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Polymer nanocomposites, prepared by incorporating functional nanoparticles (NPs) into a polymer matrix, have advantages of utilizing functionalities of polymers and NPs. Among them, transparent high‐refractive‐index polymer nanocomposites (THPNs), prepared by incorporating highly refractive NPs into polymer matrices, are advantageous for effectively manipulating light. This review focuses on the introduction of fabrication of THPN prepared by incorporating inorganic‐oxide NPs, especially zirconia (ZrO2), and its characteristics as an optical material. ZrO2 NPs have a high refractive index and high transmittance in visible light regions with high and narrow optical bandgap energy. Since ZrO2 NPs are harmless to humans and physically and chemically stable, they are suitable for applications of advanced optical materials for display and energy devices. Various fabrication methods of THPN with ZrO2 NPs and surface modifications of ZrO2 NPs to prevent agglomeration are introduced. Principles and specific applications, which THPN could work with and for, are introduced as well. [ABSTRACT FROM AUTHOR]

We experimentally demonstrate thatplasmonic nanoparticles embeddedin the evanescent field of subwavelength optical waveguides (WGs)are highly sensitive to distances normal to the propagation of light,showing an ∼10× increase in spatial resolution comparedto the optical field decay of the WG. The scattering cross-sectionof the Au nanoparticle is increased by the plasmon–dielectriccoupling interaction when the nanoparticle is placed near the dielectricsurface of the WG, and the decay of the scattering signal is enhanced,showing angstrom level distance sensitivity within 10 nm from theWG. Numerical studies with the finite-difference time-domain (FDTD)method correlate well with the experimental results. To demonstratereal-time monitoring of a single molecule stretching in the evanescentfield, we linked individual single-stranded DNA molecules betweenthe WG and plasmonic nanoparticles and pushed on the nanoparticleswith fluidic forces. The simple design and ease of obtaining opticalfeedback on molecular displacements makes our approach ideal for newin situ force sensing devices, imaging technologies, and high-throughputmolecular analysis. [ABSTRACT FROM AUTHOR]

We report a systematic study of light coupling at junctions of overlapping SnO2 nanofiber waveguides (WGs) as a function of gap separation and guided wavelength. The junctions were assembled on silica substrates using micromanipulation techniques and the gap separation was controlled by depositing thin self-assembled polyelectrolyte coatings at the fiber junctions. We demonstrate that the coupling efficiency is strongly dependent on the gap separation, showing strong fluctuations (0.1 dB/nm) in the power transfer when the separation between nanofibers changes by as little as 2 nm. Experimental results correlate well with numerical simulations using three-dimensional finite-difference time-domain techniques. To demonstrate the feasibility of using coupled nanofiber WGs to modulate light, we encased the junctions in an environment-responsive matrix and exposed the junctions to gaseous vapor. The nanofiber junctions show an ∼95% (or ∼80%) modulation of the guided 450 nm (or 510 nm) light upon interaction with the gaseous molecules. The results reveal a unique nanofiber-based sensing scheme that does not require a change in the refractive index to detect stimuli, suggesting these structures could play important roles in localized sensing devices including force-based measurements or novel chemically induced light modulators. [ABSTRACT FROM AUTHOR]

Incorporating noble‐metal plasmonic nanoparticles (NPs) enhances the optoelectronic properties of perovskite solar cells (PSCs) but at a higher cost. In this work, the overlooked potential of refractory plasmonic materials is highlighted as a cost‐effective alternative additive in PSC research. This investigation aims to stimulate interest in this area by showcasing the theoretical and practical impacts of TiN plasmonic NPs when integrated into PSCs. TiN plasmonic NPs present a cost‐effective yet underexplored option. This study explores the impact of TiN NPs on PSCs through theoretical and experimental approaches. Finite‐difference time‐domain (FDTD) optical simulations and empirical data indicate that TiN NPs increase absorption and reduce reflectance in PSCs, driven by surface plasmon resonance and the significant growth of perovskite grains from 450 to 1400 nm. These NPs also regulate the perovskite crystallization rate by adsorbing DMF/DMSO, fostering larger grain formation. Improved band alignment and decreased trap states enhance charge transport and diminish non‐radiative recombination losses. As a result, PSC efficiency with optimal TiN NP concentration increased from 19.07% to 21.37%. Additionally, TiN‐enhanced PSCs display better stability, retaining 98.1% of their original PCE after 31 days under ambient conditions. [ABSTRACT FROM AUTHOR]

