Search

Three new chromophores based on difluoroborondipyrromethene dyes (Bodipy‐1, Bodipy‐2, and Bodipy‐3) are used as precursors to prepare luminescent solar concentrators (LSC) based on poly‐acrylate, following a thermally activated polymerization involving lauryl methacrylate as monomer, ethyl glycol dimethacrylate as cross‐linking agent, and lauroyl peroxide as initiator. The new dyes exhibit typical BODIPY absorption and emission properties in dichloromethane fluid solution, assigned to the lower‐lying singlet π–π∗ level, which in the case of Bodipy‐2 and Bodipy‐3, both containing diamino‐substituted styryl subunits in their structure, has a strong charge transfer contribution. The LSCs obtained starting from each of the three Bodipys are interfaced to silicon photovoltaic (PV) cells, and the PV light‐to‐energy conversion efficiencies ηopt for the three systems are calculated. The results yield ηopt of 4.53% for LSC‐Bodipy‐1, 5.26% for LSC‐Bodipy‐2, and 8.23% for LSC‐Bodipy‐3. The optical efficiency for LSC‐Bodipy‐3 is a remarkable value among the LSC based on organic dyes. [ABSTRACT FROM AUTHOR]

Developing economical and high‐performing sensitizers is crucial in advancing dye‐sensitized solar cells (DSSCs) and optoelectronics. This research paper explores the potential of novel red light‐absorbing organic dyes based on Indolo[3,2‐b]carbazole (ICZ) as the donor applied in co‐sensitizer‐free DSSCs for breakthroughs in photovoltaic (PV) applications. DFT and TD‐DFT based computational methods were employed to calculate the conduction band levels, electron injection capabilities, and power conversion efficiency (PCE) of metal‐free organic dyes (ICZ1–ICZ9) having D‐A‐π‐A architecture. Comprehensive analyses included NBO, DOS, FMO, ICT, MEP, binding energy, and TDM analysis. Quantum chemical calculations of the structural, photochemical, and electrochemical properties, as well as the key parameters, reveals that all the designed dyes could be an excellent candidate for high‐efficiency DSSCs due the small energy gap (2.130–1.947 eV), longer wavelength absorption (759.47–520.63 nm), longer lifetimes (15.65–6.67 ns), a lower ΔGreg (0.29–0.14 eV), a significant dipole moment changes (31.489–16.195D), LHE (0.95‐0.46), the large qCT (0.962–0.689), small DCT (7.657, 4.897 Å), and VOC (1.13–0.86 eV). This quantum simulation showed that, when compared to reference D8, the photovoltaic dyes ICZ8, ICZ2, and ICZ7 are recognized as being eye‐catching. Furthermore, dye@(TiO2)9 cluster model results demonstrate promising prospects for enhancing the photovoltaic (PV) performance of ICZ1–ICZ9 dyes by electron injection and conduction band (CB) engineering. This study will help the experimentalists for developing ICZ‐based PVs as more efficient and sustainable energy solutions. [ABSTRACT FROM AUTHOR]

In this study, photocatalysts with high photocatalytic activity performance are synthesized by synthesizing graphene aerogel‐supported, cadmium‐doped TiO2 composites by hydrothermal method for the effective degradation of organic dyes in wastewater. Here, GA–TiO2–Cd is investigated as a photocatalyst for the degradation of toxic dyes named Orange G, Acid Blue 161, and Brilliant Green in the UV part of the light spectrum. As a result of the experiments, it is observed that the effective decomposition of organic dyes is due to graphene aerogel (GA) and cadmium‐doped TiO2 nanoparticles. The results show that for 20 ppm solutions of Orange G, Acid Blue 161, and Brilliant Green, dyes are removed at approximately 81.075%, 84.15%, and 95.18% in 120 min. The morphology and elemental analysis of the synthesized composites are determined using SEM‐EDS, crystal structure analysis by XRD, chemical bond analysis by FTIR, optical properties by UV‐Vis‐NIR spectrophotometry, and thermal resistance by TGA analysis. [ABSTRACT FROM AUTHOR]

