Light-scattering Effect Research Articles

Photoactivity Enhancement of WO3 Photoanodes Using the Combined Effect of Plasmonic Au and Photoluminescent Y2O3:Eu3+ Nanoparticles.

The WO3 photoanode has great potential application for solar photoelectrochemical water oxidation due to suitable band edge positions with water oxidation potentials. However, it suffers from poor light absorbance in the visible region. Here, we use Eu3+-doped Y2O3 nanoparticles (NPs) in combination with plasmonic gold (Au) NPs to better utilize and adsorb photons from UV and visible regions of sunlight. We attached plasmonic Au NPs on WO3 to enhance the photocatalytic properties due to the plasmon resonance mechanism. Additional deposition of Y2O3:Eu3+ NPs on Au NPs/WO3 improved the photoactivity of the photoanode further. Y2O3:Eu3+ NPs' downconversion property, along with their light-scattering effect, converts ultraviolet-region photons into visible-region photons and enforces the plasmon resonance mechanism of Au NPs. Experimental results show the increase of absorbance, improvement of electron-hole separation, and enhancement in photocurrent generation of the resultant photoelectrode.

Layer-by-Layer Deposition of Hollow TiO2 Spheres with Enhanced Photoelectric Conversion Efficiency for Dye-Sensitized Solar Cell Applications.

Fabricating photoanodes with a strong light-scattering effect can improve the photoconversion efficiency of dye-sensitized solar cells (DSSCs). In this work, a facile microwave hydrothermal process was developed to prepare Au@TiO2 core-shell nanostructures, and then the Au core was removed by etching, resulting in hollow TiO2. Morphological characterizations such as field emission scanning and transmission electron microscopy measurements have been used for the successful formation of core-shell and hollow TiO2 nanostructures. Next, we attempted to deposit the different-sized hollow TiO2-based microspheres simultaneously on the surface of small-sized TiO2 nanoparticles-based compact film as light-scattering layers via electrophoretic deposition. The deposited hollow TiO2 microspheres constitute bi- and tri-layers that not only improve the light-harvesting properties but also speed up the photogenerated charge transfer. Compared to commercial TiO2 compact film (4.75%), the resulting bi-layer and tri-layered films-based DSSCs displayed power conversion efficiencies of 6.33% and 8.08%, respectively. It is revealed that the deposited bi- and tri-layered films can enhance the light absorption ability via multiple photon reflection. This work validates a novel and controllable strategy to develop light-scattering layers with increased light-harvesting properties for highly efficient dye-sensitized solar cells.

Efficiency enhancement of organic light-emitting diodes with multifunctional magnetic composite nanoparticles of Fe3O4@Au@SiO2

Multifunctional nanomaterials have been widely utilized to optimize the performances of optoelectronic devices. In this work, magnetic composite nanoparticles (NPs) of Fe3O4@Au@SiO2 are used as dopants to improve the quantum efficiency of electroluminescence of the tris-(8-hydroxyquinoline) aluminum-based organic light emitting devices (OLEDs). As a result, the performances of doped OLED (Von = 2.8 V, L = 23,400 cd/m2, EQE = 1.55) are obviously boosted as compared to the control device (Von = 2.9 V, L = 19,780 cd/m2, EQE = 1.27). Especially, the current efficiency of fluorescent green OLEDs can be 22.5 % enhanced by simply mixing the magnetic Fe3O4@Au@SiO2 (0.5 wt‰) NPs into poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), yielding the maximum value of 4.62 cd/A. The efficiency enhancement could be attributed to the collective effects of light-scattering, localized surface plasmon resonance (LSPR) and magnetic effect induced by magnetic composite NPs.

Investigating laser intensity profile and light scattering effects in the transmission laser welding process of 3D printed parts

Transmission Laser Welding (TLW) is a promising technique for joining thermoplastic and composite components, especially those produced through additive manufacturing or 3D printing processes. However, achieving optimal welding quality and efficiency in TLW of 3D printed parts is challenging due to the presence of highly heterogeneous and anisotropic materials, which introduce light scattering and absorption issues. Light scattering is caused by the refraction phenomenon. These phenomena significantly impact the laser intensity profile within the materials and at the welding interface, thereby affecting the energy required for successful welding and the mechanical strength of the final assembly. In this paper, we present an in-depth investigation into the laser intensity profile and the effects of laser-matter interaction on the welding of 3D-printed parts. Our approach combines experimental measurements using a heat flux sensor and an analytical inverse model to measure the laser intensity distribution within the materials at the welding interface. The results obtained from the experimental measurements and numerical identification are compared and analyzed, providing insights into the laser intensity profile in TLW of 3D printed parts.

