Eosin Y Research Articles

Novel Strategy of Constructing Artificial Light-Harvesting System with Two-Step Sequential Energy Transfer for Efficient Photocatalysis in Water.

An efficient artificial light-harvesting system with a two-step sequential energy transfer was fabricated in the aqueous solution based on the host-guest interactions between cyano-substituted p-phenylenevinylene derivative (PPTA) and a water-soluble pillar[5]arene (WP5). PPTA-WP5 complex could self-assemble into nanoparticles, and two fluorescent dyes eosin Y (EY) and Nile Red (NIR) are employed as acceptors to realize sequential energy transfer. The PPTA-WP5-EY-NIR system could achieve efficient two-step sequential energy transfer process from PPTA-WP5 to EY and then to NIR (67% for the first step and 66% for the second step). Moreover, to make full use of the harvested energy, the hydrophobic microenvironment in the assembled nanoparticles is used to promote the aerobic cross-dehydrogenative coupling (CDC) reaction in aqueous medium with 88% yield after 12 h of irradiation. To our knowledge, this is the first example of artificial LHS with two-step energy transfer used to catalyze the CDC reaction in aqueous medium. This work directly mimics the function of photosynthesis in nature of converting solar energy into chemical energy in aqueous solution.

Double‐Network Confined Supramolecular Phosphorescence Light‐Harvesting Boosting Photocatalysis

AbstractA double‐network phosphorescence light‐harvesting (PLH) supramolecular system is successfully fabricated based on synergistic confinement strategy. First, the bicationic vinyl bromophenyl pyridine derivative (G) is encapsulated by cucurbit[8]uril (CB[8]), inducing weak phosphorescence emission at 510 nm. Subsequently, the G/CB[8] is confined by in situ copolymerization with acrylamide, displaying enhanced phosphorescence emission, then coassembled with hyaluronic acid modified hydroxypropyl‐β‐cyclodextrin (HA‐HP‐β‐CD) to form double‐network hydrogel, further improving phosphorescence lifetime from 442 µs upto 5.17 ms. Benefitting from the confinement of double‐network of supramolecular system, the doped Eosin Y (EY) as acceptor can be photosensitized by the phosphorescence of G/CB[8] leading to delayed fluorescence emission of EY with long lifetime as 36.4 µs. As compared with EY alone, by the synergistic effect of the confined microenvironment and long lifetime photosensitizer, the PLH system is successfully applied in cross‐coupling reaction and exhibits enhanced activity, providing a new strategy for the application of phosphorescence energy transfer boosting photocatalysis.

Photocatalytic hydrogen evolution performance of metal ferrites /polypyrrole nanocomposites

The combination of inorganic (e.g., ferrite nanoparticles) and organic (e.g., conducting polymers) materials in the fabrication of heterojunctions or composites is an attractive scheme in the field of photocatalysis. We took the advantage of this phenomenon by fabricating MFerrite (M = Co, Ni, and Zn) @polypyrrole (MFerrite@Ppy) nanocomposites with a varying weight percentage of Ppy for the hydrogen production through photocatalytic water splitting under visible light irradiation. The structural, spectral, morphological, compositional, and optical features of the as-prepared nanocomposites were analyzed in full depth. The average crystallite sizes were estimated to be 30–40 nm from the XRD patterns which were further validated by TEM images from which a core-shell structure of the composites can be inferred. Likewise, the SEM images revealed spherical Ppy particles with a diameter in the range of 100–300 nm. From a photocatalytic viewpoint, CoFerrite@30Ppy is endowed with some peculiar characteristics including but not limited to strong light-harvesting ability (ranging between 300 and 650 nm), narrow optical band gap (as low as 1.6 eV), and higher photoluminescence (PL) lifetime (6.41 ns) which justify why it stands out among all composites in terms of photocatalysis. Under 8 h illumination of simulated visible light and using triethanolamine (TEOA) as a hole scavenger and Eosin-Y (EY) as a dye sensitizer, the photocatalytic hydrogen evolution (HER) amount for CoFerrite@30Ppy was found to be 10.44 mmol g−1, far greater than any other composite catalysts in this study. From the PL spectra, it can be pointed out that sensitization of CoFerrite with 30 wt % Ppy conduces to simultaneous deceleration of the electron-hole recombination process and acceleration of the transference of excitons within the system.

