Ultraviolet Stability Research Articles

Copper Ion-Chelated and Polydopamine-Modified Hydroxypropyl Methylcellulose Nanoparticles with Multiple Responses for Intelligent Pesticide Release and Improved Foliar Deposition.

Intelligent controlled-release nanopesticides have been a crucial tactic in advanced precision agriculture during the past few years, which can improve pesticide utilization and reduce environmental pollution. Herein, a novel hydroxypropyl methylcellulose-based nanopesticide carrier (PCH) with pH-/enzyme-/near-infrared multiple responses was constructed by the initial cross-linking with dimethyl diallyl ammonium chloride and the subsequent copper ion chelation and polydopamine coating. Avermectin (Av) was further loaded to create the intelligent pesticide release system (APCH) by antisolvent precipitation. The release of APCH increases under near-infrared light (NIR) conditions, with an accumulative release that is 3.26 times higher than that without NIR. The contact angles of APCH on cabbage leaves are 33 and 29% lower than those of water and technical Av (Av-tech), respectively, verifying that APCH has a good wettability property. Simultaneously, APCH displays better insecticidal activity than Av formulations because of its outstanding ultraviolet (UV) light stability of Av. The degradation rate of Av in APCH is less than 2% in 50 h under UV light, which is considerably lower than that of Av-tech (∼60%). The biosafety assessments manifest that the PCH carrier has remarkable biological safety on the growth of nontarget organisms in a certain range. Overall, the APCH system is bio-friendly with multiple-response release behaviors, excellent UV light stability, and foliar deposition performance, which can offer a new strategy for sustainable agricultural development.

Degradation of 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV328) in soil by FeS activated persulfate: Kinetics, mechanism, and theoretical calculations

2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV328) is a commonly used benzotriazole ultraviolet stabilizers (BUVs) with bioaccumulative properties. Since it’s stubbornly degraded in the environment, it poses significant environmental risks in soil. However, the removal of UV328 from soil is challenging, and existing treatment methods have low efficiency. This study focuses on UV328 in soil and proposes an efficient method for its removal using persulfate (PS) activated by iron sulfide (FeS). The research demonstrates that with FeS and PS dosages of 20 and 100 mM respectively, and a soil-to-water ratio of 5:1, 12 h-removal efficiency of UV328 with an initial concentration of 12 mg/kg reaches 93.0%. Furthermore, employing electron paramagnetic resonance spectroscopy and quenching experiments, key reactive oxygen species (ROSs) are identified. SO4•-, •OH, 1O2 and •O2- contribute 31.76%, 28.77%, 26.52% and 12.95%, respectively. Four main reaction pathways of amination, hydroxylation, sulfate substitution, and bond cleavage, are identified with 14 transformation products characterized. Calculated energy profiles based on density functional theory (DFT) identify the most susceptible reaction sites for different ROSs. Five different types of agricultural soils were selected to explore the impact of soil characteristics on UV328 removal. The degradation performance of natural mackinawite demonstrates the effectiveness and accessibility of raw materials. Toxicity assessments of transformation products confirm the environmental friendliness of this system. This study proposes an efficient degradation method for UV328-contaminated soil, providing scientific insights and theoretical guidance for addressing environmental removal of BUVs from soil.

Improving efficiency and ultraviolet stability of perovskite solar cells by using multifunctional octocrylene at SnO2 buried interface

Improving efficiency and ultraviolet stability of perovskite solar cells by using multifunctional octocrylene at SnO2 buried interface

Toxicokinetics of benzotriazole UV stabilizer UV-P in humans after single oral administration.

