Highly efficient upconversion luminescence in narrow-bandgap Y2Mo4O15.

Lanthanide-doped upconversion (UC) materials have been extensively investigated for their unique capability to convert low-energy excitation into high-energy emission. Contrary to previous reports suggesting that efficient UC luminescence (UCL) is exclusively observed in materials with a wide bandgap, we have discovered in this study that Y2Mo4O15:Yb3+/Tm3+ microcrystals, a narrowband material, exhibit highly efficient UC emission. Remarkably, these microcrystals do not display any four- or five-photon UC emission bands. This particular optical phenomenon is independent of the variation in doping ion concentration, temperature, phonon energy, and excitation power density. Combining theoretical calculations and experimental results, we attribute the vanishing emission bands to the strong interaction between the bandgap of the Y2Mo4O15 host matrix (3.37 eV) and the high-energy levels (1I6 and 1D2) of Tm3+ ions. This interaction can effectively catalyze the UC emission process of Tm3+ ions, which leads to Y2Mo4O15:Yb3+/Tm3+ microcrystals possessing very strong UCL intensity. The brightness of these microcrystals outshines commercial UC NaYF4:Yb3+,Er3+ green phosphors by a factor of 10 and is 1.4 times greater than that of UC NaYF4:Yb3+,Tm3+ blue phosphors. Ultimately, Y2Mo4O15:Yb3+/Tm3+ microcrystals, with their distinctive optical characteristics, are being tailored for sophisticated anti-counterfeiting and information encryption applications.

Electron Structure Tuned Oxygen Vacancy-Rich AuPd/CeO2 for Enhancing 5-Hydroxymethylfurfural Oxidation.

The design of high activity catalyst for the efficiently conversion of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) gains great interest. The rationally tailoring of electronic structure directly affects the interaction between catalysts and organic substrates, especially molecular oxygen as the oxidant. This work, the bimetallic catalysts AuPd/CeO2 were prepared by the combining method of chemical reduction and photo-deposition, effectively concerting charge between Au and Pd and forming the electron-rich state of Au. The increasing of oxygen vacancy concentration of CeO2 by acidic treatment can facilitate the adsorption of HMF for catalysts and enhance the yield of FDCA (99.0 %). Moreover, a series of experiment results combining with density functional theory calculation illustrated that the oxidation performance of catalyst in HMF conversion was strongly related to the electronic state of interfacial Au-Pd-CeO2. Furthermore, the electron-rich state sites strengthen the adsorption and activation of molecular oxygen, greatly promoting the elimination of ß-hydride for the selective oxidation of 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) to FDCA, accompanied with an outgoing FDCA formation rate of 13.21 mmol ⋅ g-1 ⋅ min-1 at 80 °C. The perception exhibited in this research could be benefit to understanding the effects of electronic state for interfacial sites and designing excellent catalysts for the oxidation of HMF.

Constructing a Titanium Silicon Molecular Sieve-Based Z-Scheme Heterojunction with Enhanced Photocatalytic Activity.

Titanium silicon molecular sieve (TS-1) is an oxidation catalyst that possesses a long lifetime of charge transfer excited state, high Ti utilization efficiency, large specific surface area, and good adsorption property; therefore, TS-1 acts as a Ti-based photocatalyst candidate. In this work, TS-1 coupled Bi2MoO6 (TS-1/BMO) photocatalysts were fabricated via a facile hydrothermal route. Interestingly, the optimized TS-1/BMO-1.0 catalyst exhibited a decent photodegradation property toward tetracycline hydrochloride (85.49% in 120 min) under the irradiation of full spectrum light, which were 4.38 and 1.76 times compared to TS-1 and BMO, respectively. The enhanced photodegradation property of the TS-1/BMO-1.0 catalyst could be attributed to the reinforced light-harvesting capacity of the photocatalyst, high charge mobility, and suitable band structure for tetracycline hydrochloride degradation. In addition, the mechanism of photocatalytic degradation of tetracycline hydrochloride by the TS-1/BMO-1.0 catalyst was reasonably proposed based on the band structure, trapping, and ESR tests. This research provided feasible ideas for the design and construction of high-efficiency photocatalysts for contaminant degradation.