Synergy of heterojunction and interfacial strain for boosting photocatalytic H2 evolution of black phosphorus nanosheets

As an emerging post-graphene two-dimensional material, black phosphorus (BP) has attracted enormous interest as a promising cocatalyst for photocatalytic hydrogen (H2) evolution, however, the activity of either pristine bulk or BP nanosheets is far from satisfactory. Herein, we present an effective strategy to greatly boost the H2 evolution performance of BP via applying the synergistic effect of heterojunction and interfacial lattice strain. A multilayered heterostructure coupling BP nanosheets and nickel oxide (NiO) nanosheets with abundant interface P-Ni and PO bonds is synthesized and utilized as a proof-of-concept material for our design. Both the experimental and theoretical results have revealed that the strain is formed in BP-NiO multilayered heterostructure. The generated lattice strain induces the charge redistribution at the interface between BP and NiO, which leads to the improved electron transfer efficiency and favorable H* adsorption kinetics for photocatalytic H2 evolution reaction. As a result, the BP-NiO heterostructure with strain effect exhibits much enhanced photocatalytic H2 evolution activity in the presence of Eosin Y (EY) as photosensitizer, exceeding that of zero-strained BP/NiO heterostructure and many other reported noble-metal-free cocatalyst.

Micro-Scale Laser-Induced Fluorescence Thermometry For Multiphase Flow Of Immiscible Liquids

In this work an implementation of laser induced fluorescence thermometry technique at the micro-scale for application in multiphase flow of two immiscible liquid is presented. The selected fluid phases are water and n-decane. One key limiting factor for dye selection is that each dye must be soluble in only one of the liquid phases. The selected fluorescent dyes are sulforhodamine 101 (SR) and eosin Y (EY) in water, and pyrromethene 597-8C9 in n-decane. The technique uses ratiometric two-color two-dye approach for water and two-color one-dye approach for n-decane. The two imaging wavelength bands are 540–572 nm and 610–640 nm. The technique yields a measurement sensitivity of 1.7% K^{-1} in water and ~0.1% K^{-1} in n-decane in the temperature range 20–60 ºC with a spatial and temporal resolution of 5.2 µm and 1 s, respectively. The sensitivity and uncertainty level achieved herein are satisfactory and near expected values for the aqueous phase. For the non-aqueous phase, modifications in the optical setup and/or choice of fluorescent dye(s) are needed to improve the sensitivity of the measurement technique.

Photocatalytic Activity of Orchid-Flower-Shaped ZnO Nanoparticles, toward Cationic and Anionic Dye Degradation under Visible Light, and Its Anti-Cancer Potential

Orchid-flower-shaped ZnO nanomaterials were successfully synthesized via green synthesis and an eco-friendly approach using an aqueous extract of Lycium chinense fruit as a reducing and capping agent. The synthesized Lycium chinense orchid-flower-shaped ZnO (LC-ZnO/OF) nanoparticles (NPs) were characterized using different analytical methods through X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), photoelectron spectroscopy (XPS), and photoluminescence (PL). The FE-TEM analysis revealed the orchid flower shape of the nanoparticles, and the elemental composition was confirmed via XPS analysis. The photocatalytic activity of the nanoparticles was determined by the degrading cationic dye methylene blue (MB) and the anionic dye Eosin Y (EY) under visible light irradiation at (400 w) within 180 min time, where it showed a significant ability to degrade both cationic and anionic dye by almost 50%. The LC-ZnO/OF photocatalyst was also used to check the toxicity level in human cancer cells, where it exhibited remarkable cytotoxicity to the human lung cancer (A549 cell line) and human gastric adenocarcinoma hyperdiploid (AGS cell line). The present investigation suggests that LC-ZnO/OF has the potential photocatalytic ability to degrade toxic dye as well as have anti-cancer effects. These preliminary results suggest that LC-ZnO/OF could have a significant impact on the environmental and biomedical fields.