UV-P (2-(2H-Benzotriazol-2-yl)-p-cresol) is used as an ultraviolet (UV) light absorber in coating products, paints, adhesives, and sealants. Due to its widespread industrial and consumer uses, human exposure to UV-P is conceivable. In the study presented herein, initial data on its human invivo metabolism were obtained for three study participants after single oral administration of 0.3mg of UV-P/kg body weight. Urine and blood samples of two volunteers were collected up to 48h after exposure. The third study participant donated urine and blood samples up to 72h. Maximum levels of UV-P in blood of 184 ± 36µg/l (85 ± 3% as conjugates) were reached 2.4 ± 1.2h post-exposure. Maximum excretion rates of UV-P in urine of 2896 ± 884µg/h (completely conjugated) were reached 3.5 ± 1.1h post-exposure. 37.2 ± 5.4% of the orally administered dose of UV-P was recovered in urine within 48h post-exposure. The present study provides insight into the complex absorption, distribution, metabolism, and elimination (ADME) processes of benzotriazole UV stabilizers (BUVS). The study also demonstrates differences in the ADME between sterically hindered BUVS, such as UV-327 and UV-328, and sterically unhindered BUVS, such as UV-P, in which the phenolic hydroxyl group is readily accessible for conjugation with glucuronic acid or sulfate.

High-Performance Radiative Cooling Sunscreen.

Radiative cooling is a zero-energy-consumption cooling technology that shows great potential for outdoor human thermal management. To keep human skin comfortable in hot days, we herein develop a radiative cooling (RC) sunscreen that exhibits a low ultraviolet (UV) transmissivity (4.86%), a high solar reflectivity (90.19%), and a high mid-infrared emissivity (92.09%) to effectively provide both UV protection and skin cooling. As a result, the RC sunscreen exhibits a high cooling performance for decreasing the human skin temperature by 2.3-6.1 °C more than commercial sunscreens and 4.2-6.0 °C more than bare skin in a variety of outdoor scenarios in summer (e.g., low-humidity sunny days, high-humidity sunny days, and high-humidity cloudy days). In addition, the RC sunscreen also shows a good UV stability (12 h, 125 W), a high water resistance (106°), a long working life (30 days), and a good biocompatibility, thereby exhibiting promising commercial potentials in the sunscreen market.

Dynamic impact of different human activities on the distribution of organic ultraviolet absorbers in coastal aquatic environments: A case study in Beibu Gulf, South China Sea

The increasing environmental concern surrounding organic ultraviolet absorbers (OUVAs) has prompted heightened attention, particularly their presence in personal care products (organic ultraviolet filters, OUVFs) and industrial products (organic ultraviolet stabilizers, OUVSs). This study investigates the impact of human activities and environmental factors on the occurrence, spatiotemporal distribution, and ecological risk of eight commonly utilized OUVFs and OUVSs in the coastal region of Beibu Gulf, South China Sea. The study area is characterized by multiple functional zones with distinct human activities. Results reveal elevated concentrations of OUVAs during summer compared to winter, attributed to increased residential usage, tourist activities, industrial releases, and intensified ultraviolet (UV) radiation. Interestingly, the proportion of OUVFs increases during summer, while OUVSs decrease. Correlation analysis between OUVAs and sampling sites reveals that tourism and domestic wastewater are the main contributors to OUVF contamination in summer, whereas mariculture and port trade significantly impact OUVS contamination in winter. The ecological risk assessment indicates predominantly low or medium risk levels for most OUVAs in both local seawater and freshwater ecosystems. Nevertheless, OUVFs, with a particular focus on 4-methylbenzylidene camphor (4-MBC), and OUVSs, specifically 2-(2-hydroxy-5-methylphenyl) benzotriazole (UV-P), exhibit a heightened risk compared to alternative substances. These findings provide crucial insights into the development of targeted mitigation strategies for OUVAs, taking into account the varying contamination levels of OUVFs and OUVSs resulting from diverse human activities, aiming to protect the health of aquatic ecosystems in diverse functional zones.