Catalytic oxidation of toluene by manganese oxides: Effect of K+ doping on oxygen vacancy.

Alkali metal potassium was beneficial to the electronic regulation and structural stability of transition metal oxides. Herein, K ions were introduced into manganese oxides by different methods to improve the degradation efficiency of toluene. The results of activity experiments indicated that KMnO4-HT (HT: Hydrothermal method) exhibited outstanding low-temperature catalytic activity, and 90% conversion of toluene can be achieved at 243°C, which was 41°C and 43°C lower than that of KNO3-HT and Mn-HT, respectively. The largest specific surface area was observed on KMnO4-HT, facilitating the adsorption of toluene. The formation of cryptomelane structure over KMnO4-HT could contribute to higher content of Mn3+ and lattice oxygen (Olatt), excellent low-temperature reducibility, and high oxygen mobility, which could increase the catalytic performance. Furthermore, two distinct degradation pathways were inferred. Pathway Ⅰ (KMnO4-HT): toluene → benzyl → benzoic acid → carbonate → CO2 and H2O; Pathway ⅠⅠ (Mn-HT): toluene → benzyl alcohol → benzoic acid → phenol → maleic anhydride → CO2 and H2O. Fewer intermediates were detected on KMnO4-HT, indicating its stronger oxidation capacity of toluene, which was originated from the doping of K+ and the interaction between KOMn. More intermediates were observed on Mn-HT, which can be attributed to the weaker oxidation ability of pure Mn. The results indicated that the doping of K+ can improve the catalytic oxidation capacity of toluene, resulting in promoted degradation of intermediates during the oxidation of toluene.

Metal-Organic Frameworks Marry Sponge: New Opportunities for Advanced Water Treatment.

Metal-organic frameworks (MOFs) have garnered attention across various fields due to their noteworthy features like high specific surface area, substantial porosity, and adjustable performance. In the realm of water treatment, MOFs exhibit great potential for eliminating pollutants such as organics, heavy metals, and oils. Nonetheless, the inherent powder characteristics of MOFs pose challenges in terms of recycling, pipeline blockage, and even secondary pollution in practical applications. Addressing these issues, the incorporation of MOFs into sponges proves to be an effective solution. Strategies like one-pot synthesis, in situ growth, and impregnation are commonly employed for loading MOFs onto sponges. This review comprehensively explores the synthesis strategies of MOFs and sponges, along with their applications in water treatment, aiming to contribute to the ongoing advancement of MOF materials.

Surface Modification with CuFeS2 Nanocrystals to Improve the Efficiency and Stability of Perovskite Solar Cells.

Poor stability retards the industrialization of perovskite solar cells (PSCs). One of the effective ways to solve this issue is to modify the perovskite surface to improve the efficiency and stability of the PSCs. Herein, we synthesized CuFeS2 nanocrystals and applied them to modify the perovskite surface. The efficiency of the PSCs with CuFeS2 modification is improved to 20.17% from 18.64% for the control devices. Some investigations demonstrate that the CuFeS2 modification passivates the perovskite surface defects and induces better energy band arrangement. Furthermore, the stability of the PSCs with CuFeS2 modification is improved compared with the devices without CuFeS2 modification. The efficiency of the PSCs with CuFeS2 modification maintains 93% of its initial value, whereas that of the devices without CuFeS2 modification decreases to 61% of the initial value. This work demonstrates that CuFeS2 is a novel material used as a modification layer to enhance the efficiency and stability of the PSCs.

Highly efficient and stable quasi two-dimensional perovskite solar cells via synergistic effect of dual additives.