UiO-66 with confined dyes for adsorption and visible-light photocatalytic reduction of aqueous Cr(VI)

• Dye molecules confined in MOFs for continuous and stable photosensitization in a photocatalytic reaction. • Photocatalytic reduction of Cr(VI) in water at neutral pH without any sacrificial reagent. • Adjustment on surface electrostatic properties of UiO-66 by dye confinement and loading of Pt nanoparticles. • A simple and feasible method to enhance the visible-light photocatalytic ability of a MOF. Dye sensitization is an important method to improve the visible-light response of a photocatalyst. In order to obtain stable dye-sensitized MOF photocatalysts, UiO-66 with confined rhodamine B (RhB) and eosin Y (EY) dye were prepared by simply adding dyes in the synthetic process in this work. In comparison with pristine UiO-66, the obtained RhB@UiO-66 and EY@UiO-66 can not only adsorb Cr(VI) from water more effectively, but also enhance the photocatalytic reduction of Cr(VI) to Cr(III) at a neutral pH under visible-light without adding any sacrificial agent. Thus, they both achieved an overall Cr(VI) removal rate of about 99%. The loading of Pt nanoparticles can further improve the photocatalytic abilities of RhB@UiO-66 and EY@UiO-66. The highest photocatalytic removal rate of Cr(VI) over Pt/RhB@UiO-66 is 66.4%. The confinement of the dyes and the loading of Pt nanoparticles largely changed the surface electrostatic properties of UiO-66. The adsorption process of Cr(VI) was therefore affected. Meanwhile, Pt nanoparticles greatly improved the utilization efficiency of photogenerated electrons.

Smartphone-assisted paper-based multifunctional assay for on-site tandem detection of inorganic phosphate, neutral red and heparin

Today, easy availability and efficient detection assays in low-resource settings are mandatory. Therefore, a smartphone-assisted paper-based detection strategy using eosin Y (EY)-embed ZIF-8 nanocomposite for phosphate (Pi), neutral red (NR) and heparin (HP) on site testing was fabricated. After adding the targets in a specific order, the prepared strips produced brilliant color transitions (astonishing colors, ranging from pistachio to bright yellow for Pi, from bright yellow to jacinth for NR and from jacinth to light orange for HP). These variation on tonality can be evaluated by the smartphone-based readout device (Color Assist App) through the ratio change of B/(R + G + B), which exhibits superior performance of on-site detection in wastewater, including high sensitivity (LOD is 0.015, 0.031 and 0.014 mM for Pi, NR and HP, respectively), ultra-fast response time and excellent selectivity. This strips and smartphone dual-mode monitoring strategy may offer a convenient idea to identify Pi, NR and HP, with great prospects for environmental wastewater applications. Additionally, the probe was enabled for bioimaging of Pi, NR and HP in living cells. Finally, the related anti-counterfeiting fluorescent ink of probe was proposed on schedule.

Two-step, sequential, efficient, artificial light-harvesting systems based on twisted cucurbit[14]uril for manufacturing white light emission materials

White-light-emitting (WLE) materials have promising and valuable applications in controllable lighting, screen displays and sensing. In this study, a two-step sequence of highly efficient artificial light-harvesting systems (ALHSs) with white light emission is successfully constructed in the aqueous phase through a non-covalent bond among imidazole derivatives (DIm), twisted cucurbit[14]uril (tQ[14]), eosin Y (ESY), and Nile red (NiR). The prepared linear supramolecular polymer (DIm@tQ[14]) constructed by DIm and tQ[14] through host–guest interaction is an ideal energy donor due to its superior aggregation-induced emission effect, which enables one-step energy transfer by loading ESY and two-step energy transfer by further loading NiR with a high efficiency of 91.47%. The emission color of the two-step sequential ALHSs changes from cyan to chartreuse then to orange-red, and bright white light emission can be achieved by controlling the donor/acceptor molar ratio. Moreover, the assemblies of the two-step sequential ALHSs can be applied to white LED materials. This research not only simulates the multi-step energy transfer process in nature but also has an attractive commercial value in the manufacturing of WLE materials.