Tribocatalysis is one of the emerging processes for organic dye degradation application. The process uses mechanical energy as a source for breaking down organic pollutants present in water. The synergistic effect of two catalysis processes for eliminating organic pollutants, here in the present study photocatalysis an advanced oxidation process is integrated with the tribocatalysis process for enhancing the degradation efficiency of the tribocatalysis process by using BaTiO3 ceramic powder as a catalyst. The responsible factors for dye degradation via the tribocatalysis process such as surface roughness of the materials utilized, force applied, and energy band gap of the catalyst are also studied. The Methylene Blue dye's degradation was ~39%, ~60%, and ~76% through tribocatalysis, photocatalysis, and photo-tribocatalysis respectively by using 400 mg BaTiO3 ceramic powder in 8 h. The synergistic effect of photocatalysis and tribocatalysis process showed enhanced degradation compared to individual processes. [ABSTRACT FROM AUTHOR]

Advanced oxidation processes based on sulfate radical are considered one of the most promising wastewater treatment technologies currently. Among heterogeneous catalysts, cobalt metal–organic framework (MOF) has been widely reported. However, the inherent powder form of MOF hinders its practical application and reusability. Therefore, innovative methods to increase the loading capacity and the accessibility of MOF active sites in monolithic materials are required. Therefore, a simple and scalable method of fabricating a stable, hierarchical porous zeolitic imidazolate framework (ZIF‐67) 3D sponge by growing MOF on a short electrospun fiber network is shown. The sponge can efficiently activate peroxymonosulfate and rapidly degrade an exemplary organic dye (Rhodamine B) with a degradation efficiency of 100%. The resulting multilevel, hierarchical porous structure is beneficial to the mass transfer of reagents making the catalytic process efficient. This also enables the use of the ZIF‐67 as an efficient catalytic filter for continuous removal of dye. The sponge can be recycled and reused for several cycles due to its robustness without loss in efficiency. The proposed research strategy provides a new way to design MOF 3D monolithic materials. [ABSTRACT FROM AUTHOR]

The transient electron donor–acceptor (EDA) complex has been an emerging area in the photoinduced organic synthesis field, generating radicals without exogenous transition‐metal or organic dye‐based photoredox catalysts. The catalytic platform to form suitable photoactive EDA complexes for photochemical reduction reactions remains underdeveloped. Herein, a general photoinduced reductive alkylation via the EDA complex strategy is described. A simple yet multifunctional system, triphenylphosphine and iodide salt, promotes the photoinduced decarboxylative hydroalkylation, and reductive defluorinative decarboxylative alkylation of trifluoromethyl alkenes, to access trifluoromethyl alkanes and gem‐difluoroalkenes. Moreover, decarboxylative hydroalkylation can be applied to more kinds of electron‐deficient alkenes as a general Giese addition reaction. [ABSTRACT FROM AUTHOR]

Piezoelectric materials can convert mechanical energy into electrical energy, and further piezocatalysis can be designed based on the product between piezoelectric effect and electrochemical redox effect, which is hopeful for the actual dye decomposition. Tourmaline is a natural mineral with spontaneous polarization, which is an ideal piezocatalytic material and is rarely reported in dye decomposition. In this work, after 100 mg tourmaline powder is vibrated for 120 min, the piezocatalytic dye decomposition ratios of rhodamine B (RhB), methylene blue, and methyl orange are ∼95%, ∼46%, and ∼23%, respectively. The corresponding first‐order reaction kinetic values for these three dyes are 0.02681, 0.00639, and 0.00246 min−1, respectively. By adjusting the pH value of the initial RhB solution to 5, the decomposition ratio can reach ∼99% after only 60 min of vibration. In the process of dye decomposition, it is determined that the main active substances are hydroxyl radicals and superoxide radicals via electron spin–resonance spectra test. The spontaneous polarization performance of tourmaline can effectively adsorb dye molecules to promote the catalytic reaction. Natural tourmaline minerals are abundant, low cost, and environmentally friendly making them suitable for large‐scale piezocatalysis of mineral materials. [ABSTRACT FROM AUTHOR]