Recently, quasi two-dimensional (Q-2D) perovskites with alternating cations in the interlayer space (ACI) have attracted more attentions owing to their elevated stability compared with three-dimensional (3D) analogs. While the efficiency of the devices derived from Q-2D perovskites is much smaller than that based on 3D perovskites. Here, we utilized urea and methoxyamine hydrochloride (MOAH) dual additives to acquire high quality Q-2D ACI perovskite GA(MA)5Pb5I16 (GA = guanidinium, MA = methylammonium) films. The efficiency of the perovskite solar cells (PSCs) derived from the Q-2D perovskite films induced by the synergistic effect of urea and MOAH dual additives increases to 20.32% from 17.21% for the devices without additive. This efficiency enhancement could be attributed to the enlarged grain size, improved crystallinity, optimized quantum well thickness distribution, and reduced trap states of the perovskite films. Moreover, the solar cells with dual additives present improved stability. The efficiency of devices with dual additives holds 95% of the original value after storage for 1600 h in ambient air. These results prove that the synergistic effect of urea and MOAH is an effective method to achieve highly efficient and stable Q-2D PSCs.

Organic carbon accumulation and aggregate formation in soils under organic and inorganic fertilizer management practices in a rice-wheat cropping system.

Soil organic carbon (C) and aggregates are the important components of soil fertility and the foundation of sustainable agriculture. The storage and protection of SOC in aggregates is widely regarded as the material basis of soil organic C accumulation. However, current understanding of soil aggregate and its associated organic C is insufficient to elucidate the regulation mechanism of soil organic C. A nine-year field experiment including chemical fertilizer (FR) and organic manure (OM) treatments was set up in the eastern plain of Funiu Mountain, central China. Using chemical analysis, physical sieving as well as nuclear magnetic resonance (NMR) methods, we mainly probed into the response of soil organic C concentration and composition, and C functional groups, water-stable aggregates to different treatments. Furthermore, scanning electronic microscopy (SEM) and partial least square structural equation modelling (PLS-SEM) was conducted to characterise the different size aggregates and to analyse the mechanism of soil organic C accumulation and stabilisation at aggregate scales. After nine years of farming, OM treatment substantially increased soil organic C content (by 3.77 g kg-1) and significantly enhanced the formation of macro-aggregates (> 250 µm), while FR had no significant influence on soil organic C. At the aggregate scale, the amounts of soil organic C, C physical fractions (particulate and mineral-associated organic C), total nitrogen and microbial biomass carbon associated in macro-aggregates (> 250 µm) were obviously higher than that in micro-aggregates and silt + clay fraction, and OM treatment greatly increased the accumulation of soil organic C and its components in macro-aggregates. Moreover, microbial biomass carbon (MBC) amounts in aggregates were remarkably increased (27-116%) by the application of OM. And MBC had a positively effect on the physical fractions of SOC but not on the C chemical structure within aggregates. The present study indicated that soil organic C accumulation mainly rely on macro-aggregates (> 250 µm). Intra-particulate organic carbon (POC) and mineral-associated organic carbon (MOC) within macro-aggregates played an important role in soil organic C accumulation. Meanwhile, soil microbes were a driving force for the accumulation of soil organic C physical fractions (POC and MOC). We concluded that OM treatment accelerated the synergistic process between organic C sequestration and soil aggregation, and showed great potential to increase soil organic C accumulation.

Analysis of clinical application effects and challenges of early warning system for the high-risk obstetric women of China: A scoping review.

BACKGROUND: Obstetric critical illness is an important factor that leads to an increase in maternal mortality. Early warning assessment can effectively reduce maternal and neonatal mortality and morbidity. However, there are multiple early warning systems, and the effect and applicability of each system in China still need to be explored. OBJECTIVES: To elaborate on the application, effectiveness and challenges of the existing early warning systems for high-risk obstetric women in China and to provide a reference for clinical practice. DESIGN: A scoping review guided by the Arksey and O'Malley framework and reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis for scoping review (PRISMA-ScR) guidelines. ELIGIBILITY CRITERIA: We included original studies related to early warning and excluded those that were guidelines, consensus and reviews. The included studies were published in Chinese or English by Chinese scholars as of June 2021. DATA SOURCES: CNKI, Wanfang, VIP, Cochrane, CINAHL, Embase, PubMed and Web of Science databases were searched systematically, and the reference sections of the included papers were snowballed. RESULTS: In total, 598 articles were identified. These articles were further refined using keyword searches and exclusion criteria, and 17 articles met the inclusion criteria. We extracted data related to each study's population, methods and results. Early warning tools, outcome indices, effects and challenges are discussed. CONCLUSIONS: Although all studies have shown that early warning systems have good application effects, the use of early warning systems in China is still limited, with poor regional management and poor sensitivity for specific obstetric women. Future research needs to develop more targeted early warning tools for high-risk obstetric women and address the current challenges in clinical applications.