Graphite Counter Electrode for Cost Effective Dye Sensitized Solar Cells (DSSCs)

Hydrothermally synthesized TiO2 nanoparticles were coated onto FTO glass plates and sensitized with Eosin Y (EY) dye. The graphite counter electrode (G) was fabricated by G coating onto the Al and then the cells were assembled by sandwiching the TiO2 photo anode (soaked in EY) and the counter electrode. The assembled FTO/TiO2+EY/Electrolyte/GCE solar cells were subjected to I-V characteristics under a light source of 100mW/cm2. I-V measurement was carried out for Pt CE, and for the G CE based DSSCs. The result cell with Pt CE shows high open circuit voltage (VOC ) 0.717V and fill factor (FF) 0.51, where the G CE based cell gives short circuit current (ISC ) 1.4 mA and photo conversion efficiency (η) 0.56%. Finally, the cell which is fabricated with G counter electrode shows better performance than the Pt CE based cell.

Tetraphenylethylene-embedded pillar[5]arene-based orthogonal self-assembly for efficient photocatalysis in water.

Herein, we have designed and fabricated a simple and efficient supramolecular self-assembled nanosystem based on host–guest interactions between water-soluble tetraphenylethylene-embedded pillar[5]arene (m-TPEWP5) and ammonium benzoyl-ʟ-alaninate (G) in an aqueous medium. The obtained assembly of m-TPEWP5 and G showed aggregation-induced emission (AIE) via the blocking of intramolecular phenyl-ring rotations and functioned as an ideal donor. After the loading of eosin Y (EsY) as acceptor on the surface of the assembly of m-TPEWP5 and G, the worm-like nanostructures changed into nanorods, which facilitates a Förster resonance energy transfer (FRET) from the m-TPEWP5 and G assembled donor to the EsY acceptor present in the nanorod assembly. The system comprising m-TPEWP5, G and EsY displayed moderate FRET efficiency (31%) at a 2:1 molar ratio of donor-to-acceptor. Moreover, the obtained supramolecular nanorod assembly could act as a nanoreactor mimicking natural photosynthesis and exhibited a high catalytic efficiency for the photocatalytic dehalogenation reaction of various bromoketone derivatives with good yields in short reaction time in water.

Construct 3D NiCo-LDH/Cu2O p-n heterojunction via electrostatic self-assembly for enhanced photocatalytic hydrogen evolution

Hydrogen evolution of inorganic photocatalysts is currently a hot research topic. In order to prepare highly efficient catalysts for hydrogen evolution, p-n type heterojunctions were successfully constructed by closely combining p-type Cu2O and n-type NiCo-LDH with opposite electrical properties by a simple electrostatic self-assembly. In addition, because the positions of the two single catalysts NiCo-LDH and Cu2O Fermi levels are dissimilar from those of traditional p-n heterojunctions, the extremely high movement of Fermi levels forms a strong built-in electric field, which powerfully prevents the gradient diffusion of charge and facilitates the migration of intrinsic photocarriers. Furthermore, the flower cluster NiCo-LDH is composed of two-dimensional thin sheet structure, which has a large specific surface area and can prevent Cu2O agglomeration. Under the condition of using triethanolamine solution and eosin Y (EY) respectively as sacrifice reagent reducing agent and photosensitizer, the composite catalyst has reached 18332 μmol·g−1 in 5 h, which was increased by 8.5 times compared to the pure Cu2O. This research provides an innovative strategy to construct a heterojunction between a metal double-layer hydroxide and a non-noble metal oxide to realize an effective photocatalytic hydrogen production.

Performance analysis of aqueous Al-ion electrolyte based dye sensitized solar cell

Photovoltaic performance of the aqueous Al-ion electrolyte-based dye-sensitized solar cells (DSSCs) was investigated by varying the aluminium nitrate concentration, ranging from 0.02 to 0.1 M and using Eosin-Y (EY) sensitized antimony-doped tin oxide (ATO) photoanode with platinum (Pt) as counter electrode. Photoconversion efficiency (PCE) peaks for 0.1 M using the source of 100 mW cm−2 with AM 1.5G (standard) solar simulator under ambient condition, photocurrent density (JSC) reaches 3.76 mA/cm2 and efficiency (PCE, η) 3.17%. Most of the work that exist in literature with (K, Na, Co, Li, etc. based) aqueous electrolyte quoted the maximum efficiency 1.55% whereas, the present work with pure aqueous Al-ion electrolyte gives 50% of higher efficiency over the quoted value. Moreover compared to the undoped tin oxide photoanode, this work with Sb doped tin oxide shows an enhancement of efficiency about 80%.

