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Non-destructive evaluation indices that correlate with the moisture resistance of integrated circuit packages are developed. These indices are developed from detailed studies on the functional groups in a moulding compound, and their effectiveness is verified experimentally. With these indices, one can ensure the moisture resistance of an individual package without the need of the standard humidity tests which require long test durations on limited number of samples where extrapolation with statistical uncertainty will be present.

This study presents the defectless zinc oxide nano-hexagonrods (ZnO-NH) structure decorated by gold nanoparticles (AuNPs) and its enhancement due to the tunable plasmonic field for photoluminescence sensor. The ZnO-NHs were grown on ITO glass substrate via a low-cost hydrothermal method followed by annealing at different seeding temperatures, respectively. A correlation has been established between annealing temperature and the defect level concerning the diameter and density of ZnO-NH verified by Raman and FE-SEM images analysis. A further coating of the gold layer over ZnO-NH via thermal evaporator exhibits the plasmonic field enhancement in visible range which revives after short rapid annealing treatment. The enhancement is due to the large surface area of the sensing area on the haxagonrods shape and robust plasmonic coupling between metal and ZnO which efficiently detects fluorescence signal of Rhodamine 6G(R6G) molecules. A drastic change of tunable enhanced signal was resulted by AuNPs size and morphology and elucidated by suitable energy diagram observed from quenching to highly enhanced signal using photoluminescence spectrum and its related linearity plot. Carried out in three different thicknesses of AuNPs spotting on ZnO-NH, 3, 5 and 7 nm, it was observed that 3 nm AuNPs resulted in six times higher enhancement of output signal at seeding temperature of 500o than the 5 and 7 nm gold NPs spotted ZnO-NH at same experimental conditions. By the proposed structure, a significant photoluminescence and plasmonics enhancement, the ease of tunability, and higher uniformity were achieved by the localized surface plasmon resonance (LSPR) from the AuNPs-decorated ZnO-NH and annealing process. Overall, the AuNPs- ZnO-NH hybrid offers a low-cost and simple fabrication potentially applied in a high-sensitive smart surface plasmonic optical sensor applications and can be a representative of new generations of photodiodes, solar cells, and metamaterials.

Roughing the metallic surface via oxidation-reduction cycles (ORC) to integrate the surface plasmon resonance and surface-enhanced Raman scattering (SERS) is predominant in developing sensor systems because of the facile preparation and uniform distribution of nanostructures. Herein, we proposed a distinctive ORC process: the forward potential passed through the oxidation of Au and reached the oxygen evolution reaction, and once the potential briefly remained at the vertex, the various reverse rates were employed to control the reduction state. The created hybrid Au-AuO x possessed electromagnetic and chemical enhancements concurrently, wherein the rough surface provided the strong local electromagnetic fields and significant interaction between AuO x and molecule to improve the charge transfer. The synergistic effects significantly amplified the intensity of Raman signal with an enhancement factor of 5.5 × 106 under the optimal conditions. Furthermore, the prepared SERS substrate can simultaneously identify and quantify the mixed edible pigments, Brilliant Blue FCF and Indigo Carmine, individually. This result suggested that the development of SERS sensor based on the proposed SERS-activated methodology is feasible and reliable.

Functionalization of a plasmonic substrate circumvents inadequate analyte localization within the sensing volume, which often threatens the sensitivity of a SERS method. Often nanoplasmonic substrates are functionalized by direct attachment to the host molecule, which affects their SERS activity. Herein, we report 3D-amino-functionalized Ag@SiO2 nanocubes with ultra-thin silica shell for the detection of small molecules in a flexible platform. The amino groups are introduced by silanizing the ultra-thin silica layer using different aminoslanes which improves sensitivity without sacrificing the colloidal and chemical stability of the core Ag nanocubes. Ag-SHINs functionalized with shorter chain length aminosilanes shows better SERS activity. The amino-functionalization effects a 3-fold SERS signal enhancement enabling label-free aspartame detection down to 71 μg mL−1 which is 1.5 times lower LOD than the non-functionalized Ag-SHINs. Analysis of spiked soft drink, as well as a mixture of aspartame and glucose, shows a robust performance signaling the selectivity and sensitivity of the substrate. The improved SERS performance is attributed to the hydrogen bonding induced localization of the analyte within the sensing volume. Added to this, the miniaturized paper platform with its 3D fibrous structure enhances the hotspot density and sample collection efficiency. This substrate can also be extended to other small molecules with the carboxylic group and amino acids as well, replacing the complicated bio-labeled detection schemes.