Torrefaction characteristics of cellulose loaded with boric acid.

To explore the catalytic effect of boric acid on biomass, cellulose loaded with boric acid was roasted by a tubular furnace. The gaseous products were adsorbed by activated carbon and then analyzed by GC-MS. Boric acid was shown to improve the selectivity of the product levoglucosenone (LGO). The effects of the parameters such as boric acid loading, nitrogen flow, and temperature on the torrefaction behavior of cellulose were investigated. In the studied temperature range of 240-420 °C, the yield of LGO first increases and then decreases. In addition, its yield increases directly with increasing nitrogen flow rate. The results show that the highest LGO yield of 6.64% (analytical value) can be obtained under 10% (w/w) boric acid loading, 380 °C and nitrogen flow rate of 65 ml/min conditions.

High-Efficiency and Wavelength-Tunable Near-Infrared Emission of Lanthanide Ions Doped Lead-Free Halide Double Perovskite Nanocrystals toward Fluorescence Imaging.

Near-infrared (NIR) fluorescent materials show unique photophysical properties, which make them widely used in optical communication, night vision imaging, biomedicine, and other applications. However, the development of high-efficiency and wavelength-tunable NIR nanomaterials is still a challenge. Herein, a series of lanthanide ions doped Cs2AgIn0.99Bi0.01Cl6 double perovskite nanocrystals (DPNCs) with wavelength-tunable NIR light emission (800-1600 nm) have been synthesized. The optimal photoluminescence quantum yield (PLQY) of the DPNCs reaches 66.7%, which is a record value for DPNCs. It is mainly attributed to the contribution of NIR emission of lanthanide ions doped into DPNCs. More importantly, the series of NIR emission wavelengths of lanthanide ions doped Cs2AgIn0.99Bi0.01Cl6 DPNCs include not only shorter-wavelength NIR light (≤900 nm) but also longer-wavelength NIR light (>900 nm), which are more appropriate for foodstuff analysis and medical diagnosis applications. Furthermore, 11.2% Nd3+ doped Cs2AgIn0.99Bi0.01Cl6 DPNCs with the optimal PLQY were embedded in a polymethyl methacrylate (PMMA) polymer matrix (DPNCs@PMMA), and the stability of DPNCs modified by PMMA has been greatly improved. Finally, the 11.2% Nd3+ ions doped Cs2AgIn0.99Bi0.01Cl6 DPNCs@PMMA based NIR LEDs have demonstrated good night vision and human tissue penetration. This work indicates that lanthanide ions doped DPNCs have a potential in NIR light applications and could inspire future research to explore novel lanthanide ions doped semiconductor NCs based NIR LEDs.

Recent Progress in Doped g-C3N4 Photocatalyst for Solar Water Splitting: A Review.

Graphitic carbon nitride (g-C3N4) photocatalysis for water splitting is harvested as a fascinating way for addressing the global energy crisis. At present, numerous research subjects have been achieved to design and develop g-C3N4 photocatalysis, and the photocatalytic system still suffers from low efficiency that is far from practical applications. Here, there is an inspiring review on the latest progress of the doping strategies to modify g-C3N4 for enhancing the efficiency of photocatalytic water splitting, including non-metal doping, metal doping, and molecular doping. Finally, the review concludes a summary and highlights some perspectives on the challenges and future research of g-C3N4 photocatalysts.

One-step immobilization of ß-glucosidase in crude enzyme solution by recyclable UCST-responsive polymer with enhanced uniformly biocatalytic performance.

