detection method is dependent on a nanoparticles sizes process through controlling the concentration in a HAuCl4 solution. Higher SERS signal was found for sample with lower salt concentration of 5 × 10−3 M diluted in HF. The enhancement factors (EF) of Raman’s signal increased four orders of magnitude by diluting the salt concentration. The values of EF in the range of 0.8 × 103−0.72 × 107 were obtained by controlling the salt concentration from 10−2 to 5 × 10−3 diluted in HF acid.

Reduced Graphene oxide / Nanoparticle hybrid structures: A new generation smart materials for optical sensors

Graphene oxide/reduced Graphene oxide hybrid nanomaterials have been widely used as substrates for surface enhanced Raman spectroscopy. This is mainly due to that they have unique structures and inherent properties including highest specific surface area, chemical and electrochemical inertness and easy surface modification etc. It is the parent of all graphite form and is an interesting topic of research in the last three to four years. It can be stacked to form 3D graphite, rolled to form ID nanotubes and wrapped to form 0D fullerenes. The long-range π-conjugation in graphene shows extraordinary thermal, mechanical and electrical properties. The carbon nanomaterial-based spectroscopy detection of chemical and biological molecules has gained much attention with its extensive applications to genomic, proteomic and environmental analysis as well as for clinical diagnosis.Surface enhanced Raman (SERS) spectroscopyhas proven to be an effective technique for analyzing the innovative nanomaterials, graphene. This technique has also helped in identifying some unique properties ofgrapheneas a Raman substrate for the suppression of fluorescence. The requirement for a substrate that is biocompatible, chemically inert, and capable of Raman enhancement is a major technological objective and grapheneserves as a suitable material.

Interface Engineering with MoS2 -Pd Nanoparticles Hybrid Structure for a Low Voltage Resistive Switching Memory.

Metal oxide-based resistive random access memory (RRAM) has attracted a lot of attention for its scalability, temperature robustness, and potential to achieve machine learning. However, a thick oxide layer results in relatively high program voltage while a thin one causes large leakage current and a small window. Owing to these fundamental limitations, by optimizing the oxide layer itself a novel interface engineering idea is proposed to reduce the programming voltage, increase the uniformity and on/off ratio. According to this idea, a molybdenum disulfide (MoS2 )-palladium nanoparticles hybrid structure is used to engineer the oxide/electrode interface of hafnium oxide (HfOx )-based RRAM. Through its interface engineering, the set voltage can be greatly lowered (from -3.5 to -0.8 V) with better uniformity under a relatively thick HfOx layer (≈15 nm), and a 30 times improvement of the memory window can be obtained. Moreover, due to the atomic thickness of MoS2 film and high transmittance of ITO, the proposed RRAM exhibits high transparency in visible light. As the proposed interface-engineering RRAM exhibits good transparency, low SET voltage, and a large resistive switching window, it has huge potential in data storage in transparent circuits and wearable electronics with relatively low supply voltage.

Plasmonically enhanced lasing by different size silver nanoparticles-silver film hybrid structure

Abstract We reported on the enhanced lasing in organic dyes based on plasmonic hybrid structure of Ag nanoparticles (NPs)-Ag film, the diameters of Ag NPs ranged from 20 nm to 100 nm. The lowest lasing threshold was achieved by the optimal size Ag NPs-Ag film hybrid structure, which was reduced by 5.2 times than that of the neat gain medium. Comparing to the separate Ag NPs or Ag film, the hybrid structure presented the more intense local electric field due to the plasmonics coupling between the localized surface plasmons of Ag NPs and the surface plasmon polariton of Ag film, and the stronger scattering due to the reinjection of the leaking photons by external feedback of Ag film. The effects of different sizes Ag NPs-Ag film hybrid structures on lasing were investigated. It found that when the Ag NPs in hybrid structure is small (diameter≤40 nm), the enhanced localized electric field plays a major role on enhanced lasing; with the increase of Ag NPs size, the enhanced electric field and scattering have comparable contribution on enhancing lasing; for the larger size Ag NPs-Ag film (diameter≥80 nm), the scattering effect is the dominant mechanism for random lasing. Then the lowest threshold was dominated by the balance of enhanced localized electric field and scattering effect. Our results could provide us a unique idea to effectively enhance the lasing of organic dyes, and realize the lower pumped threshold and stronger lasing.