Solar-to-steam (STS) generation based on plasmonic materials has attracted significant attention as a green method for producing fresh water. Herein, a simple in situ method is introduced to fabricate Au nanoparticles (AuNPs) on cellulose filter papers as dual-functional substrates for STS generation and surface-enhanced Raman spectroscopy (SERS) sensing. The substrates exhibit 90% of broadband solar absorption between 350 and 1800 nm and achieve an evaporation rate of 0.96 kg·m−2·h−1 under 1-sun illumination, room temperature of 20 °C, and relative humidity of 40%. The STS generation of the substrate is stable during 30 h continuous operation. Enriched SERS hotspots between AuNPs endow the substrates with the ability to detect chemical contamination in water with ppb limits of detection for rhodamine 6G dye and melamine. To demonstrate dual-functional properties, the contaminated water was analyzed with SERS and purified by STS. The purified water was then analyzed with SERS to confirm its purity. The developed substrate can be an improved and suitable candidate for fresh water production and qualification. [ABSTRACT FROM AUTHOR]

Interfacial solar steam generation (ISSG) is one of the promising solutions in the field of water filtration, desalination, and solvent recovery. For the industrial applications of the technology, there is a need for developing highly durable, thermally stable, and inert light absorbers. Therefore, this work addresses this issue by synthesizing black Titania (B–TiO 2) via vacuum annealing and depositing it on glass fiber (GF) via vacuum filtration with an ethyl cellulose binder. According to the characterization techniques analyses, the change of colour is attributed to the occurrence of oxygen vacancies in the surface layers of TiO 2 nanoparticles during vacuum annealing. The deposition parameters were optimized for achieving a maximum solar-weighted light absorptance of 95.7%. The optimized B–TiO 2 GF was applied for the steam generation experiments and achieved the evaporation rate of 1.53 kg m−2 h−1, which corresponds to solar-steam conversion efficiency of 97.7 % under standard measurements condition of AM 1.5 G sun and ambient temperature and relative humidity of 20 °C and 40% respectively. Thanks to the high durability and chemical inertness of B–TiO 2 GF it was applied for water filtration in extreme conditions of acidic/alkaline water and high-sun illumination (up to 35-sun). Worth noting that for high-sun experimentation there is a need to use a binder to improve particle attachment to the glass fibers. • Eco-friendly synthesis of black titania is achieved. • Highly durable inorganic light absorber is realized for solar desalination. • Oxygen vacancies are enriched in black titania. • Ethyl cellulose acts as a binder for the light absorber. • Interfacial solar steam generation is applied using black titania. [ABSTRACT FROM AUTHOR]

Here, highly transparent nanocomposite films with an adjustable refractive index were fabricated through stable dispersion of ZrO2 (n = 2.16) nanoparticles (NPs) subjected to surface modification with SiO2 (n = 1.46) in polydimethylsiloxane (PDMS) (n = 1.42) using the Stöber method. ZrO2 NPs (13.7 nm) were synthesized using conventional hydrothermal synthesis, and their surface modification with SiO2 (ZrO2@SiO2 NPs) was controlled by varying the reaction time (3–54 h). The surface modification of the NPs was characterized using Fourier-transform infrared spectroscopy, dynamic light scattering, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and ellipsometry. The surface modification was monitored, and the effective layer thickness of SiO2 varied from 0.1 nm to 4.2 nm. The effective refractive index of the ZrO2@SiO2 NPs at λ = 633 nm was gradually reduced from 2.16 to 1.63. The 100 nm nanocomposite film was prepared by spin-coating the dispersion of ZrO2@SiO2 NPs in PDMS on the coverslip. The nanocomposite film prepared using ZrO2@SiO2 NPs with a reaction time of 18 h (ZrO2@SiO2-18h-PDMS) exhibited excellent optical transparency (Taverage = 91.1%), close to the transparency of the coverslip (Taverage = 91.4%) in the visible range, and an adjustable refractive index (n = 1.42–1.60) as the NP content in the film increased from 0 to 50.0 wt%. [ABSTRACT FROM AUTHOR]