The Bell Test (ASTM‐D1693) is commonly used to accelerate part failure in order to evaluate resin selection for applications like piping and tanks where environmental stress cracking is possible, even though the method tends to offer less than desirable repeatability. The working hypothesis for this new study with polyethylenes was that the variability seen in failure times may be attributed to a higher sensitivity of the phase morphology primarily at or near the surfaces of a notch than more commonly referenced bulk descriptors of a polymer, affecting stresses and the localized absorption of the preferred stress cracking agent. Using an organic dye tracer to monitor penetration of stress cracking agent into the polymer along with image analysis for the notch dimensions and a load cell, the local aspects of the mechanism were evaluated for up to four grades of polyethylene of varying crystallinity. By this detailed analysis, it was revealed that for failure to occur by ESC, influences in the polymer by absorption of the stress cracking agent preceded the changes in stresses in the specimen, contrary to original expectation. There was an imminent rate increase in both stresses and notch expansion once absorption of the surfactant reached a critical concentration. This critical nature was shown to be dependent on the crystallinity of the polymer under observation, considering the size/arrangement of crystals present and entanglements formed through the amorphous contents to dictate the rate by which IGEPAL can be absorbed into a polyethylene specimen. The results of this study validate the need for greater focus on polymer properties at the notch rather than the bulk of the specimen, though more techniques for providing analysis of these properties at the notch surfaces are needed for future improvements to the mechanism. Highlights: Bromocresol dye acts as a novel visualization aid in tracking IGEPAL CO‐630 sorptionCrystallinity was related to a plasticization threshold for absorption of IGEPALAccelerated increase in internal stresses follow absorption.Variability of the Bell Test was related to crystalline properties at the notch [ABSTRACT FROM AUTHOR]

Photonic crystals (PhCs) are interesting structures for photocatalytic applications because of their capability of harnessing distinct forms of light–matter interactions within the PhCs. Of all these, overlapping one of the photonic stopband's (PSB) edge with the absorption of the PhC material or adsorbed molecules improves their excitation and generated charge carriers can subsequently induce photocatalytic reactions. The PSB position of anodic aluminum oxide PhCs (AAO‐PhCs) can be easily adjusted by modifying the anodization profile. Herein, AAO‐PhCs are designed to match the band gap of a model semiconductor enabling a general photocatalytic activity enhancement independent of the chemical to be decomposed. Fe2O3, as an example photocatalyst, is coated onto AAO‐PhCs to demonstrate efficient photocatalytic systems by utilizing the slow photon effect. Tailored Fe2O3‐AAO‐PhCs with their PSB edge at 564 nm matching the Fe2O3 band gap exhibit generally enhanced degradation of three different organic dyes while a significant activity decrease is observed when the PSB edge does not overlap with the Fe2O3 absorption. Furthermore, photocatalyst degradation can be reduced down to only 4% activity loss over six consecutive measurements by an ultra‐thin alumina coating. [ABSTRACT FROM AUTHOR]

Dye‐sensitized solar cells (DSSCs) are a feasible alternative to traditional silicon‐based solar cells because of their low cost, eco‐friendliness, flexibility, and acceptable device efficiency. In recent years, solid‐state DSSCs (ss‐DSSCs) have garnered much interest as they can overcome the leakage and evaporation issues of liquid electrolyte systems. However, the poor morphology of solid electrolytes and their interface with photoanodes can minimize the device performance. The photosensitizer/dye is a critical component of ss‐DSSCs and plays a vital role in the device's overall performance. In this review, we summarize recent developments and performance of photosensitizers, including mono‐ and co‐sensitization of ruthenium, porphyrin, and metal‐free organic dyes under 1 sun and ambient/artificial light conditions. We also discuss the various requirements that efficient photosensitizers should satisfy and provide an overview of their historical development over the years. [ABSTRACT FROM AUTHOR]