Preparation and artificial weathering properties of Ce/TiO2/BTA-HALS coating on heat-treated wood surface

Heat-treated wood has only short-term weathering resistance, while wood cracking, discoloring and other problems will appear in long-term outdoor environments. Therefore, it is necessary to enhance the anti-weathering properties of heat-treated wood. In this study, organic ultraviolet absorbers, light stabilizers and inorganic Cerium/Titanium dioxide (Ce/TiO2) ultraviolet shielding agents were compounded by the simple physical blending method, and the modifiers were loaded on the surface of heat-treated wood by brushing method. The UV-Vis spectrum showed the high transparency and UV shielding of the composite coating. After artificial weathering, the color difference (ΔE) of Ce/TiO2/BTA-HALS coated sample was only 1.64 and 2.68, which is significantly lower than 2.3 and 6.1 of the heat-treated sample. The surface roughness, scanning electron microscope and X-ray energy spectrum also showed that the stability of the coating was significantly improved, and the loss of inorganic particles has decreased. Fourier transform infrared spectroscopy and electron paramagnetic resonance proved that the modifier was successfully grafted on the surface of heat-treated wood. The composite coating has a certain synergistic effect in improving the weathering resistance of heat-treated wood and improves the film-forming property of the modifier and the stability of the coating during weathering.

Goat lactoferrin–pterostilbene complexes as novel edible functional proteins with enhanced ultraviolet stabilization and antioxidant properties

The use of polyphenols for enhancing protein function in the food industry is limited by their low bioavailability and stability. In this study, we developed complexes of the polyphenol pterostilbene (PTE) and goat lactoferrin (GLF) with the aim of developing a nutritionally enhanced food base with improved functional properties. Specifically, we investigated the binding affinity, structure, and functional modifications of PTE encapsulated with GLF. Fluorescence spectroscopy revealed notable changes in GLF, characterized by reduced fluorescence intensity and a blue shift in the emission peak, following interaction with varying concentrations of PTE. Fourier transformer infrared spectroscopy demonstrated a decrease in β-sheet content and an increase in β-turn structure with increasing PTE level. These structural alterations were furthered confirmed through molecular docking and molecular dynamics simulations. Furthermore, GLF–PTE complexes exhibited improved surface hydrophobicity, foaming capability, and emulsifying activity properties. Importantly, GLF maintained the antioxidant capacity of PTE under UV light irradiation and improved the bioaccessibility of PTE according to in-vitro intestinal digestion simulation assays. Furthermore, the GLF–PTE complexes showed no significant cytotoxicity to mouse fibroblast-like, goat mammary epithelial, or human kidney epithelial cells. This study elucidates the interaction mechanisms between GLF and PTE and supports the potential application of GLF–PTE complexes in food systems owing to their enhanced functional properties and bioactivity.

Waste-derived carbon quantum dots for improving the photostability of perovskite solar cells to > 1,000 h

Power conversion efficiency (PCE) of perovskite solar cells (PSCs) has reached 26.1%, but PSC devices are plagued by poor stability when exposed to light (especially ultraviolet (UV) radiation), heat, and moisture. UV stability remains a significant challenge to overcome. Luminescent down-shifting (LDS) filters have shown significant enhancement in photostability and efficiency for PSCs. However, most explored LDS materials are costly, non-biodegradable, and the resulting photostability is limited to ∼100 h. In this report, as-obtained waste filtrate from the polyaniline (PANI) synthesis is used to synthesize fluorescent PANI carbon quantum dots (PANI-CQDs) using a facile hydrothermal method. Here we report, for the first time, the use of waste-derived PANI-CQDs to fabricate UV filters that are low-cost, bio-degradable, and room-temperature processible and, importantly, impart high UV and photostability to the PSCs. PSCs with these filters retained 90% and 100% of their initial performance when exposed to UV light and AM 1.5 solar radiation, respectively, for more than 900 h, while PSCs without filters degraded to 14 and 70% of their initial performance under the same conditions. Hence, we clearly show that using a waste-derived LDS filter improves the UV stability of PSCs by six times and photostability beyond 1,000 h.