Cadmium selenide is a II–VI semiconductor model system known for its nanoparticle preparation, growth mechanism, luminescence properties, and quantum confinement studies. For the past 2 decades, various thermodynamically stable “magic-size nanoclusters (MSCs)” of CdSe have been observed, isolated, and theoretically calculated. Nevertheless, none of the proposed structures were experimentally confirmed due to the small crystal domains beyond the diffraction limit. With a combination of nondestructive SAXS, WAXS, XRD, XPS, EXAFS, and MAS NMR techniques, we were able to verify the phase transformation, shape, size dimension, local bonding, and chemical environments of (CdSe)13 nanoclusters, which are indicative of a paired cluster model. These experimental results are consistent with the size, shape, bond lengths, dipole moment, and charge densities of the proposed “paired-tubular geometry” predicted by computational approaches. In this article, we revisit the formation pathway of the mysterious (CdSe)13 nan...

In this article, we introduce the theory and instrumentation that is relevant to nanospectroscopy imaging techniques, including near-field scanning optical microscope (NSOM) and tip-enhanced Raman scattering (TERS) imaging. We also demonstrate the NSOM and TERS imaging functions in emiconductor samples. Our findings support the view that NSOM and TERS imaging techniques can increase the space resolution and emphasize the surface information for the target surface layer. Thus, these techniques are applicable to the studies of materials with nanoscale patterns in the future.

This work studies the interdiffusion effect of Er ions in Er 2 O 3 and Si ions in SiO 2 on the photoluminescent (PL) properties of Er 2 O 3 /SiO 2 films. Er 2 O 3 layers are deposited on thermally oxidized Si substrates by reactive radio-frequency magnetron sputtering. Different interdiffusion behaviors are observed by thermally treating films with rapid thermal annealing (RTA) and tube furnace annealing (TFA) at 900–1200 °C. Surface morphological and compositional properties are measured by optical microscopy, atomic force microscopy, and secondary ion mass spectroscopy. Surface roughness of composite films increases with the annealing temperature due to growth in grain size. The Er/Si interdiffusion across the Er 2 O 3 /SiO 2 interface is observed when the annealing temperature exceeds 1000 °C for RTA and 900 °C for TFA. Thermal annealing effects in the oxygen ambient include the Er doping in the SiO 2 layer, the formation of erbium silica, and the reduction of defect density. These three factors facilitate the increase of active Er ions and the enhancement of PL intensity. The PL intensity increases with the Er/Si interdiffusion thickness for RTA- and TFA-treated films. Enhancement of PL intensity with the annealing temperature is attributed to the Er/Si interdiffusion and the reduction of defect density.

The rapid and reliable detection of a diverse set of biomolecules, such as metabolites, pharmaceuticals, nucleic acids, amino acids, proteins, and peptides, requires analytical techniques capable of label-free chemical identification. Inelastic light scattered by a molecule, a quantized vibrational signature, is the physical phenomenon behind Raman spectroscopy [1]. Despite the rich information offered by regular Raman spectroscopy, it has not been the primary choice as a handy analytical tool comparable to Fourier-transform infrared and ultraviolet-visible spectroscopy due to its inherently small scattering cross section. The signal is weak for most molecules except in some special cases of resonating molecular structures. For example, the benzene molecule, which is relatively strong for Raman scattering, exhibits a scattering cross section of 2.6 x 10-29 cm2?molecule-1?sr-1. This value is 12-14 orders of magnitude lower than a typical fluorescence cross section [2].