Optical antennas interface an object with optical radiationandboost the absorption and emission of light by the objects throughthe antenna modes. It has been much desired to enhance both excitationand emission processes of the quantum emitters as well as to interfacemultiwavelength channels for many nano-optical applications. Herewe report the experimental implementation of an optical antenna operatingin the full visible range via surface plasmon currents induced ina defect-free single-crystalline Ag nanowire (NW). With its atomicallyflat surface, the long Ag NW reliably establishes multiple plasmonicresonances and produces a unique rainbow antenna radiation in theFresnel region. Detailed antenna radiation properties, such as radiatingnear-field patterns and polarization states, were experimentally examinedand precisely analyzed by numerical simulations and antenna theory.The multiresonant Ag NW nanoantenna will find superb applicationsin nano-optical spectroscopy, high-resolution nanoimaging, photovoltaics,and nonlinear signal conversion. [ABSTRACT FROM AUTHOR]

Nanosized plasmonic metallic nanoparticles such as Pd have gained significant attention due to their diverse applications in catalysis, sensing, and light-to-heat conversion. However, the development of scalable and environmentally friendly synthesis routes for such nanoparticles is crucial for the sustainable development of industrial applications. In this work, we address this challenge by synthesizing Pd-nanoparticles on the cellulose filter paper (Pd-Cellulose) via two scalable green synthesis routes: low-temperature thermal and plasma synthesis. We found that adjusting synthesis conditions allowed us to achieve an optimum morphology that maximizes light absorptance. The nature of the reduction species during synthesis significantly impacts the morphology and heat-transfer properties of the resulting material. Compared to thermally synthesized Pd-Cellulose, the absorbers synthesized with plasma have smaller particles size and higher coverage, which leads to higher broadband light absorptance and more intense heat transfer to the surroundings. The optimized Pd-based light absorbers were utilized in a solar-to-steam desalination system, resulting in an evaporation rate of 1.30 kg/m2h for the open system and a filtration rate of 0.7 kg/m2h for the closed system. Our findings provide insights into the green and scalable synthesis and optimization of Pd-based light absorbers and their potential application in sustainable renewable energy systems. [Display omitted] • Pd-nanoparticles are synthesized via two synthesis routes: thermal and plasma synthesis. • The optimum morphology is achieved for maximized light absorptance. • The nature of the reduction species impacts the morphology and heat-transfer properties of nanoparticles. • A new lab-scale solar-to-steam desalination system with Pd-Cellulose is developed. [ABSTRACT FROM AUTHOR]

In contrast with the conventional in situ and ex situ methods for the preparation of polymer-based nanocomposites in which the polymer matrix (for both methods) and metal nanoparticles (for the ex situ method only) are prepared separately prior to being combined to form the composite, polyhedral gold nanocrystal/polymer composite film was successfully synthesized through combining the in situ formation of gold nanocrystals (AuNCs) and simultaneous polymerization of the polyelectrolytes from ionic liquids and surfactants under atmospheric pressure plasma. The composite film contained a large number of well-shaped polyhedral AuNCs. The AuNCs are stereoscopically distributed in the polyelectrolyte matrix without agglomeration. The size of the AuNCs prepared in a 3 mm deep reactor decreased along the cross section of the composite film from top to bottom, while they were uniform in size when they were prepared in a 5 mm deep reactor. In the presence of the Au precursors, the polymer film thickness increases to 7.03 μm, which is two-fold thicker than that of the polymer film prepared without adding Au precursors. Through the density functional theory (DFT) calculations, the critical role of Triton X100 was clearly demonstrated in the formation of the well-shaped AuNCs. The composite film exhibited the reduction of ∼66% in Young's modulus and the reduction of ∼44% in hardness compared to the neat polymer film. Finally, an appropriate mechanism is proposed for the formation of the polyhedral AuNC/polyelectrolyte composite film. [ABSTRACT FROM AUTHOR]