Efficient Simulation of Light Scattering Effects in the Atmosphere

Efficient Simulation of Light Scattering Effects in the Atmosphere

Improving Determination of Pigment Contents in Microalgae Suspension with Absorption Spectroscopy: Light Scattering Effect and Bouguer-Lambert-Beer Law.

The Bouguer-Lambert-Beer (BLB) law serves as the fundamental basis for the spectrophotometric determination of pigment content in microalgae. Although it has been observed that the applicability of the BLB law is compromised by the light scattering effect in microalgae suspensions, in-depth research concerning the relationship between the light scattering effect and the accuracy of spectrophotometric pigment determination remains scarce. We hypothesized that (1) the precision of spectrophotometric pigment content determination using the BLB law would diminish with increasing nonlinearity of absorbance, and (2) employing the modified version of the BLB (mBLB) law would yield superior performance. To assess our hypotheses, we cultivated Phaeodactylum tricornutum under varying illumination conditions and nitrogen supplies in controlled indoor experiments, resulting in suspensions with diverse pigment contents. Subsequently, P. tricornutum samples were diluted into subsamples, and spectral measurements were conducted using different combinations of biomass concentrations and path lengths. This was carried out to assess the applicability of the BLB law and the nonlinearity of absorbance. The chlorophyll a and fucoxanthin contents in the samples were analyzed via high-performance liquid chromatography (HPLC) and subsequently used in our modeling. Our findings confirm our hypotheses, showing that the modified BLB law outperforms the original BLB law in terms of the normalized root mean square error (NRMSE): 6.3% for chlorophyll a and 5.8% for fucoxanthin, compared to 8.5% and 7.9%, respectively.

Ultrasensitive electrochemiluminescence sensor for the detection of synthetic cannabinoids based on perovskite as coreaction accelerator and light-scattering effects of photonic crystals

As is common knowledge, a strong electrochemiluminescence (ECL) signal is required to ensure the high sensitivity of trace target detection. Here, a dual signal amplification strategy by integrating of perovskite and photonic crystal was fabricated for quantitative synthetic cannabinoids (AB-PINACA) detection based on Zr-connected PTCA and TCPP (PTCA-TCPP) with excellent ECL performance as luminophores. On the one hand, the co-reaction accelerator perovskite (LaCoO3) improved the effective electroactive area of the electrode and promoted the decomposition of K2S2O8, resulting in a stronger ECL signal value. On the other hand, polystyrene inverse opal (PIOPCs) formed after the swelling of PS microspheres not only taken advantage of the light scattering effect and excellent catalytic property of photonic crystals to amplify the ECL signal, but also could be used as a binder to fix LaCoO3 and PTCA-TCPP on the electrode surface to generate unprecedented ECL response and stable ECL signals. Subsequently, the detection substance AB-PINACA was loaded on the electrode surface via the amide bond with the luminophores PTCA-TCPP, thus quenching the ECL signal, so as to realize the sensitive detection of synthetic cannabinoids. Under the optimal conditions, the proposed sensor achieved highly sensitive AB-PINACA detection with a dynamic range from 1.0 × 10−12 to 1.0 × 10−3 g/L and the detection limit was 1.1 × 10−13 g/L, which had great application potential in the detection of synthetic cannabinoids.

Study of the Scattering Effect by SiO2 Nanoparticles, in a Luminescent Solar Concentrator Sensitized with Carbon Dots.