Herein, the synthesis and optoelectronic properties of a novel push–pull organic dye, pRK1, specifically designed for use in dye‐sensitized photocathodes for hydrogen generation, are reported. The chemical structure of this dye, which incorporates a benzothiadiazole moiety, is inspired by RK1, a dye previously reported as a photosensitizer in n‐type dye‐sensitized solar cells (DSSCs) with power conversion efficiencies above 10% and high stability. The photoelectrochemical activity for hydrogen evolution of pRK1 after grafting onto NiO photocathodes in combination with a cobalt tetrapyridyl catalyst [Co(bapbpy)(OH2)2](BF4)2 in aqueous solution is evaluated and compared with two reference dyes from the literature, RuP2‐bpy and P1. It is shown that among the three photocathodes studied in this work, NiO|pRK1 is the most efficient, producing up to 1.9 μmol cm−2 of hydrogen with a faradaic efficiency of 66%, under visible light irradiation in aqueous electrolyte at pH 4.5. pRK1 shows a turnover number (TONdye) of up to 145 during the 6 h chronoamperometric test, almost twice that of P1. This study demonstrates that the chemical structure of high performance dyes commonly used in DSSCs can be successfully modified to meet the requirements for light‐driven water splitting in dye‐sensitized photoelectrochemical cells. [ABSTRACT FROM AUTHOR]

The photocatalytic, sonocatalytic, and sono‐photocatalytic performances of Ba0.5Sr0.5TiO3 (BST) ceramic (synthesized through solid‐state reaction route) were investigated for the degradation of an organic dye named methylene blue (MB). The as‐prepared BST ceramic powder was characterized using a scanning electron microscope, X‐ray diffraction, X‐ray photoelectron, and Raman spectroscopy techniques. The optical energy band gap of BST ceramic was found to be ∼3.17 eV. BST has shown significant catalytic activity following sonocatalysis and photocatalysis processes, i.e, ∼48% and ∼65% in 3 h, respectively. The synergic effect of the sonocatalysis and photocatalysis processes had shown an excellent degradation of 81% in 3 h. To determine the reactive species responsible for the degradation of MB dye, a scavenger test was also performed using isopropyl alcohol (IPA), ethylenediaminetetraacetic acid (EDTA), and benzoquinone (BQ) scavengers. The degree of MB dye degradation was quantified by a phytotoxicity test on "Vigna radiata" seeds. Furthermore, the potentiality of BST ceramic was explored for water cleaning applications while irradiating it to solar radiation in real‐time conditions. [ABSTRACT FROM AUTHOR]

A new 3D printable resin formulation is developed and optimized from commercially available thiol (pentaerythritol tetrakis(3‐mercaptopropionate); PETMP) and alkyne (3‐butyn‐1‐ol; BA) monomers. Printed objects are characterized by Fourier‐transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The extraction efficiency of the printed thiol‐yne device is then investigated using a model dye – malachite green (MG). The results displayed excellent dye removal efficiency with > 95% MG removed within 5 min. The 3D‐printed devices are reusable and show 100% removal over six cycles after washing with deionized water and methanol. The presence of surface hydroxyl groups derived from the BA monomer is shown to enhance dye adsorption in comparison to control materials. The printing procedure and resin formulation are robust and consistent when devices from different resin batches are compared for MG dye removal. The thiol‐yne 3D printed devices demonstrated excellent dye removal (> 99%) from water samples collected from a tap and a nearby river source. The successful development of this resin provides a new thiol‐yne‐based resin system for stereolithography (SLA) 3D printing for the removal of organic dyes from wastewater and presents a potential for broad applications in water treatment. [ABSTRACT FROM AUTHOR]