Gold nanoparticle mediated graphene plasmon for broadband enhanced infrared spectroscopy

Graphene plasmonics, with dynamic tunable resonance wavelength, has been successfully used in broadband plasmon-enhanced infrared spectroscopy. However, the requirement for external voltage loading makes the practical application sophisticated. In this work, the hybrid structure of graphene nanodot array (GNA) and gold nanoparticles (AuNPs) has been proposed as a passive platform for broadband infrared absorption enhancement. Numerical simulations show that the plasmon resonance peak of GNA becomes stiffer and broader when introducing AuNPs, and this is also proved by experimental results that the vibrational modes of polyethylene oxide molecule in a broad spectral range can be simultaneously enhanced. The metal-graphene hybrid plasmonic system has been proved to be a promising candidate for infrared sensing, which is significant for safety and healthy applications.

A novel U-bent plastic optical fibre local surface plasmon resonance sensor based on a graphene and silver nanoparticle hybrid structure

In this work, we have presented a novel local surface plasmon resonance (LSPR) sensor based on the U-bent plastic optical fibre (U-POF). Firstly, a layer of discontinuous silver (Ag) thin film was deposited on the U-POF and then the Ag film was covered by a layer of cladding synthesized by polyvinyl alcohol (PVA), graphene and silver nanoparticles forming the PVA/G/AgNPs@Ag film. The normalized transmittance spectrum of the LSPR sensor have been collected in a range of the refractive index (RI) from 1.330 to 1.3657 in ethanol solution, and 700.3 nm/RIU sensitivity of the developed LSPR sensor has been demonstrated. By experiments, we demonstrated that the graphene could improve the sensitivity of the LSPR sensor and delay the oxidation process of the AgNPs effectively to keep the stability of the LSPR sensor. The LSPR sensor also exhibited good sensitivity and linearity in the detection of glucose solutions. This work shows that the developed LSPR sensor may have promising applications in biosensing.

A stretchable crumpled graphene photodetector with plasmonically enhanced photoresponsivity.

Graphene has been widely explored for flexible, high-performance photodetectors due to its exceptional mechanical strength, broadband absorption, and high carrier mobility. However, the low stretchability and limited photoabsorption of graphene have restricted its applications in flexible and highly sensitive photodetection systems. Various hybrid systems based on photonic or plasmonic nanostructures have been introduced to improve the limited photoresponsivity of graphene photodetectors. In most cases, the hybrid systems succeeded in the enhancement of photoresponsivity, but showed limited mechanical stretchability. Here, we demonstrate a stretchable photodetector based on a crumpled graphene-gold nanoparticle (AuNP) hybrid structure with ∼1200% enhanced photoresponsivity, compared to a conventional flat graphene-only photodetector, and exceptional mechanical stretchability up to a 200% tensile strain. We achieve plasmonically enhanced photoresponsivity by integrating AuNPs with graphene. By crumpling the hybrid structure, we realize mechanical stretchability and further enhancement of the optical absorption by densification. We also demonstrate that our highly stretchable photodetector with enhanced photoresponsivity can be integrated on a contact lens and a spring structure. We believe that our stretchable, high performance graphene photodetector can find broad applications for conformable and flexible optical sensors and dynamic mechanical strain sensors.

Vertically aligned Pt nanowire array/Au nanoparticle hybrid structure as highly sensitive amperometric biosensors

In recent years, vertically aligned nanowires have been investigated in a range of sensor development for high sensitivity and selectivity detection. In this research, a novel 3D hybrid structure based on vertically aligned Pt nanowire array (PtNWA) coated with Au nanoparticles has been developed as highly sensitive electrochemical biosensors. The vertical Pt nanowire array has been prepared by an electrodeposition method within anodic aluminum oxide (AAO) membranes; then a controllable electroless plating procedure was applied to deposit Au nanoparticles uniformly onto the surface of the Pt nanowires. Finally, glucose oxidase (GOD) enzyme was immobilized on the surface of Au nanoparticles with two widely used enzyme immobilization methods (1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS) crosslinking and glutaraldehyde crosslinking). This nanowire/nanoparticle hybrid structure resulted in higher density of Au nanoparticles than traditional 2D planar electrode modification method. The high density of Au nanoparticles could significantly increase the density of glucose oxidase enzyme immobilized, resulting in better sensing ability. The electron transfer could be enhanced by the 3D vertically aligned Pt nanowire array, leading to higher signal to noise ratio. The electrochemical performances under two different enzyme immobilization methods were studied. The results showed that the PtNWA/AuNPs/GOD sensor exhibited a sensitivity of 184μAmM−1cm−2, a limit of detection of 15μM, and high selectivity toward the detection of glucose, by using the EDC/NHS immobilization method. The storability and real sample tests have also been investigated. This novel nanowire array/nanoparticle hybrid structure, with appropriate enzyme immobilization, can be used as a platform for quantitative measurements of a variety of biomolecules.