Study on the construction of durable superhydrophobic coatings using simple spray coating method and their underwater drag reduction performance

Superhydrophobic surfaces have significant applications in industrial and chemical fields. However, their current mechanical stability and underwater durability are insufficient, limiting their widespread application. This study successfully developed a durable superhydrophobic coating suitable for various substrates using a simple one-step spraying technique. By thoroughly investigating the effects of SiO2 concentration and curing temperature on the coating's wettability, underwater durability and mechanical stability, the preparation process was optimized. The prepared superhydrophobic coating achieved a contact angle (CA) of 159.6° and a sliding angle (SA) of less than 1°. In tests of underwater immersion, sandpaper abrasion, repeated water impact, corrosion resistance and ultraviolet (UV) resistance, the coating demonstrated excellent underwater durability, mechanical stability, chemical stability and UV stability. Furthermore, when applied to the steel sphere, the superhydrophobic coating exhibited significant drag reduction effects underwater, reducing the drag coefficient by approximately an order of magnitude and achieving a drag reduction efficiency of 79.1 %. Numerical simulations using STAR-CCM+ showed that the streamlined cavity formed by the superhydrophobic coating effectively suppressed fluid separation, reduced pressure-induced drag, and allowed the superhydrophobic steel sphere to attain a higher terminal velocity. Therefore, the superhydrophobic coating developed in this study has tremendous application potential in underwater drag reduction and is expected to provide effective solutions for energy-saving and drag reduction in fields such as maritime navigation.

Coordinated responses of rice (Oryza sativa) to the stresses of benzotriazole ultraviolet stabilizers (BZT-UVs): Antioxidative system, photosynthetic activity, and metabolic regulation

Massive use of plastic products has caused their accumulation in soils, releasing large amounts of endogenous plastic additives (e.g., benzotriazole ultraviolet stabilizers, in short BZT-UVs) into terrestrial ecosystems. However, their plant toxicity is little known. Herein, we investigated the occurrence of BZT-UVs in contaminated farmland and selected three BZT-UV congeners to explore their toxic effects on the antioxidant, photosynthetic, and metabolic perturbation on rice (Oryza sativa). Results showed that the mean concentrations of ∑BZT-UVs in soil and plant samples were 180.7 ng/g dw and 156.4 ng/g dw, respectively. UV-P, UV-327 and UV-328 were the dominant BZT-UV congeners in both of soils and plants. Three BZT-UV congeners caused oxidative damages to rice in a dose-dependent manner, especially for UV-328. Functional genes involved in chlorophyll synthetases was inhibited by over 50 % under the stress of BZT-UVs, whereas those responsible for chlorophyll degradation were obviously promoted. The chlorophyll content was thus decreased, leading to a weakened photosynthesis system and an unbalanced carbon metabolism. The transcriptome and metabolome proved that the flux of carbohydrate metabolism and amino acid metabolism were obviously promoted in plants induced by BZT-UVs, which could inhibit the growth of rice. These findings offered insights into the coordinated responses of plants and advanced our understanding of potential ecological risks of BZT-UVs to terrestrial ecosystems.

Presence of benzotriazole ultraviolet stabilizers in human urine

Health exposure to benzotriazole ultraviolet stabilizers (BUVSs) may pose diverse toxic impacts on health. Presently, the occurrence of BUVSs in human urine remains inadequately understood. This study analyzed 13 kinds of BUVSs in human urine (n = 182) from the general Chinese adult participants. Totally, nine BUVSs were measurable in these human urine samples. Among the detected BUVSs, 2-(2H-benzotriazol-2-yl)-p-cresol (UV–P) was the most predominant BUVS in the human urine, with the mean concentration of 1.6 μg/g creatinine (<LOD–11 μg/g creatinine). 2-(2′-Hydroxy-3′,5′-di-tert-butylphenyl)-5-chloro-benzotriazole (UV-327; mean 0.42 μg/g creatinine, < LOD–9.8 μg/g creatinine) was the second predominant BUVS, followed by 2-(2H-benzotriazol-2-yl)-4-(1,1-dimethylethyl)-phenol (UV-PS; 0.21 μg/g creatinine, < LOD–8.5 μg/g creatinine) and 2-(2H-benzotriazol-2-yl)-4,6-ditertpentyl-phenol (UV-328; 0.18 μg/g creatinine, < LOD–3.4 μg/g creatinine). The mean urinary concentration of UV-327 in females (0.51 μg/g creatinine) was remarkably greater (p = 0.027) than that in males (0.26 μg/g creatinine). Human urinary concentrations of UV-P and UV-328 were decreased with the age of participants. Relative higher urinary daily excretion was found for UV-P (<1.7–316 ng/kg bw/day), UV-327 (<2.8–267 ng/kg bw/day), and UV-PS (<1.4–201 ng/kg bw/day). The current study first reveals the urinary concentrations of BUVSs in general Chinese population. These obtained data is fundamental for the risk assessment of human BUVSs ingestion.