Impact of electromagnetic waves and fields on neighboring devices may lead to product malfunctioning and system failures, which, in turn, may result in unexpected incidents and/or even major public safety issues. This study combines measures of shielding, filtering, and grounding to design parameters at the beginning of product design by taking industrial panel PC as an example. It employs the Taguchi method to plan and conduct experiments. The control factors are PCB and mechanic design related parameters while the noise factors considered are peripherals connected to the device for its operation. The optimal parameters combination is identified as: number of grounding screw holes at 14 and with cooling aperture of casing at diameter of 3 mm and of staggered layout. The aforementioned optimal design can reduce electromagnetic interference noises down to the tune of 23 dB (at frequency of 406.36 MHz) which is way below the 47 dB limits given by international specification.

Surface-enhanced Raman scattering (SERS) and fluorescence microscopy are a widely used biological and chemical characterization techniques. However, the peak overlapping in multiplexed experiments and rapid photobleaching of fluorescent organic dyes is still the limitations. When compared to Ag nanocubes (NCs), higher SERS sensitivities can be obtained with thin shelled silica Ag@SiO2 NCs, in contrast metal-enhanced photoluminescence (MEPL) is only found with NCs that have thicker silica shells. A 'dual functionality' represented by the simultaneous strengthening of SERS and MEPL signals can be achieved by mixing Ag@SiO2 NCs, with a silica shell thickness of ~1.5nm and ~4.4nm. This approach allows both the Ag@SiO2 NCs SERS and MEPL sensitivities to be maintained at ~90% after 12weeks of storage. Based on the distinguished detection of creatinine and flavin adenine dinucleotide in the mixture, the integration of SERS and MEPL together on a stable single plasmonic nanoparticle platform offers an opportunity to enhance both biomarker detection sensitivity and specificity.

A one-step process combining chemical modification and exfoliation for obtaining a graphene (Gs) derivative from pristine graphite is conducted through Friedel–Crafts chemical acylation. This electrophilic substitution reaction results in the carboxylic group (–COOH) of niacin transforming into an acylium ion (–C+ O), which is an active species that replaces the sp2 C H of graphite. In addition, highly viscous polyphosphoric acid under mechanical stirring was used to exert strong shear stress on and consequently exfoliate the graphite layers. Raman spectra and absorption spectra demonstrate that the obtained graphene-1-one-pyridine (GsNc) has a highly conjugated structure that facilitates electron transfer in electrochemical processes. This novel GsNc possess high sensitivity toward H2O2 (1157.1 μA mM−1 cm−2) within a linear concentration range of 1 μM to 5 mM. The proposed enzyme-free H2O2 sensor exhibits high selectivity and excellent stability. Furthermore, a choline biosensor is developed for detecting H2O2 released in bioreactions. In this biosensor, positively charged GsNc provides optimal conditions for immobilizing choline oxidase (ChOx) through electrostatic interactions. This immobilization retains 83.4% of ChOx bioactivity and is thus excellent for choline determination. This modified electrode has high potential for application in oxidase-based biosensors.

Purpose Differing from previous studies trying to solve the electromagnetic compatibility (EMC) issue by addressing single factor, this study aims to combine measures of shielding, filtering and grounding to design parameters with the Taguchi method at the beginning of product design to come up with the optimal parameter combination. Design/methodology/approach EMC-related performance such as radiated emission, conduction interference and electrical fast transient/burst immunity (EFT) are response variables, whereas the printed circuit board and mechanic design-relevant parameters are considered as control factors. The noise factors are peripherals used together with the tablet. Findings The optimal design parameter matrix based on results from the application and integration of multivariate analysis method of principal component grey relation and technique for order preference by similarity to ideal solution suggests 14 grounding screw holes, cooling aperture of casing at diameter of 3 mm and staggered layout and 300O filter located at source of noise. Validation of this matrix shows around 10, 1 and 8 per cent improvement in radiation, conduction interference and EFT immunity. Originality/value The multivariate quality parameters’ design method proposed by this study improves EMC characteristics of products and meets the design specification required by customer, accelerating electronic product research and development process and complying with electromagnetic interference test regulations set forth by individual country.