Luminescent solar concentrators (LSCs) have become an attractive way to produce green energy via their integration into buildings as photovoltaic windows. Recently, carbon quantum dots (C-QDs) have become the most studied luminescent material for the manufacture of luminescent solar concentrators due to their advantages, such as low toxicity, sustainability, and low cost. Despite the advantages of carbon quantum dots, they remain a low-efficiency material, and it is difficult to fabricate LSCs with a good performance. To address this problem, some of the research has used SiO2 nanoparticles (Nps) to produce a light-scattering effect that helps to improve the system performance. However, these studies are limited and have not been discussed in detail. In this regard, this research work was designed to evaluate the contribution of the scattering effect in different systems of carbon quantum dots used in a possible luminescent solar concentrator. To carry out this study, C-QDs and SiO2 Nps were synthesized by hydrothermal methods and the Stober method, respectively. We used different concentrations of both materials to fabricate film LSCs (10 × 10 cm2). The results show that the light scattered by the SiO2 Nps has a double contribution, in terms of light redirected towards the edges of the window and as a secondary source of excitation for the C-QDs; thus, an improvement in the performance of the LSC is achieved. The best improvement in photoluminescence is achieved when the films are composed of 20% wt carbon quantum dots and 10% wt SiO2 Nps, reaching a gain of 16% of the intensity of the light incident on the edges of the window with respect to the LSCs where only C-QDs were used.

Use of an Integrating Cavity Spectrometer to Easily Determine Beer SRM Color Without Filtration, Centrifugation or Numerical Correction

Quantification of beer color of craft unfiltered, hazy, seltzer, and fruited beer styles can be problematic due to turbidity and unconventional ingredients. A novel integrating cavity spectrometer (ICS), designed to eliminate the effect of light scatter by the sample was employed to determine if it was able to more accurately quantify beer color compared to a conventional scanning spectrophotometer (CSS). A CSS was employed to measure the absorbance and transmission of 15 filtered and unfiltered craft brewery beer samples to determine the SRM color value and tristimulus color values. The ICS measures absorbance with a 430 nm LED to determine the single-point SRM value for each beer. The SRM values of unfiltered or 0.2 µm filtered beer samples were compared using Bland-Altman analysis and regression fits. Filtered and very clear beers showed strong agreement between the methods and Bland-Altman analysis confirmed their equivalence, particularly for SRM <25. Using the ICS alone, filtered beer versus unfiltered beer showed highly correlated values and narrow limits of agreement, successfully negating the effects of turbidity. In conclusion, SRM determination by ICS is equivalent to standard spectrophotometer single-point methods and superior in accurately determining the SRM color of hazy beers without filtration or centrifugation.

Enhanced photocatalytic activity of S-doped graphitic carbon nitride hollow microspheres: Synergistic effect, high-concentration antibiotic elimination and antibacterial behavior

For the past few years, graphitic carbon nitride (g-C3N4) has been widely used to eliminate environmental pollutants, but limited active site on surface and low separation/migration ability suppress its practical uses. Herein, we adopted a supramolecular self-assembly route followed with S doping to synthesize S-doped g-C3N4 with a hollow microsphere composition (SCNHM), where the shell was demonstrated to compose of ultrathin nanosheets. The unique structural characteristics endow the SCNHM with high specific surface area (∼81 m2 g−1) to provide abundant reaction sites and enhanced light-harvesting due to the light-scattering effect of hollow structure. Moreover, the S dopant meliorated the electronic structure to narrow the bandgap and promoted the charge separation/transfer capability. With this synergistic effect, the SCNHM presented greatly improved photocatalytic activity for degrading tetracycline hydrochloride (TC) compared to the CN, SCN and CNHM samples. This photocatalyst could eliminate high-concentration TC (50 mg L−1) in 18 min, and the 30 min removal efficiencies of 100 mg L−1 and 200 mg L−1 reached 92 % and 60 %, which is much better than the reported photocatalysts in literatures (usually ≤ 20 mg L−1). Additionally, the good photocatalytic durability was confirmed and the degradation pathway of TC was proposed. Furthermore, the SCNHM was proved to meanwhile possess superior performance for inactivating the typical Gram-positive bacterium of Staphylococcus aureus (S. aureus) and the typical Gram-negative bacterium of Escherichia coli (E. coli). Finally, based on determination of band alignment and detection of active species, a plausible photocatalytic mechanism was proposed.