Far from Their Origins: A Transcriptomic Investigation on How 2,4-Di-tert-butyl-6-(5-chloro-2H-benzotriazol-2-yl) Phenol Affects Rainbow Trout Alevins.

Benzotriazole ultraviolet stabilizers (BUVSs) are a group of widely used chemicals added to a variety of consumer (e.g., plastics) and industrial (e.g., metal coating) goods. Although detected globally as an environmentally persistent pollutant, BUVSs have received relatively little toxicological attention and only recently have been acknowledged to affect development and the endocrine system in vivo. In our previous study, altered behavior, indicative of potential neurotoxicity, was observed among rainbow trout alevins (day 14 posthatching) that were microinjected as embryos with a single environmentally relevant dose of 2,4-di-tert-butyl-6-(5-chloro-2H-benzotriazol-2-yl) phenol (UV-327). In the present follow-up study, we performed whole-transcriptome profiling (RNA sequencing) of newly hatched alevins from the same batch. The primary aim was to identify biomarkers related to behavior and neurology. Dose-specifically, 1 to 176 differentially expressed genes (DEGs) were identified. In the group presenting altered behavior (273.4 ng g-1), 176 DEGs were identified, yet only a fraction was related to neurological functions, including water, calcium, and potassium homeostasis; acetylcholine transmission and signaling; as well insulin and energy metabolism. The second objective was to estimate the transcriptomic point of departure (tPOD) and assess if point estimate(s) are protective of altered behavior. A tPOD was established at 35 to 94 ng UV-327 g-1 egg, making this tPOD protective of behavioral alterations. Holistically, these transcriptomic alterations provide a foundation for future research on how BUVSs can influence rainbow trout alevin development, while providing support to the hypothesis that UV-327 can influence neurogenesis and subsequent behavioral endpoints. The exact structural and functional changes caused by embryonic exposure to UV-327 remain enigmatic and will require extensive investigation before being deciphered and understood toxicologically. Environ Toxicol Chem 2024;43:2026-2038. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Synthesis and stability of Cs-rich α phase Cs1-xDMAxPbI2Br(0 ≤ x ≤ 0.3) perovskite film

In this study, we successfully synthesized α-phase Cs1-xDMAxPbI2Br(0 ≤ x ≤ 0.3) without impurity and conducted device performance research and stability testing on it. The champion photoelectric conversion efficiency of α phase Cs0.8DMA0.2PbI2Br in inverted perovskite solar cells is 8.24 %. Compared with pure CsPbI2Br without DMA+, humidity stability of α-Cs0.8DMA0.2PbI2Br has been improved and it also maintains thermal and ultraviolet stability. This strategy shows bright application prospect for improving the stability of CsPbI2Br perovskite solar cells.

Probabilistic risk assessment of dietary exposure to benzophenone derivatives in cereals in Taiwan.