Organolead halide perovskites are an impressive and relatively recent class of light-absorbing materials for solar cells and light-emitting devices. It has been reported that exposure of perovskite materials to light has negative impacts on device performance. Also, surface recombination has been reported as a major obstacle to the total carrier lifetime in perovskite polycrystalline thin films. Herein, we explored the role played by nanosecond pulsed UV laser-irradiation in carrier dynamics in perovskite thin films. Steady-state and time-resolved photoluminescence measurements revealed the interplay of disorder and heterogeneity on photoexcited carrier dynamics, while in situ micro Raman spectroscopy and angle dispersive X-ray diffraction showed the mechanisms of crystal phase reconstruction. Exposure to laser light leads to rapid crystal phase reconstruction and hence, unexpectedly, extends the PL lifetime by fourfold instead of promoting degradation. This verifies that nanosecond pulsed laser irradiation plays a beneficial role in improving optoelectronic material parameters. Our findings reveal that pulsed laser irradiation is a new approach to the reconstruction of the microstructure and offers beneficial effects in the manufacture of perovskite solar cells. Moreover, this work provides a clear insight towards identifying the physical origin behind the disorder, heterogeneity, film reconstruction and nano-structuring as well as their correlation with improved PL lifetimes.

A robust flexible paper-plasmonic hybrid SERS substrate is reported by exploiting the intrinsic properties of filter paper and anisotropic Ag@SiO2 nanocubes. The fibrous structure of paper promotes the assemblage of sharp-edged nanostructures which significantly improved the SERS activity. An inexpensive sensing platform with reasonable distribution and interparticle spacing of nanocubes was obtained by filtering Ag@SiO2 through a miniaturized filter paper. The thin silica shell improved the stability and interparticle spacing of silver nanocubes in the sensing platform, rendering enhanced SERS activity through the plasmon-coupling effect as compared to a conventional rigid substrate. Assessment of the analytical performance of the substrate for melamine quantification showed a good linearity (R2 = 0.9948) up to 1 mg L−1 with a limit of detection of 0.06 mg L−1. The detection limit in liquid milk was down to 0.17 mg L−1, which is below the permissible residue limit signifying adequate sensitivity for real sample analysis with less sample treatment.

The interaction of plasmonic nanoparticles with a dielectric platform gives rise to unique optical behaviors and this can be maneuvered to improve the plasmonic/SERS performances of a substrate. Herein, dielectric modified plasmonic-paper SERS substrate is developed by assembling Ag@SiO2 nanocubes on Fe-TiO2 nanosheets (NS) modified paper. The Fe-TiO2 NS being visible light responsive significantly alters the optical property of the paper and serves as a dielectric underlay for the Ag nanocubes. Hence, the incident light reflected back from the dielectric nanosheets couples with the scattered light from the Ag nanocubes leading to spatially enhanced electromagnetic field improving the SERS enhancement. The prepared dielectric modified plasmonic-paper has an average enhancement factor (EF) of 1.49 × 107 using R6G as a probe molecule. This value is superior to unmodified plasmonic-paper highlighting the coupling effect of the dielectric nanosheets. The substrate shows robust detection performance for thiabendazole and achieves a limit of detection (LOD) of 19 μg/L, which is 4-fold more sensitive than unmodified plasmonic paper. Direct swabbing test of thiabendazole sprayed apple fruit shows a discernible Raman signal down to 15 ppb indicating the utility of the substrate for point-of-need applications in food safety.