Towards improved efficiency of SnS solar cells using back grooves and strained-SnO2 buffer layer: FDTD and DFT calculations

In this work, a novel SnS thin-film solar cell (TFSC) based on strained-SnO2 electron transport layer (ETL) combined with back grooves aspect is proposed. The density functional theory (DFT) is used to assess the influence of the unit cell volume engineering on the electronic and optical properties of SnO2 material. Simulated results demonstrate the potential of strained-SnO2 material as a junction partner of p-type SnS absorber, showing a favorable conduction band offset and thereby reduced recombination effects. Moreover, the role of back grooves texture in enhancing light-scattering effects is investigated using FDTD technique. It is revealed that the proposed SnS TFSC based on combined strained-SnO2/SnS heterostructure and optimized back grooves paradigm offers the possibility for bridging the gap between improved absorption capabilities and enhanced photo-induced carrier extraction characteristics. It is demonstrated that the optimized SnS TFSC exhibits superior performances compared to the conventional one in terms of photovoltaic parameters, offering a high short-circuit current of Isc = 28 mA/cm2, a superior open-circuit voltage of Voc = 0.47 V, a high fill factor of FF = 68.4% and over than 9% of PCE. Therefore, our work paves the way to use the strained-SnO2 buffer layer and back grooves to boost the poor performances of SnS-based TFSCs.

Low Serum Bicarbonate in a Patient With Diabetes Mellitus:: A Quiz

Low Serum Bicarbonate in a Patient With Diabetes Mellitus:: A Quiz

A Sensitive Electrochemiluminescence Urea Sensor for Dynamic Monitoring of Urea Transport in Living Cells.

A multiple signal-amplified electrochemiluminescence (ECL) urea sensor was designed based on a self-enhanced probe and SiO2 photonic crystals for dynamic tracking of urea transmembrane transport. The self-enhanced probe (AuNR@Ru-LA) prepared by loading polyethyleneimine (PEI), lactobionic acid (LA), and Ru(dcbpy)32+ on gold nanorods (AuNRs) generated an initial ECL signal, and then the intensity was multiple-amplified by the enhanced light-scattering effect of SiO2 photonic crystals and the co-reaction with urea. The as-prepared sensor exhibited excellent performance for the detection of urea in the range of 1.0 × 10-10 to 1.0 × 10-4 M with a detection limit of 8.8 × 10-11 M at (3σ)/S. The AuNR@Ru-LA probes were labeled on HepG2 cells to construct a cytosensor with a detection range of 1.0 × 103 to 2.0 × 106 cells mL-1. In addition, the dynamic changes of the extracellular urea concentration were tracked by monitoring the ECL signal of the cytosensor to study urea transmembrane transport. The developed strategy realized the amplification of multiple ECL signals and the tracking of urea transmembrane transport, which provided a novel dynamic detection method for small biomolecules.

Fabrication of Barium Titanate Nanowires-GNP Composite Bilayer Photoanodes for the High-Performance Dye-Sensitized Solar Cells

Inorganic perovskite barium titanate nanowires (BTNWs) and their nanocomposites comprised of different weight percentages (1, 2, and 3 wt%) of graphene nanoplatelets (GNP) are synthesized via a hydrothermal method and used as photoanode materials of dye-sensitized solar cells (DSSCs). Morphological analysis of the BTNWs and BTNWs + GNP composites has indicated that the one-dimensional BTNWs and two-dimensional GNP are formed as uniformly distributed, well-connected mesoporous microstructures. UV–visible absorption and Raman studies of the BTNWs + GNP composites have revealed a narrowing bandgap, improved visible light absorption with increasing GNP content, and a superior light-scattering effect of BTNWs. Besides, four different DSSC bilayer photoanodes comprising titanium dioxide nanoparticles (TNP) underlayer and an upper layer with BTNWs + (0, 1, 2, and 3 wt%) GNP composites are fabricated to elucidate the TNP + BTNWs and BTNWs + GNP composite sublayer(s) influences on the photovoltaic performance. The TNP + BTNWs + 2 wt% GNP composite bilayer photoanode has demonstrated a higher power conversion efficiency of 9.92 % as compared to that of the other TNP + BTNWs + GNP composite bilayer photoanodes in DSSCs, due to the higher charge recombination resistance, faster charge transport, superior charge collection ability and carrier lifetime of its sublayers.