Naphthalenyl-phenylacrylonitrile-based supramolecular aqueous artificial light-harvesting system for photochemical catalysis

Highly efficient aqueous artificial-light-harvesting systems (ALHSs) were successfully fabricated based on the supramolecular assembly of naphthalenyl-phenylacrylonitrile derivative (NPT), water-soluble pillar [5]arene (WP5), and three kinds of pigments (4,7-di(2-thienyl)-2,1,3-benzothiadiazole (DBT), Eosin Y (ESY), and sulforhodamine-101 (SR101)). The assembled ALHSs perform a high energy-transfer-efficiency (ΦETE) and antenna effect (90.9% and 40.6 for WP5⊃NPT-DBT, 81.5% and 39.1 for WP5⊃NPT-ESY as well as 71.3% and 38.4 for WP5⊃NPT-SR101), suggesting that the energy of WP5⊃NPT complex has been effectively transferred to pigment acceptors (DBT, ESY, and SR101). Notably, during the energy-transfer process of WP5⊃NPT-SR101 ALHS, a white light emission (ΦQY = 24.21%) could be achieved by tuning the molar-ratio of [NPT]/[SR101] to 250:1, which is close to that of natural light-harvesting system, displaying a promising application in simulating natural light-harvesting system. Furthermore, the WP5⊃NPT-SR101 ALHS was successfully utilized as nanoreactors to catalyze the free-radical dehalogenation reactions of 2-bromo-acetophenone, 2-bromo-4′-methylacetophenone, and 2-bromo-4′-nitroacetophenone with the yields of 92%, 90% as well as 95%, which realized the energy transformation from solar-energy to chemical-energy, displaying a potential prospect in the field of artificial photosynthesis systems.

Emissive Platinum(II) Macrocycles as Tunable Cascade Energy Transfer Scaffolds.

Developing artificial light-harvesting scaffolds with a cascade energy transfer process is significant for better understanding of photosynthesis. Here, we report [3+3] self-assembled PtII fluorescent macrocycles (3 a and 3 b) as light-harvesting platforms with cascade energy transfer. The PtII macrocycles aggregate into nanospheres and show emission-enhancement characteristics upon increasing water content in acetone medium. These aggregates (3aa and 3ba ) serve as energy donors when mixed with the hydrophobic dye Eosin-Y (ESY). In the presence of a second dye, Nile Red (NiR), an unusual sequential two-step energy transfer takes place from the macrocycles to NiR. In this case, ESY acts as a bridge in the relay mode. Additionally, a unique strategy to control such an energy transfer process by tuning the chain length of the alkyl group attached to the periphery of the macrocycles is demonstrated.

Emissive Platinum(II) Macrocycles as Tunable Cascade Energy Transfer Scaffolds

AbstractDeveloping artificial light‐harvesting scaffolds with a cascade energy transfer process is significant for better understanding of photosynthesis. Here, we report [3+3] self‐assembled PtII fluorescent macrocycles (3 a and 3 b) as light‐harvesting platforms with cascade energy transfer. The PtII macrocycles aggregate into nanospheres and show emission‐enhancement characteristics upon increasing water content in acetone medium. These aggregates (3aa and 3ba) serve as energy donors when mixed with the hydrophobic dye Eosin‐Y (ESY). In the presence of a second dye, Nile Red (NiR), an unusual sequential two‐step energy transfer takes place from the macrocycles to NiR. In this case, ESY acts as a bridge in the relay mode. Additionally, a unique strategy to control such an energy transfer process by tuning the chain length of the alkyl group attached to the periphery of the macrocycles is demonstrated.

PH-Responsive Amphoteric p (APTMACl-co-AMPS) Hydrogel as Effective Multiple Dye Sponge Network From Aqueous Media