Generating a sustainable energy source through photoelectrochemical (PEC) water splitting requires a suitable photocatalyst. A [101]-oriented rutile TiO2 nanorod (NR) array in heterojunction with anatase on a fluorine-doped tin oxide (FTO) substrate is successfully prepared using a facile single-step hydrothermal process. The presence of anatase phase over the predominant rutile NRs’ surface is confirmed by transmission electron microscopy and tip-enhanced Raman spectroscopy. Solar water-splitting performances of anatase–rutile heterojunction with low energy (101) and high energy (001) rutile facets are compared. The low energy (101) facet rutile–anatase heterojunction shows higher photoconversion efficiency of 1.39% at 0.49 VRHE than the high energy (001) facet rutile–anatase heterojunction (0.37% at 0.73 VRHE). The mechanism for enhanced photocatalytic activity of the low energy (101) facet rutile–anatase heterojunction has been proposed. The role of NaCl in tuning the anatase portion, morphology, and P...

A simple, low-temperature hydrothermal method and atomic layer deposition (ALD) were used to fabricate ZnO nanostructures as subwavelength-structure antireflection layers (SWS ARLs) on Si solar cells. ZnO seed layers with wafer-scale uniformity were prepared, and ALD was used to reproduce two types of ZnO-based structures, nanorod arrays (NRAs) and nanotip arrays (NTAs). The study examined diammonium phosphate concentrations during growth, conducted simulations based on three-dimensional finite-difference time-domain and reflection analyses, performed X-ray diffractometer, field-emission scanning electron microscope, and high-resolution transmission electron microscope characterizations, measured total reflectance spectra by using a spectrophotometer with integrated spheres, and ran solar simulations to determine the efficiency of the Si solar cells. Coating the ZnO NTAs on the Si solar cells yielded a low total reflectance over a broad band range and produced omnidirectional light scattering on the cells, causing incident light to have a shallow penetration depth near the p–n junction and leading to an increase in short current density ( Jsc ). Coating the ZnO NTAs with an Al 2 O 3 shell induced continuous variation in the refractive index, further decreasing the total reflectance to approximately 5.5%, and protected the ZnO NTAs from the harmful acidic environment. Significantly increasing the J sc and η levels of the Si solar cells, the Al 2 O 3 @ZnO-NTA antireflection structure produced a high efficiency of 17.79%. Its superior performance, including low and wideband reflectance, a low process temperature, and a significant increase in efficiency, indicates the potential of this antireflective structure for enhancing solar cell efficiency in photovoltaic devices.

Potassium hydroxide solution was used to etch un-doped GaN grown on the sapphire substrate at 180 and 260 °C. We illustrated the etching phenomenon in detail and probed its mechanism in the wet etching process. By multiplying the planar density and the number of dangling bonds on the N atom, we proposed the etching barrier index (EBI) to describe the difficulty degree of each lattice facet. The raking of EBI will be +c-plane > a-plane > m-plane > −c-plane > (10-1-1) plane > r-plane. Combining the EBI with SEM results, we thoroughly studied the whole etching process. We confirmed that in our research, KOH wet etching on GaN starts from the r-plane instead of the +c-plane or −c-plane, which differs from other studies. We also found that during the high-temperature etching process, there are two etching approaches. In one, the etching begins vertically from the top to the bottom, then horizontally, and finally reversely from the bottom to the top. In the other, etching pits will develop into a hexagonal hole of the sidewall of m-plane.