An arsenobetaine ( AsB) standard solution with metrological traceability to the International System of Units was developed as a calibration standard for the quantitative analysis of AsB. An arsenic-specific mass balance method was established for the certification of the AsB standard solution. The accurate mass fraction of total arsenic in the solution was determined by instrumental neutron activation analysis with direct comparator method. Arsenic-containing impurities were evaluated by arsenic speciation analysis using liquid chromatography-inductively coupled plasma mass spectrometry ( LC-ICP-MS). Two LC separation methods were adopted for comprehensive coverage of the impurities, which include the reversed-phase LC with ion-pairing and the cation exchange chromatography. The only arsenic-containing impurity observed by LC-ICP-MS was trace level of trimethylarsine oxide. The mass fraction of arsenic in the form of AsB was obtained by subtracting the arsenic mass fractions of the impurities from the total arsenic in the standard solution. The between-bottle inhomogeneity of AsB content in the standard solution was less than 0.7%, which was estimated from the relative standard deviation of the measurement results obtained from 10 representative sample bottles from a batch. The certified value of AsB and its expanded uncertainty as arsenic mass fraction were assigned to be (51.28 ± 1.17) mg/kg ( k = 2 approximately at 95% level of confidence). [ABSTRACT FROM AUTHOR]

The mechanical and chemical stability of the light-absorber creates a limitation of the STS applications, especially in harsh operating conditions such as high temperature or aggressive solvents environment. The current study addresses the issue by proposing a highly stable and durable light absorber based on the gold nanoparticles (Au NPs) immobilized on the mesoporous silica-covered glass fiber (MSGF). Mesoporous silica coating improves the attachment of Au NPs to the fiber surface, while simultaneously increasing specific surface area. The synthesis parameters of the mesoporous silica layer and the Au NPs were adjusted to obtain favorable morphology, resulting in a 16.7% increase in the total solar weighted absorptance. The STS system based on two-dimensional Au-MSGF achieved the highest evaporation rate of 1.22 kg·m−2·h-1 under 1 sun illumination at 20 °C and relative humidity of 40%. Furthermore, the thermal stability and durability of glass fiber allowed the application of Au-MSGF for the STS at sunlight illumination intensities as high as 50-suns without any visible or performance degradation over extended periods. The inertness of the Au-MSGF plays an important role in the solvent recovery applications of the STS system. It was found that the hydrophobic coating of the light absorber improves the performance of the STS system for non-polar solvent recovery. The results indicate a significant (over 100% as compared to the evaporation in the darkroom) evaporation rate increase of octane and decane in the STS system operating under 1 and 2 suns, making them suitable for the STS solvent recovery. • A highly stable all-inorganic absorber is developed for STS generation. • SiO 2 coating increases the surface area of glass fiber. • High sun STS generation is possible up to 50 Sun. • Solar induced solvent recovery using STS is successfully demonstrated. • STS-solvent recovery is efficient for solvents with low p v. [ABSTRACT FROM AUTHOR]

Freshwater shortage and the growing demand for electricity are the most common issues on the path toward achieving global sustainability. Therefore, finding creative solutions involving the use of renewable energy sources presents the main challenge. Herein, we developed a cost-effective and highly efficient 2-in-1 integrated conical device consisting of multi-walled carbon nanotubes deposited filter paper, and iron wire, capable of simultaneously generating not only freshwater but also electricity from seawater. The 3D multi-walled carbon nanotubes/paper conical structure is an interconnecting link between steam and electricity generation, providing spacious surface area for both interfacial evaporation and oxygen reduction reaction (as a cathode of metal-air battery). The use of multi-walled carbon nanotubes not only secure high broadband light absorptance (~97% in UV–Vis-NIR) but also its conductivity is vital for efficient electricity generation. The device is capable of generating a power density of 13.50 W·m−2 while maintaining an evaporation rate of 1.53 kg·m-2·h−1 under 1 kW·m−2 solar illumination. In the current implementation, the energy density and built-in characteristics of the device, along with desalination capabilities can be a modest but invaluable solution for freshwater and energy needs in off-grid areas. [Display omitted] • A conical device is capable of generating freshwater and electricity from seawater. • The 3D MWNT/paper structure allows interfacial evaporation and oxygen reduction reaction. • The device demonstrates a power density of 13.50 W·m−2 and an evaporation rate of 1.53 kg·m-2·h−1 under 1 sun. • Adjusting the concentration or types of ions in seawater achieves higher electrical power. [ABSTRACT FROM AUTHOR]