Super-hydrophilic SERS sensor with both ultrahigh activity and exceptional 3D spatial uniformity for sensitive detection of toxic pollutants

The powerful surface-enhanced Raman scattering spectroscopy (SERS) practical technique is not only related to signal enhancement but also heavily dependent on spatial uniformity. Different from the routine hydrophobic substrates, an extraordinary super-hydrophilic SERS sensor is established by loading plasmonic Au nanoparticles (NPs) on two-dimensional (2D) hexagonal boron nitride (h-BN) then the hybrids uniformly are grafted into 3D bacterial nanocelluloses (BNCs). The Au NPs@h-BN/BNCs exhibit a remarkably high SERS activity with a limit of detection (LOD) of dyes at 0.1 femtomole (fM) level (∼10-16 M). It is attributed to the strong synergistic coupling effect between highly dense Au NPs and modified h-BN as well as multiple light-scattering effects in 3D porous supports. More importantly, the distinctive advantage is further highlighted by the exceptional 3D spatial SERS uniformity with relative standard deviation (RSD) less than 3.4% along both horizontal and vertical directions. The unique feature is due to the 3D homogeneous distribution of the injected colloidal analytes via ultra-rapid liquid diffusion throughout the entire body with superior wettability. Besides, the flexible SERS substrates with excellent easy-tailorable mechanical properties can be robust enough to withstand the portable operations in real-world scenarios. These competitive merits are particularly beneficial for reliable SERS quantitative surveillance.

Surface Plasmon Resonance and Increased Interfacial Electron Transfer of 3D AgNWS@TiO2NS Structure for Enhanced Photocatalytic and DSSC Properties

Ag nanowires coated with TiO2 nanosheets (AgNWS@TiO2NS, AWT) have been successfully synthesized via a one-pot hydrothermal synthesis. Importantly, the prepared AWT shows enhanced photocatalytic activity compared with Degussa P25, which is attributed to its continuous hierarchical structures, special conductive channel and localized surface plasmon resonance (SPR). Additionally, these prepared AWT were exploited as an electron conductor and scattering material in the TiO2 composite photoanodes of dye-sensitized solar cells (DSSCs). The highest energy conversion efficiency of 6.98% was achieved when the AWT doping rate in the photoanode slurry was 5 wt%. Both enhanced Isc and Voc are attributed to the increased photo-absorption efficiency from the localized SPR. The potential enhanced light-scattering effect and faster photoelectric transmission efficiency of the AWT in the photoanode.

Hollow performances quenching label of Au NPs@CoSnO3 nanoboxes-based sandwich photoelectrochemical immunosensor for sensitive CYFRA 21-1 detection

In this work, a fire-new “signal-off” type photoelectrochemical (PEC) immunosensor based on bismuth sulfide/iodine doped bismuth oxychloride (Bi2S3/I:BiOCl) heterostructure as a platform and Au nanoparticles loaded hollow CoSnO3 nanoboxes (Au NPs@CoSnO3) as quenching label was designed, for sensitive detection of CYFRA 21-1. The I:BiOCl with flower-like structure could supply high specific surface area for loading nanometer materials. Then, Bi2S3 was formed in-situ by S2− adsorption on the surface of I:BiOCl by dangling bond of Bi3+, but did not change the flower-like structure of I:BiOCl. Then, n-type Bi2S3 and p-type I:BiOCl heterostructure showed good photoelectric behavior by providing an additional electric field to accelerate electron-hole separation. Furthermore, the production process of the heterostructure was simple, fast, low temperature, and without complex raw materials. The Au NPs@CoSnO3 with good photocatalytic activity could strongly compete with Bi2S3/I:BiOCl for electron donor of ascorbic acid (AA). Meanwhile, the CoSnO3 with hollow structure made the quenching effect more significant by the light-scattering effect that enhanced the light absorption capacity and shorten distance of carrier transport. Under optimal conditions, this proposed strategy displayed the low detection limit of 30 fg/mL, with a high linearity range from 100 fg/mL to 100 ng/mL for tumor markers CYFRA 21-1. Simultaneously, it also exhibited excellent specificity and acceptable stability, which might provide a new perspective for the fabrication of other PEC immunosensors with heterostructure simple synthesis and hollow materials.

Enhanced Photocatalytic Water Decontamination by Micro-Nano Bubbles: Measurements and Mechanisms.