In this study, the water-gas shift (WGS) reaction is investigated over Cu/SiO2 catalysts with and without an iron promoter. By adding a small amount of iron, the catalytic activity and stability of Cu/SiO2 are effectively improved. The oxidation of Cu/SiO2 catalysts is considered to be the major factor for the deactivation of Cu catalysts. Fe oxides in Cu–Fe/SiO2 catalysts surprisingly inhibit the oxidation of Cu and increase the catalytic stability of Cu–Fe/SiO2 catalysts. The role of the Fe promoter in Cu/SiO2 catalysts in the WGS is thoroughly investigated using a variety of experiments, such as H2-temperature-programmed reduction (H2-TPR), IR spectroscopy, temperature-programmed desorption (TPD) and in situ X-ray absorption spectroscopy (XAS). For the Cu–Fe/SiO2 catalysts, both reactants, CO and H2O, prefer to adsorb on the defect sites on the Cu surface and on Fe oxides, respectively. The higher performance and stability of the Cu–Fe/SiO2 catalyst for the WGS reaction is explained based on the rapid dissociation of H2O on the Fe promoter.

This paper reports the combined plasmon coupled - surface energy transfer (PC-SET) and a distance-dependent model constructed by gold nanoparticles (GNPs) over zinc oxide nanorod (ZnO-NR) as a robust and tunable plasmontronic fluorescence regime for the detection of rhodamine 6G (R6G). Further, the deposition of metal created extraordinary contact through ZnO-NR utilizing a rapid thermal process (RTP) allowing the interaction of plasmon-coupled nature and surface energy transfer from the donor (R6G) to the acceptor (ZnO). The percentage of energy transfer efficiency continuously decreased with the increment of GNPs size, shown by 72.93, 67.52 and 47.86%, corresponding to the increase of the distance between the donor and acceptor of 63.03, 67.25, and 82.49 A, respectively. In other words, the efficiency of PC-SET complied the 1/d4 distance dependence model between donor and acceptor molecules with the detection of long-distance ranges from 46.95 to 120 A. These findings suggest that PC-SET process has a more realistic agreement with experimental outcomes and highly supports quenching efficiency impacts related to the size of GNPs, in which the smaller size of NPs causes’ greater effectiveness towards challenges in light harvest enhanced sensing system.

In this study, we prepared photoluminescent l-cysteine (Cys)-capped gold nanoclusters (Cys-Au NCs) via NaBH4-mediated reduction of aggregated coordination polymers (supramolecules) of -[Cys-Au(i)]n-. The -[Cys-Au(i)]n- supramolecules with interesting chiral properties were formed through simple reactions of chloroauric acid (HAuCl4) with Cys at certain pH values (pH 3-7). The -[Cys-Au(i)]n- polymers could self-assemble into -[Cys-Au(i)]n- supramolecules with irregular morphologies and diameters larger than 500 nm through stacked hydrogen bonding and zwitterionic interactions between Cys ligands and through Au(i)Au(i) aurophilic interactions in solutions with pH values ≤7. The photoluminescent Au NCs (quantum yield = 11.6%) dominated by a Au13 core were embedded in -[Cys-Au(i)]n- supramolecules after NaBH4-mediated reduction. The optical and structural properties of Cys-Au NCs/-[Cys-Au(i)]n- nanocomposites were investigated, revealing that the interaction between Cys ligands plays a critical role in the self-assembly of -[Cys-Au(i)]n- supramolecules and in the formation of photoluminescent Cys-Au NCs embedded in the supramolecules. To further demonstrate that the photoluminescence properties and structures of the nanocomposites are mediated by the intermolecular forces of thiol ligands, other thiol ligands (l-penicillamine, l-homocysteine, 3-mercaptopropionic acid, and l-glutathione) and a ligand-crosslinking agent [bis(sulfosuccinimidyl) suberate; BS3] were used. We concluded that the electrostatic interactions, hydrogen bonding and steric effects dominate the polymer self-assembly into thiol-ligand-Au(i) supramolecules and thus the formation of Au NCs. Our study provides insights into the bottom-up synthesis of photoluminescent Au NCs from thiol-ligand-Au(i) complexes, polymers, and supramolecules. The hybrid Au NCs/-[Cys-Au(i)]n- nanocomposites can potentially be employed as drug carriers and bioimaging agents.