Here, the cationic poly (3-acrylamidepropyl trimethyl ammonium chloride) [p (APTMACl)], anionic poly (2-acrylamido-2methylpropane sulfonic acid) [p (AMPS)], and amphoteric poly (APTMACl-co-AMPS) hydrogels were prepared via free-radical polymerization techniques as pH-sensitive hydrogels. The prepared systems were used in methylene blue (MB), and Eosin Y (EY) removal from aqueous media. HCl-treated p (APTMACl-co-AMPS) hydrogels prepared in 1:3 mol ratio adsorbed higher amount of MB and EY from their corresponding 50 ml 50 ppm aqueous solutions that are 47.5 ± 0.9, and 10.7 ± 0.1 mg/g, respectively. Also, the adsorbed amount of MB and EY by HCl-treated p (APTMACl-co-AMPS) hydrogels decreased with the increase in the medium pH from 3.0 to 9.0. It was also observed that HCl-treated p (APTMACl-co-AMPS)-3 hydrogels removed 39.2 ± 0.2, and 28.1 ± 1.0 mg/g MB and EY dyes simultaneously from their corresponding 50 ml 50 ppm aqueous mixture solutions. MB and EY adsorption by HCl-treated p (APTMACl-co-AMPS)-3 hydrogels were found to abide by pseudo-first-order adsorption kinetics. Moreover, MB adsorption by HCl-treated p (APTMACl-co-AMPS) hydrogels were found to fit with Freundlich, EY adsorption fit with Langmuir isotherms. The distribution coefficient values of HCl-treated p (APTMACl-co-AMPS) hydrogels were calculated as 3.7 ± 0.1 and 1.3 ± 0.1 for MB and EY, respectively. The calculated selectivity coefficient value showed that HCl-treated p (APTMACl-co-AMPS) hydrogels are at least 3-fold higher selective to MB than EY.

Fabrication of novel ZnTe-based photocatalyst: Synergistic effect of dye sensitization and bridge engineering for boosting hydrogen evolution over ZnTe

Herein, a novel ZnTe-based photocatalyst is successfully synthesized via a facile combination of water-bath and hydrothermal processes. Morphology characterization and X-ray diffraction analysis reveal that ZnTe presents irregular granular shape and cubic crystal structure. Moreover, Mott-Schottky measurement shows that the conduction band potential of ZnTe is −0.84 V (vs NHE). With Eosin Y (EY) sensitization, ZnTe exhibits superior photocatalytic hydrogen evolution activity (223.5 μmol g−1 h−1). Meanwhile, WC-ZnTe heterojunction is constructed by depositing ZnTe nanoparticles on bulk WC and obtains the optimal H2 generation rate (559.1 μmol g−1 h−1) under EY sensitization. Electrochemical and photoluminescence results further prove that WC as electron bridge could reduce the interfacial resistance and suppress e−-h+ pairs recombination. This study explores the potential application of ZnTe as a newly active photocatalyst in photocatalytic water splitting, and emphasizes the synergistic effect of dye sensitization and bridge engineering.

Wheat straw-core hydrogel spheres with polypyrrole nanotubes for the removal of organic dyes

Straw biomass is an underutilized raw material, the use of which could make a significant contribution to sustainable development. Herein, wheat straw waste was regenerated into novel porous core-shell wheat straw-polypyrrole hydrogel spheres for the removal of dyes from wastewater. Adsorption experiments demonstrated that the hydrogel spheres had long-term structural and functional stability, and a high performance for the removal of the water-soluble model anionic dye eosin Y (EY). The maximum adsorption capacity of the hybrid spheres (520.2 mg/g) was 12 times greater than that of the wheat straw hydrogel sphere. Recycling experiments showed that it the initial adsorption capacity of 75.0% could be maintained after seven adsorption-desorption cycles, and the material could be recovered by simple filtration. The results from spectroscopic (FTIR, XPS) analysis, adsorption experiments and computational quantum mechanical modelling suggested that hydrogen bonds, π-π stacking and electrostatic forces, were involved in the removal of EY from aqueous solution. Interestingly, the hydrogel sphere exhibited enhanced adsorption at elevated temperature, and this could be attributed to the dynamic breaking of crosslinked hydrogen bonds in the hydrogel sphere and release of activated –OH. The results from this study provide a basis for the development of sustainable high-performance adsorption materials from wheat straw biomass for the removal of organic dyes from wastewater. It also provides a strategy to design adsorbents that work efficiently at elevated temperatures.

Supramolecular Nanohelix Fabricated by Pillararene-Based Host–Guest System for Chirality Amplification, Transfer, and Circularly Polarized Luminescence in Water

Supramolecular Nanohelix Fabricated by Pillararene-Based Host–Guest System for Chirality Amplification, Transfer, and Circularly Polarized Luminescence in Water