Monitoring the electrochemical responses of neurotransmitters through localized surface plasmon resonance using nanohole array

In this study, a novel spectroelectrochemical method was proposed for neurotransmitters detection. The central sensing device was a hybrid structure of nanohole array and gold nanoparticles, which demonstrated good conductivity and high localized surface plasmon resonance (LSPR) sensitivity. By utilizing such specially-designed nanoplasmonic sensor as working electrode, both electrical and spectral responses on the surface of the sensor could be simultaneously detected during the electrochemical process. Cyclic voltammetry was implemented to activate the oxidation and recovery of dopamine and serotonin, while transmission spectrum measurement was carried out to synchronously record to LSPR responses of the nanoplasmonic sensor. Coupling with electrochemistry, LSPR results indicated good integrity and linearity, along with promising accuracy in qualitative and quantitative detection even for mixed solution and in brain tissue homogenates. Also, the detection results of other negatively-charged neurotransmitters like acetylcholine demonstrated the selectivity of our detection method for transmitters with positive charge. When compared with traditional electrochemical signals, LSPR signals provided better signal-to-noise ratio and lower detection limits, along with immunity against interference factors like ascorbic acid. Taking the advantages of such robustness, the coupled detection method was proved to be a promising platform for point-of-care testing for neurotransmitters.

Size-controlled preparation of peroxidase-like graphene-gold nanoparticle hybrids for the visible detection of norovirus-like particles

A hybrid structure of graphene-gold nanoparticles (Grp-Au NPs) was designed as a new nanoprobe for colorimetric immunoassays. This hybrid structure was prepared using chloroauric acid, sodium formate and Grp flakes at room temperature. Au NPs attached strongly onto the Grp surface, and their size was controlled by varying the sodium formate concentration. The Raman intensity of the Grp-Au NP hybrids was significantly enhanced at 1567cm−1 and 2730cm−1 compared with those of pristine Grp because of the electronic interaction between Au NPs and Grp. The Grp-Au NPs with a hybrid structure catalyzed the oxidation of the peroxidase substrate 3,3,5,5-tetramethylbenzidine (TMB) with H2O2, developing a blue color in aqueous solution. This catalytic activity was utilized to detect norovirus-like particles (NoV-LPs) in human serum. The enhanced colorimetric response was monitored using Ab-conjugated-Grp-Au NPs and found to depend on the NoV-LP concentration, exhibiting a linear response from 100pg/mL to 10μg/mL. The limit of detection (LOD) of this proposed method was 92.7pg/mL, 112 times lower than that of a conventional enzyme-linked immunosorbent assay (ELISA). The sensitivity of this test was also 41 times greater than that of a commercial diagnostic kit. The selectivity of the Grp-Au NPs was tested with other viruses, and no color changes were observed. Therefore, the proposed system will facilitate the utilization of the intrinsic peroxidase-like activity of Grp-Au NPs in medical diagnostics. We believe that the engineered catalytic Grp-Au NP hybrids could find potential applications in the future development of biocatalysts and bioassays.