Matrix metalloproteinases (MMPs), specifically MMP-2, MMP-7, and MMP-9, have been discovered to be linked to many forms of vascular diseases such as stroke, and their detection is crucial to facilitate clinical diagnosis. In this work, we prepared a class of optical interference-free SERS nanotags (CO-nanotags) that can be used for the purpose of multiplex sensing of different MMPs. Multiplex detection with the absence of cross-talk was achieved by using CO-nanotags with individual tunable intrinsic Raman shifts of CO in the 1800–2200 cm–1 region determined by the metal core and ligands of the metal carbonyl complex. Boolean logic was used as well to simultaneously probe for two proteolytic inputs. Such nanotags offer the advantages of convenient detection of target nanotags and high sensitivity as validated in the ischemia rat model.

Graphene nanodiscs (GNDs), functionalized using NH3 plasma, as charge trapping sites (CTSs) for non-volatile memory applications have been investigated in this study. The fabrication process relies on the patterning of Au nanoparticles (Au-NPs), whose thicknesses are tuned to adjust the GND density and size upon etching. A GND density as high as 8 × 1011 cm−2 and a diameter of approximately 20 nm are achieved. The functionalization of GNDs by NH3 plasma creates N H+ functional groups that act as CTSs, as observed by Raman and Fourier transform infrared spectroscopy. This inherently enhances the density of CTSs in the GNDs, as a result, the memory window becomes more than 2.4 V and remains stable after 104 operating cycles. The charge loss is less than 10% for a 10-year data retention testing, making this low-temperature process suitable for low-cost non-volatile memory applications on flexible substrates.

The binding of organometallic osmium carbonyl clusters onto the surface of gold nanoparticles (10OsCO-Au NPs) greatly enhanced the CO stretching vibration signal at ~2100 cm−1, which is relatively free from interference due to the absorbance of biomolecules. By utilizing the acetylcholinesterase (AChE) mediated hydrolysis of acetylthiocholine to thiocholine where the activity of AChE is inhibited by the presence of organophosphate pesticides (OPPs), the subsequent thiocholine-induced aggregation of 10OsCO-Au NPs can be monitored by the change in color of the NPs solution and the variation in intensity of the SERS CO signal. The change in color offers a fast pre-screening method, whereas monitoring via SERS is used for greater accuracy and lower limit of detection (0.1 ppb) for quantitative detection. Its potential as a quick and accurate method of OPPs monitoring in consumer products was demonstrated in the detection of OPPs in real spiked samples such as beer.

Hydrogenated titanium dioxide has attracted intensive research interests in pollutant removal applications due to its high photocatalytic activity. Herein, we demonstrate hydrogenated TiO2 nanofibers (H:TiO2 NFs) with a core-shell structure prepared by the hydrothermal synthesis and subsequent heat treatment in hydrogen flow. H:TiO2 NFs has excellent solar light absorption and photogenerated charge formation behavior as confirmed by optical absorbance, photo-Kelvin force probe microscopy and photoinduced charge carrier dynamics analyses. Photodegradation of various organic dyes such as methyl orange, rhodamine 6G and brilliant green is shown to take place with significantly higher rates on our novel catalyst than on pristine TiO2 nanofibers and commercial nanoparticle based photocatalytic materials, which is attributed to surface defects (oxygen vacancy and Ti3+ interstitial defect) on the hydrogen treated surface. We propose three properties/mechanisms responsible for the enhanced photocatalytic activity, which are: (1) improved absorbance allowing for increased exciton generation, (2) highly crystalline anatase TiO2 that promotes fast charge transport rate, and (3) decreased charge recombination caused by the nanoscopic Schottky junctions at the interface of pristine core and hydrogenated shell thus promoting long-life surface charges. The developed H:TiO2 NFs can be helpful for future high performance photocatalysts in environmental applications.