In this study, the upper critical solution temperature (UCST)-responsive polymers poly (ethylene oxide) monomethyl ether-block-poly(acrylamide-co-acrylonitrile) (PEG-b-p(AAM-co-AN) were synthesized and successfully utilized to immobilize ß-glucosidase in crude enzyme solution. These UCST-responsive ß-glucosidase biocatalysts (PEG-b-p(AAM-co-AN@LytA-Glu) have specific UCST with tunable transition temperature, which could be tuned the separation temperature to the desired temperature range. The P2 @ LytA-Glu with an UCST of about 42.9 â„ƒ was exploited by one-step covalent immobilization of ß-glucosidase in crude enzyme solution. The prepared P2 @ LytA-Glu exhibited significantly improved temperature, pH, storage, and operation stabilities compared with that of free enzyme. The catalytic rate of P2 @ Glu-LytA was 14.5% higher than that of P2-Glu (immobilized pure ß-glucosidase), which indicated that one-step immobilization of crude enzyme directly from crude enzyme solution was feasible, and it can greatly save the purification step and reduce the experimental cost. The engineered UCST-responsive immobilized enzymes are potentially useful for the practical green biocatalysis.

The potential of a natural iron ore residue application in the efficient removal of tetracycline hydrochloride from an aqueous solution: insight into the degradation mechanism.

In the existing research, most of the heterogeneous catalysts applied in the activation of persulfate to degrade organic pollutants were synthesized from chemical reagents in the laboratory. In this paper, we have obtained a spent iron ore (IO) residue directly collecting from the iron ore plants, and efficiently activating peroxydisulfate (PS) to produce reactive free radicals. The experimental results demonstrated that the IO could effectively activate PS to degrade tetracycline hydrochloride (TCH), with TCH removal rate reaching up to 85.6% within 2 h at room temperature. The TCH removal rate was increased with increasing iron ore dosage, while the more acidic pH condition would be favorable to TCH removal process. The material characterization results demonstrated that the dominant components of IO were Fe3O4 and FeOOH. The transformation from Fe(II) to Fe(III) at the surface IO was observed after TCH degradation. What's more, the quenching experiment and EPR detection results confirmed that the sulfate radical (SO4•-) and hydroxyl radicals (•OH) would be acting as the main free radicals for TCH degradation. This study could not only explore a novel way to recycle the discarded iron ore, but also further expand its application in an effective activation of PS in an aqueous solution.

Design a flower-like magnetic graphite carbon microsphere for enhanced adsorption of 2,4-dichlorophenol.

2,4-Dichlorophenol (2,4-DCP) is a hazardous chlorinated organic chemical, so its removal is an important task to protect the whole ecosystem and human health. During the material preparation, the magnetic graphitic carbon adsorbent (HFMCM) with a sparse sheet-like stacking structure was formed by interlayer assembly of nickel hydroxide nanosheets and hydrothermal glucose carbon. The conditions for optimal performance of the adsorbent are 45 °C and pH 5. The maximum adsorption capacity of HFMCM-180 for 2,4-DCP is 147.06 mg·g-1. Adsorption behavior in accordance with Langmuir isothermal model and pseudo-second-order kinetic models. The adsorbent remains selective for 2,4-DCP in metal ion solutions. More than 75% of the adsorption capacity is maintained after five cycles of adsorption. Electrostatic interaction, hydrogen bonding, and π-π bonding play a major role in the adsorption of 2,4-DCP by HFMCM. The adsorbent was glucose as the carbon source, nickel sulfate as the magnetic source, and hexamethylenetetramine as the precipitant. Its carbonization after pretreatment with different hydrothermal temperatures resulted in the synthesis of flower-like graphitic carbon spheres with magnetic properties. The interconnected pore channels on the adsorbent surface conferred large specific surface area to the material. 2,4-DCP was efficiently adsorbed by π-π stacking, hydrogen bonding, and electrostatic attraction within the pore channels with low spatial potential resistance.

Highly efficient and stable red perovskite quantum dots through encapsulation and sensitization of porous CaF2:Ce,Tb nanoarchitectures.