Combining localized surface plasmon resonance with anodic stripping voltammetry for heavy metal ion detection

In this proof-of-concept study, we proposed a dual detection method for heavy metal ions based on nanostructured sensor device. This sensor device, named nano Lycurgus cup array, was characterized with hybrid structure of nano-scaled cups and gold nanoparticles. The hybrid periodic nanostructure could trigger localized surface plasmon resonance (LSPR) phenomenon, which was highly sensitive to refractive index changes. Then electrochemical measurement of anodic stripping voltammetry (ASV) was combined with LSPR for synchronous heavy metal ions detection, i.e., galvanizing metal ions onto the surface of the nanodevice whilst quantitatively recording electrochemical signals. Combining the electrochemical method with LSPR measurement, the dual detection system demonstrated a detection limit of part-per-billion level for aqueous heavy metal ions, such as lead, copper, and zinc. The LSPR measurement demonstrated a higher signal to noise rate (SNR) than electrochemical measurement and promising accuracy even with the presence of mixed solution, and was proved immune to the mechanical fluidic disturbance during the stripping phase which would deteriorate electrochemical signal in traditional electrochemical voltammogram. By presenting electrochemical signals on the dimension of LSPR, our method could be applied in highly integrated detection systems for on-spot detection.

Hemolysin coregulated protein 1 as a molecular gluing unit for the assembly of nanoparticle hybrid structures.

Hybrid nanoparticle (NP) structures containing organic building units such as polymers, peptides, DNA and proteins have great potential in biosensor and electronic applications. The nearly free modification of the polymer chain, the variation of the protein and DNA sequence and the implementation of functional moieties provide a great platform to create inorganic structures of different morphology, resulting in different optical and magnetic properties. Nevertheless, the design and modification of a protein structure with functional groups or sequences for the assembly of biohybrid materials is not trivial. This is mainly due to the sensitivity of its secondary, tertiary and quaternary structure to the changes in the interaction (e.g., hydrophobic, hydrophilic, electrostatic, chemical groups) between the protein subunits and the inorganic material. Here, we use hemolysin coregulated protein 1 (Hcp1) from Pseudomonas aeruginosa as a building and gluing unit for the formation of biohybrid structures by implementing cysteine anchoring points at defined positions on the protein rim (Hcp1_cys3). We successfully apply the Hcp1_cys3 gluing unit for the assembly of often linear, hybrid structures of plasmonic gold (Au NP), magnetite (Fe3O4 NP), and cobalt ferrite nanoparticles (CoFe2O4 NP). Furthermore, the assembly of Au NPs into linear structures using Hcp1_cys3 is investigated by UV–vis spectroscopy, TEM and cryo-TEM. One key parameter for the formation of Au NP assembly is the specific ionic strength in the mixture. The resulting network-like structure of Au NPs is characterized by Raman spectroscopy, showing surface-enhanced Raman scattering (SERS) by a factor of 8·104 and a stable secondary structure of the Hcp1_cys3 unit. In order to prove the catalytic performance of the gold hybrid structures, they are used as a catalyst in the reduction reaction of 4-nitrophenol showing similar catalytic activity as the pure Au NPs. To further extend the functionality of the Hcp1_cys3 gluing unit, Fe3O4 and CoFe2O4 NPs are aligned in a magnetic field and connected by utilization of cysteine-modified Hcp1. After lyophilization, a fiber-like material of micrometer scale length can be observed. The Fe3O4 Hcp1_cys3 fibers show superparamagnetic behavior with a decreasing blocking temperature and an increasing remanent magnetization leading to a higher squareness value of the hysteresis curve. Thus the Hcp1_cys3 unit is shown to be very versatile in the formation of new biohybrid materials with enhanced magnetic, catalytic and optical properties.

Resistive Switching Characteristics of Tantalum Oxide Thin Film and Titanium Oxide Nanoparticles Hybrid Structure.

The fabrication of hybrid structure with TiO2 nanoparticle assembly and Ta2O5 thin film layer was demonstrated. The close-packed nanoparticles could influence the resistive switching behaviors due to the huge numbers of interface states and vacancies in the nanoparticle assembly. The device with hybrid structure presented the typical bipolar resistive switching characteristics in the structure of Ti/TiO2/Ta2O5/Au on SiO2/Si substrate. The set voltage was observed at -0.7 V, and the reset voltage occurred at (-)-0.7 V, which was smaller than that of Ta2O5 layer only. The electrical conduction mechanisms were the ohmic conduction at low resistance state (LRS) and the space charge limited conduction at high resistance state (HRS), respectively. The devices showed stable current ratio of LRS to HRS. The temperature dependent properties of the devices were also investigated. The device with nanoparticle assembly showed better electrical characteristics with low HRS current level and stable LRS current level with respect to the temperature.