Despite recent advancements in photocatalysis enabled by materials science innovations, the application of photocatalysts in water treatment is still hampered due to low overall efficiency. Herein, we present a TiO2 photocatalytic process with significantly enhanced efficiency by the introduction of micro-nano bubbles (MNBs). Notably, the removal rate of a model organic contaminant (methylene blue, MB) in an air MNB-assisted photocatalytic degradation (PCD) process was 41-141% higher than that obtained in conventional macrobubble (MaB)-assisted PCD under identical conditions. Experimental observations and supporting mechanistic modeling suggest that the enhanced photocatalytic degradation is attributed to the combined effects of increased dissolution of oxygen, improved colloidal stability and dispersion of the TiO2 nanocatalysts, and interfacial photoelectric effects of TiO2/MNB suspensions. The maximum dissolved oxygen (DO) concentration of the MNB suspension (i.e., 11.7 mg/L) was 32% higher than that of an MaB-aerated aqueous solution (i.e., 8.8 mg/L), thus accelerating the hole oxidation of H2O on TiO2. We further confirmed that the MNBs induced unique light-scattering effects, consequently increasing the optical path length in the TiO2/MNB suspension by 7.6%. A force balance model confirmed that a three-phase contact was formed on the surface of the bubble-TiO2 complex, which promoted high complex stability and PCD performance. Overall, this study demonstrates the enhanced photocatalytic water decontamination by MNBs and provides the underlying mechanisms for the process.

Absorption enhancement in amorphous Si by introducing RF sputtered Ti intermediate layers for photovoltaic applications

In this paper, embedded amorphous-silicon (a-Si) and titanium (Ti) ultrathin-films forming a multilayer structure is proposed as a new efficient absorber material for thin-film solar cells (TFSCs). Promising design strategy based on combining FDTD (finite difference time domain) with particle swarm optimization (PSO) was adopted to identify the a-Si/Ti multilayer structure offering the highest total absorbance efficiency (TAE). It is found that the proposed multilayer structure can serve as an effective absorber, yielding superb TAE exceeding 80%. The a-Si/Ti multilayer was then elaborated by successive growth of a-Si and Ti ultrathin layers using RF magnetron sputtering technique. The sputtered a-Si/Ti thin-film was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV–visible absorption spectroscopy. Measurements showed a unique optical behavior, promoting broadband absorbance over the visible and even NIR spectrum ranges. In particular, the prepared a-Si/Ti absorber exhibits an optical band-gap of 1.36 eV, which is suitable for photovoltaic applications. A performance assessment of the elaborated absorber was investigated by extracting I-V characteristics and electrical parameters under dark and 1-sun illumination. It is revealed that the proposed absorber demonstrates outstanding electrical and sensing performances. Therefore, promoting enhanced resistive behavior and light-scattering effects, this innovative concept of optimized a-Si/Ti multilayer provides a sound pathway for designing promising alternative absorbers for the future development of a-Si-based TFSCs.

Microstructured ZnO-ZnS composite for earth-abundant photovoltaics: Elaboration, surface analysis and enhanced optical performances

In this paper, ZnO-ZnS composite structure is proposed as a new efficient and earth-abundant absorber material for thin-film solar cells (TFSCs). Promising elaboration strategy based on combining vacuum thermal evaporation technique and oxidation process under an annealing temperature of 500 °C was used to prepare ZnO-ZnS composite with high sun-light absorption capabilities. The fabricated microstructure was then characterized by Scanning Electron Microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and UV–Visible absorption spectroscopy. The influence of the annealing time on the structural and optical performances of the prepared samples was investigated. Surface analysis demonstrated the ZnO decoration of ZnS thin-film, where SEM images showed dense and pinhole-free ZnO-ZnS composite with micrometer-sized grains and a few voids visible at thin-films surface. Optical characterization showed that the prepared thin-film absorber exhibits an optical band-gap of 2.65 eV with a high Total Absorption Efficiency (TAE) of 62% and an absorption coefficient exceeding 2 × 104 cm−1. In addition, I-V characteristics under dark and 1-sun illumination of the microstructured ZnO-ZnS composite were extracted. It was revealed that the proposed absorber showcases a high visible photoresponse. Therefore, promoting effective light-scattering effects, this innovative ZnO-ZnS composite offers a sound pathway to prepare alternative low-cost absorbers for the future development of TFSCs.