The photocatalyst composition affects the chemical–physical properties and directly impacts photocatalytic activity, both in the hydrogen production and degradation of organic contaminants. In this work, the influence of zeolitic structures NaA, NaY, and ZSM‐5 combined with a 10% active phase, TiO2 catalyst doped with 1% copper, and cobalt cocatalysts was tested to mineralize the reactive blue dye (CI250) and to produce hydrogen by photocatalysis under ultraviolet radiation. The band gap energy was affected mainly by the cocatalyst, while the Brunauer‐Emmett‐Teller method (BET) area was affected by the zeolite structure as well as the X‐ray diffraction (XRD). The most active catalyst was the Cu@TiO2/NaY, which promoted a hydrogen production rate of 240 μmolH2gcat−1 using 10% ethanol (v/v) aqueous solution as a sacrificial agent and mineralization of 53% of the organic dye, followed by the catalysts impregnated on ZSM‐5 zeolites, which had discolouration up to 50% and hydrogen evolution of 92.6 and 109.7 μmolH2gcat−1 for the catalyst doped with Cu and Co, respectively. [ABSTRACT FROM AUTHOR]

NaNbO3 nanoparticles were obtained using the microwave‐assisted hydrothermal method followed by heat treatment. It has been shown that heat treatment to increase the crystallinity of the material and modifies particle shape, from nanowires to nanograins. Nanowires with a diameter of approximately 35 nm and a length of tens of micrometers were obtained in the shortest time ever reported in the literature. Particles in the shape of nanograins with a diameter of approximately 35 nm were obtained by burning the nanowires. The photocatalytic activity of the nanoparticles was investigated through the photodegradation of Rhodamine B dye. Electronic structure analysis using density functional theory (DFT) along with experimental techniques was performed to help understand the photocatalytic activity of each sample. The obtained nanoparticles were highly favorable for photocatalytic applications, especially the nanograins, which degraded 100% of the dye in 50 min. [ABSTRACT FROM AUTHOR]

Quartz crystals are found in nature. It is believed that these crystals are eco‐friendly and known for healing, decoration, and gem therapy. However, there is no scientific evidence of such effects, except it is a piezoelectric material. The piezocatalytic effect is viewed as having significant potential for tackling environmental challenges such as water cleaning. The piezocatalytic performance of Quartz crystals was examined and reported for a few dyes degradation. The purity of these crystals was confirmed via X‐ray diffraction, Raman spectroscopy, and X‐ray photoelectron spectroscopy analysis before experimentation. Degradation of organic dyes methylene blue, methylene violet, and Rhodamine b (RB) dyes from aqueous solutions was observed using these crystals. Naturally occurred Quartz was exposed to ultrasonic vibrations for dyes and its piezocatalytic property was studied. Furthermore, using the germination index of Cicer arientium the treated water was utilized as a growth parameter. The signature of dye degradation indicates their eco‐friendly behavior. It can be assumed that these crystals can actively participate to clean organic pollutants under the application of mechanical vibrations. [ABSTRACT FROM AUTHOR]

UV light‐induced fluorescence is widely used as a key to reveal residual shell colour patterns of Neogene and Palaeogene molluscs. However, only few examples of fluorescent colour patterns are known from Mesozoic marine shells and little is known about the nature of fluorescence in fossils. Here, UV light‐induced fluorescence reveals previously unseen abundance and diversity in the colour patterns of the basal pectinid Pleuronectites laevigatus from the Middle Triassic Muschelkalk of Central Europe. In addition to known variations of radial bands, a multitude of zigzag and zigzag‐related patterns was found. The diversity of colour patterns is comparable to modern pectinids and is interpreted as colour pattern polymorphism. Raman spectra of the colour patterns indicated the preservation of residual organic pigments with aromatic moieties. The fluorescence properties of P. laevigatus and other basal pectinids from the Muschelkalk of Germany and France are described in detail, suggesting that colour pattern fluorescence is due to colourless diagenetic products of the pigments, not to the fossil pigments themselves. A remarkable feature of the colour patterns of P. laevigatus is the presence of different fluorescence colours. Because a gradual shift of the fluorescence colour from yellow to red with decreasing intensity to finally non‐fluorescent is observed, which correlates with the provenance of the specimens, the fluorescence properties are interpreted to reflect differences in diagenetic history. The results show that the fluorescence colour of fossil molluscs, especially of Mesozoic molluscs, may be affected by diagenesis and should only be used with caution for taxonomic purposes. [ABSTRACT FROM AUTHOR]