[Display omitted] • RF plasma treatment increases the thickness of ITO film by enhancing the adhesion of the ITO layer. • RF plasma treatment during the sol-gel process reduces the sheet resistance of ITO film. • Oxygen vacancy decreased with increasing RF plasma treatment time. • ITO treated with RF plasma for 240 s showed the lowest sheet resistance of 126.5 Ω/sq. The argon atmospheric pressure plasma treatment is combined with the conventional sol-gel dip-coating process for fabricating ITO thin films to improve the electrical property of the ITO glass. The increase of the surface free energy of the ITO layer by plasma treatment improves the adhesion of the pre-annealed ITO layer, thereby increasing the thickness of the ITO film without significantly losing the light transmittance. While increasing the plasma treatment time up to 240 s, both the thickness and surface free energy of the ITO layer are increased, and the sheet resistance of the thin film is rapidly decreased. The ITO layer plasma-treated for 240 s with the thickness of 360 nm exhibits the lowest sheet resistance of 126.5 Ω/sq and the highest surface free energy of 79.45 mJ/m2. However, the increase of the plasma treatment time over 240 s do not affect the increase of film thickness, but the increase of sheet resistance. X-ray photoelectron spectroscopy depth profile reveals the decrease of the level of the oxygen vacancies with increasing plasma treatment time over 240 s. It results from the diffusion of oxygen from the surface into the bulk and explains the increase of the sheet resistance. [ABSTRACT FROM AUTHOR]

Putrescine and cadaverine are important volatile indicators for the evaluation of food spoilage. In this study, a metal-organic framework (MOF)-coated surface-enhanced Raman scattering (SERS) paper platform for the detection of putrescine and cadaverine is developed. Au@ zeolite imidazolate framework-8 (ZIF-8) SERS paper is fabricated by the coating of ZIF-8 layer on a Au nanoparticle-impregnated paper that is prepared by dry plasma reduction. The Au@ZIF-8 SERS paper is characterized by scanning electron microscope, energy-dispersive X-ray spectroscopy, X-ray diffraction, and N 2 sorption isotherm. The ZIF-8 layer enables the accumulation of gaseous molecules and also provides enhancement of SERS signals. The fluorescence, SERS, and simulation results prove the improved detection ability of the Au@ZIF-8 platform for the volatile molecules. For the selective detection of putrescine and cadaverine, the Au@ZIF-8 SERS paper is functionalized with 4-mercatobenzaldehyde (4-MBA). The 4-MBA molecule acts as a Raman reporter and also a specific receptor for the volatile amine molecules. Using the intensity ratiometric detection of 4-MBA-functionalized Au@ZIF-8 SERS paper, putrescine and cadaverine are quantitatively detected with detection limits of 76.99 and 115.88 parts per billion, respectively. Furthermore, the detection of volatile amine molecules released from spoiled salmon, chicken, beef, and pork samples is demonstrated. It is anticipated that the MOF-coated SERS paper platforms will be applicable not only in food safety but other applications including disease diagnosis and environmental monitoring. • MOF-coated SERS-active platform enables the detection of volatile amines from foodstuffs. • Putrescine and cadaverine are detected with high sensitivity and selectivity using Au@ZIF-8 SERS paper. • Au@ZIF-8 SERS paper is applied to the determination of food freshness for the first time. [ABSTRACT FROM AUTHOR]

Metal-assisted chemical etching (MACE) has been widely explored for developing silicon (Si)-based energy and optical devices with its benefits for low-cost and large-area fabrication of Si nanostructures of high aspect ratios. Surface structures and properties of Si nanostructures fabricated through MACE are significantly affected by experimental and environmental conditions of etchings. Herein, we showed that surfaces and interfacial energy states of fabricated Si nanowires can be critically affected by oxidants of MACE etching solutions. Surfaces of fabricated Si nanowires are porous and their tips are fully covered with lots of Si nano-sized grains. Strongly increased photoluminescence (PL) intensities, compared to that of the crystalline Si substrate, are observed for MACE-fabricated Si nanowires due to interfacial energy states of Si and SiOx of Si nano-sized grains. These Si grains can be completely removed from the nanowires by an additional etching process of the anisotropic chemical etching (ACE) of Si to taper the nanowires and enhance light trapping of the nanowires. Compared with the MACE-fabricated Si nanowires, ACE-fabricated tapered Si nanowires have similar Raman and PL spectra to those of the crystalline Si substrate, indicating the successful removal of Si grains from the nanowire surfaces by the ACE process. [ABSTRACT FROM AUTHOR]