Benzophenone (BP) and BP derivatives (BPDs) are widely used as ultraviolet (UV) stabilizers in food packaging materials and as photoinitiators in UV-curable inks for printing on food-contact materials. However, our knowledge regarding the sources and risks of dietary exposure to BP and BPDs in cereals remains limited, which prompted us to conduct this study. We measured the levels of BP and nine BPDs-BP-1, BP-2, BP-3, BP-8, 2-hydroxybenzophenone, 4-hydroxybenzophenone, 4-methylbenzophenone (4-MBP), methyl-2-benzoylbenzoate, and 4-benzoylbiphenyl-in three types of cereals (rice flour, oatmeal, and cornflakes; 180 samples in total). A Bayesian Markov-chain Monte Carlo (MC) simulation approach was used for deriving the posterior distributions of BP and BPD residues. This approach helped in addressing the uncertainty in probabilistic distribution for the sampled data under the detection limit. Through an MC simulation, we calculated the daily exposure levels of dietary BP and BPDs and corresponding health risks. The results revealed the ubiquitous presence of BP, BP-3, and 4-MBP in cereals. Older adults (aged>65 years) had the highest (97.5 percentile) lifetime carcinogenic risk for BP exposure through cereals (9.41 × 10-7), whereas children aged 0-3 years had the highest (97.5 percentile) hazard indices for BPD exposure through cereals (2.5 × 10-2). Nevertheless, across age groups, the lifetime carcinogenic risks of BP exposure through cereals were acceptable, and the hazard indices for BPD exposure through cereals were<1. Therefore, BPD exposure through cereals may not be a health concern for individuals in Taiwan.

The construction of Moringa oleifera seed protein emulsion: in vitro digestibility and delivery of β-carotene.

β-Carotene (BC) is difficult to apply effectively in the food industry due to its low solubility and bioavailability. This work aimed to fabricate Moringa oleifera seed protein (MOSP) stabilized emulsions as delivery vehicles for BC and investigate the effect of aqueous phase conditions including pH and ionic strength on this system. All MOSP samples were positively charged and the particle size of MOSP increased with the increase of pH. At pH 5.0 and 0.2 mol L-1 sodium chloride (NaCl), the MOSP emulsion demonstrated the highest stability coefficient and minimal creaming index, while exhibiting a lower release rate in vitro digestion. The rheological behavior of all MOSP emulsions within the frequency range of 0.1-10 Hz was dominated by viscoelasticity, forming an elastic network structure through dispersed droplets. Additionally, the MOSP emulsion loaded with BC prepared at pH 5.0 and 0.2 mol L-1 NaCl displayed enhanced ultraviolet light stability (52.31 ± 0.03% and 51.86 ± 0.05%) as well as thermal stability (72.39 ± 8.67% and 86.78 ± 10.69%). Furthermore, the BC in the emulsion at pH 7.0 exhibited favorable stability (65.14 ± 0.02%) and optimal bioaccessibility (40.30 ± 0.04%) in vitro digestion. The results provided reference data for utilizing MOSP as a novel emulsifier and broadening the application of BC in the food industry. © 2024 Society of Chemical Industry.

Strong-bonding hole-transport layers reduce ultraviolet degradation of perovskite solar cells

The light-emitting diodes (LEDs) used in indoor testing of perovskite solar cells do not expose them to the levels of ultraviolet (UV) radiation that they would receive in actual outdoor use. We report degradation mechanisms of p-i-n–structured perovskite solar cells under unfiltered sunlight and with LEDs. Weak chemical bonding between perovskites and polymer hole-transporting materials (HTMs) and transparent conducting oxides (TCOs) dominate the accelerated A-site cation migration, rather than direct degradation of HTMs. An aromatic phosphonic acid, [2-(9-ethyl-9H-carbazol-3-yl)ethyl]phosphonic acid (EtCz3EPA), enhanced bonding at the perovskite/HTM/TCO region with a phosphonic acid group bonded to TCOs and a nitrogen group interacting with lead in perovskites. A hybrid HTM of EtCz3EPA with strong hole-extraction polymers retained high efficiency and improved the UV stability of perovskite devices, and a champion perovskite minimodule—independently measured by the Perovskite PV Accelerator for Commercializing Technologies (PACT) center—retained operational efficiency of &gt;16% after 29 weeks of outdoor testing.