The present work describes the effect of structural modification of carbazole‐based photosensitizers carrying carboxylic acid as a common anchoring functionality, on the photovoltaic parameters of newly fabricated DSSCs. In this study, we have selected our previously reported three carbazole‐based derivatives, viz. S1‐3 having different structural designs, that is, D‐π‐A (S1), D‐D‐π‐A (S2), and A‐π‐D‐π‐A (S3) with different donor units and π‐spacers, but an identical cyanoacetic acid anchoring unit. We have evaluated their optical, electrochemical, and photovoltaic behaviors in order to explore their structure‐property relationships. Also, the theoretical investigations were performed to obtain a deeper understanding of their HOMO‐LUMO levels, charge distribution in FMOs, directional flow of electrons within the push‐pull type sensitizers, and optical behavior. Finally, the DSSCs were constructed by employing these dyes as sensitizers without any co‐absorbents and the performance of the devices was evaluated by using illuminated current‐voltage characteristics. Among the tested dyes, di‐anchoring S3 exhibited improved PCE of 3.77 % due to its strong adsorption on the TiO2 surface that resulted in superior VOC of the cell. While the S2 containing electron‐releasing anisole as an auxiliary donor exhibited better JSC value leading to the optimum PCE of 3.73 % which is comparable to that of S3. Obviously, these results validate the role of the π‐spacer and additional donor of the sensitizers on the overall performance of the DSSCs. [ABSTRACT FROM AUTHOR]

Cold‐chain management is of high importance in preserving perishable products and in retaining quality. A visible marker on packages indicating complete maintenance of the cold chain assures safe consumption of products by end‐users and assists in reducing waste. Time‐temperature indicators (TTIs) are integrated markers that provide information about exposure of packages to adverse temperature and have been gaining increased attention by consumers. Here we present a methylene‐blue‐based derivative, N,N,N′,N′‐tetramethyl‐N10‐Boc‐phenothiazine‐3,7‐diamine (BocPTDA), that can be used as a solid‐state organic TTI dye, exhibiting an irreversible change from colorless to blue green upon heating. The conversion properties, studied using a silicagel‐coated plate, confirmed that BocPTDA undergoes a color change above 20 °C. At temperatures of 4 °C and below, no visible changes are exhibited, making BocPTDA a well‐suited marker for monitoring abrupt temperature deviations indicating improper cold‐chain management. Thus, application of BocPTDA‐based TTI systems on packages could inform consumers about the cold‐chain maintenance, assuring quality and safe consumption. [ABSTRACT FROM AUTHOR]

Since organic dyes are poorly biodegradable and completely soluble, they are difficult to be efficiently and rapidly removed. Therefore, a poly(itaconic acid)/magnetite sepiolite composite (PIA/MSEP) is prepared via a simple and environmentally friendly approach. The resulting adsorbent is employed for adsorption of methylene blue (MB) and methyl violet (MV). Factors influencing dyes adsorption efficiency are systemically researched, such as pH, contact time, temperature, and initial concentration of dye. Under optimal experimental conditions, the adsorption behaviour is satisfactorily modelled by the Langmuir model, and the maximum adsorption capacity reaches 196.08 and 175.44 mg · g−1 for MB and MV, respectively. Adsorption is a fast process, well represented by pseudo‐second‐order rate expression, and being the equilibrium reached as short as 30 minutes for both MB and MV. The thermodynamic parameters suggest a favourable, spontaneous, and endothermic process. Fast, kinetic, and convenient magnetic separation, and a high adsorption capacity, make PIA/MSEP composite an impressive adsorbent for adsorption of organic dyes. [ABSTRACT FROM AUTHOR]