A novel surface-enhanced Raman spectroscopy substrate based on hybrid structure of monolayer graphene and Cu nanoparticles for adenosine detection

We present a novel surface-enhanced Raman spectroscopy (SERS) substrate based on a double-deck hybrid system assembled by monolayer graphene and Cu nanoparticle layer. The monolayer graphene film was grown by chemical vapor deposition (CVD) technology. The Cu nanoparticles with a uniform distribution were synthesized by liquor-phase reduction synthesis (LPRS) method on the SiO2 (3cm×3cm) substrate. By transferring graphene onto the Cu nanoparticle layer, we fabricated graphene/Cu nanoparticle hybrids (G/CuNPs) SERS substrate. The hybrid SERS substrate showed excellent Raman enhancement effect for adenosine. A reasonable linear response between the SERS intensity and adenosine concentration was obtained in the concentrations of 10−2–10−6M. This work provided amazing potential for sensitive label-free detection of biomolecular.

Nanoparticle-on-nanofiber hybrid membrane separators for lithium-ion batteries via combining electrospraying and electrospinning techniques

Nanoparticle-on-nanofiber hybrid membranes were prepared by electrospraying of SiO2 dispersions and electrospinning of polyvinylidene fluoride (PVDF) solution simultaneously. The aim of this study was to design new high-performance separator membranes with superior electrochemical properties such as high C-rate performance and good thermal stability compared to polyolefin based membranes. Uniform, bead-free fibrous structure with high amount of SiO2 nanoparticles exposed on PVDF nanofiber surfaces was observed. It was found that wettability and ionic conductivity were improved by dispersing SiO2 nanoparticles onto PVDF nanofiber surfaces. Electrochemical properties were enhanced due to the increased surface area caused by the unique hybrid structure of SiO2 nanoparticles and PVDF nanofibers. Compared with commercial microporous polyolefin membranes, SiO2/PVDF hybrid membranes had larger liquid electrolyte uptake, higher electrochemical oxidation limit, and lower interfacial resistance with lithium. SiO2/PVDF hybrid membrane separators were assembled into lithium/lithium iron phosphate cells and demonstrated high cell capacities and good cycling performance at room temperature. In addition, cells using SiO2/PVDF hybrid membrane separators showed superior C-rate performance compared to those using commercial microporous PP membrane.

Third-order nonlinear optical response in quantum dot–metal nanoparticle hybrid structures

Third-order nonlinear optical response of a semiconductor quantum dot, modulated by the metal nanoparticle (MNP), has been studied by using the effective mass and the rotating wave approximation. Considering multiple effects in the local and nonlocal optical response of the MNP, the dependence of the dispersion and the absorption on the size of the hybrid system are investigated in detail. By controlling the geometrical parameters of the hybrid structure and the direction of the electric field polarization, a significant enhancement of the nonlinear response is shown. The enhancement factor is nearly two orders of the magnitude, which is consistent with the experiment. Compared to the results obtained with the local effect, the center frequency shows blueshift obviously in the case of the nonlocal effect. In particular, the presence of the MNP leads to a strong absorption band appearance, which promises applications in the field of light transmission and the optical switching.

A facile route to fabricate an anodic TiO2 nanotube–nanoparticle hybrid structure for high efficiency dye-sensitized solar cells

The relatively low internal surface area of anodized TiO(2) nanotube arrays (TNAs) limits dye adsorption and light capturing in TNA-based dye-sensitized solar cells (DSSCs). Here, water treatment of as-anodized TNAs at room temperature was used to tailor the geometry of TNA walls in a controllable way, leading to a hybrid tube wall structure with the outer shell in a tubular morphology and the inner surface consisting of small particles. To enable front-side illumination in DSSCs, the TNAs with porous inner walls were transferred to transparent conductive oxide substrates by a self-detaching and transfer technique. The roughened water-treated TNAs show significantly enhanced internal surface area, leading to improved dye-loading and light-harvesting capabilities. Optimized performance was achieved after water treatment for 2 days, with a power conversion efficiency of 6.06%, increased by ∼33% compared to conventional TNAs. Furthermore, the hybrid TNA nanostructure provides excellent electron transfer and recombination characteristics, thus promising for high efficiency DSSCs.