Gauge Field Marginal of an Abelian Higgs Model

We study the gauge field marginal of an Abelian Higgs model with Villain action defined on a 2D lattice in finite volume. Our first main result, which holds for gauge theories on arbitrary finite graphs and does not assume that the structure group is Abelian, is a loop expansion of the Radon–Nikodym derivative of the law of the gauge field marginal with respect to that of the pure gauge theory. This expansion is similar to the one of Seiler (Gauge theories as a problem of constructive quantum field theory and statistical mechanics, volume 159 of lecture notes in physics, Springer, Berlin, p v+192. https://doi.org/10.1007/3-540-11559-5, 1982) but holds in greater generality and uses a different graph theoretic approach. Furthermore, we show ultraviolet stability for the gauge field marginal of the model in a fixed gauge. More specifically, we show that moments of the Hölder–Besov-type norms introduced in Chevyrev (Commun Math Phys 372(3):1027–1058. https://doi.org/10.1007/s00220-019-03567-5, 2019) are bounded uniformly in the lattice spacing. This latter result relies on a quantitative diamagnetic inequality that in turn follows from the loop expansion and elementary properties of Gaussian random variables.

Improved UV stability of perovskite devices based on the synergistic effect of electron layer passivation engineering and component engineering

The electron transport layer is one of the key factors in constructing high-performance perovskite solar cells (PSCs). Pb2+ reduction induced by ultraviolet light can cause the generation of vacancies and defects, leading to the degradation of perovskite films and the reduction of PSCs performances. Ethylenediamine tetraacetic acid disodium salt (EDTA) is a chelating agent that can bind to Sn2+ divalent metal ions and hence change material properties. Herein, EDTA-SnO2/CeO2 composite electron transport layers were constructed to improve the ultraviolet light stability of PSCs. The oxygen defect in electron layers of tin dioxide could be passivated by the surface of EDTA; whilst rod-like CeO2 was used as a mesoporous electron transport layer and UV shielding agent, which can reflect UV light and prevent the absorption layer from being damaged. CeO2 has also a suitable band gap; this accelerates the charge extraction and transfer, suppresses the recombination of interfacial carriers. The experimental results showed that the ultraviolet light stability of PSCs was significantly improved. After continuous irradiation of ultraviolet light with energy of 80 mW/cm2 for 12 h, the unencapsulated device with CeO2 maintained nearly 90% the initial efficiency.

Discovery of novel benzotriazole ultraviolet stabilizers in surface water

The comprehensive understanding of the occurrence of benzotriazole UV stabilizers (BZT-UVs) in environmental surface water is imperative due to their widespread application and potential aquatic toxicity. We conducted an analysis of 13 traditional BZT-UVs in surface water samples collected from Taihu Lake (TL, n = 23) and Qiantang River (QR, n = 22) in China. The results revealed that 5‑chloro-2-(3,5-di-tertbutyl-2-hydroxyphenyl)-benzotriazole (UV-327) was consistently the predominant BZT-UV in water samples from TL (mean 16 ng/L; detection frequency 96 %) and QR (14 ng/L; 91 %). Furthermore, we developed a characteristic fragment ion-based strategy to screen and identify unknown BZT-UVs in collected surface water, utilizing a high-resolution mass spectrometer. A total of seven novel BZT-UVs were discovered in water samples, and their chemical structures were proposed. Four of these novel BZT-UVs were further confirmed with standards provided by industrial manufacturers. Semi-quantitative analysis revealed that among discovered novel BZT-UVs, 2-(2‑hydroxy-3‑tert‑butyl‑5-methylphenyl)-benzotriazole was consistently the predominant novel BZT-UV in TL (mean 4.1 ng/L, detection frequency 70 %) and QR (2.8 ng/L, 77 %) water. In TL water, the second predominant novel BZT-UV was 2-(3-allyl-2‑hydroxy-5-methylphenyl)-2H-benzotriazole (mean 3.9 ng/L, <LOD–11 ng/L), while in QR water, it was 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4‑hydroxy-benzotriazole (mean 2.1 ng/L, <LOD–3.6 ng/L). Subsequent studies are needed to elucidate the environmental source, behaviors, and aquatic toxicity of these newly identified BZT-UVs in surface water.