Lead halide perovskite quantum dots (PQDs) are extremely unstable when exposed to oxygen, water and heat, especially red CsPbBrxI3-x (x = 0, 0.5, 1.2) PQDs. This seriously hinders their practical application. Here, red CsPbBrxI3-x (x = 0, 0.5, 1.2) PQDs have been successfully encapsulated in porous CaF2:Ce,Tb hierarchical nanospheres (HNSs), which not only greatly improved the stability of PQDs, benefitting from the protection of the CaF2 shell, but also maintained the high photoluminescence quantum yield (PLQY) of PQDs, benefitting from the sensitization of Tb3+ ions. More importantly, porous CaF2:Ce,Tb nanoarchitectures can prevent aggregation quenching and anion exchange of PQDs. Therefore, the CaF2:Ce,Tb&CsPbBrxI3-x (x = 0, 0.5, 1.2) composite powder can have high PLQY comparable to that of the PQD powder. In view of this, CaF2:Ce,Tb&CsPbBr1.2I1.8 composite based red light-emitting diodes (LEDs) are prepared, and they are very suitable as a supplementary light source for plant lighting. Furthermore, white LEDs are also prepared by coating the CaF2:Ce,Tb&CsPbBr3 and CaF2:Ce,Tb&CsPbBr1.2I1.8 composite on a 450 nm chip. The optimum luminous efficiency is 61.2 lm W-1, and the color rendering index is 91, which are comparable to the current highest values. This shows that the composite composed of PQDs has great potential in LED lighting.

UV-assisted nitrogen-doped reduced graphene oxide/Fe3O4 composite activated peroxodisulfate degradation of norfloxacin.

We reported the preparation of NGO-Fe3O4 by simple hydrothermal-co-precipitation. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). It was demonstrated that norfloxacin (NOR) could be effectively degraded by the UV/NGO-Fe3O4/PDS system. The degradation efficiency reached 100% within 13 min (the concentration of NOR and S2O82- were 100 mg L-1 and 1 mM, respectively; m(NGO-Fe3O4): m(PDS) = 4: 1; pH: 3.0). In addition, NGO-Fe3O4 showed stable catalytic activity in recycling. The analysis found that the in-situ generated ·OH was the main active free radicals but SO4-⋅ also participated in the NOR degradation. Based on the identified intermediates, the NOR degradation pathways were proposed with UV/NGO-Fe3O4/PDS system.

A novel enhanced enrichment glucose oxidase@ZIF-8 biomimetic strategy with 3-mercaptophenylboronic acid for highly efficient catalysis of glucose.

Herein, a glucose oxidase@ZIF-8 composite (3-MPBA/GOx@ZIF-8) with enhanced enrichment was enabled the rapid encapsulation of glucose oxidase (GOx) into microporous zeolitic imidazolate framework-8 (ZIF-8) for the first time. The 3-MPBA/GOx@ZIF-8 not only has improved affinity and catalytic efficiency to the substrate but also can shorten the formation time. The optimum loading amount of GOx on ZIF-8 was determined to be 470 mg/g. The as-prepared 3-MPBA/GOx@ZIF-8 composite maintained the native conformation of the enzyme and showed excellent bioactivity, even in chemical agents or at high temperature. Furthermore, the 3-MPBA/GOx@ZIF-8 showed satisfactory reusability, preserving almost 80.8 % activity after 7 cycles. The Michaelis constant Km and specificity constant kcat/Km of the 3-MPBA/GOx@ZIF-8 were 0.03 ±â€¯0.02 mM and 63.87 ±â€¯1.96 s-1 mM-1, respectively, which were superior to corresponding values of free GOx. Therefore, the 3-MPBA/GOx@ZIF-8 displayed high catalytic efficiency, high loading efficiency and enhanced stability. Moreover, a new type of visual colorimetric sensor for screening of the diabetes was realized through the 3-MPBA/GOx@ZIF-8, which provided a new strategy for the analysis field of glucose.

Occurrence, Profiles and Ecological Risk of Bisphenol Analogues in a Municipal Sewage Treatment Plant.

Due to the strict control on bisphenol A (BPA) in many countries, bisphenol analogues (BPs) are being widely used as alternative materials to manufacture epoxy resins and polycarbonate plastics, resulting in their occurrence in sewage treatment plants (STPs). In this study, the occurrence and distribution of 7 BPs in a large-scale STP in Beijing China was investigated. Wastewater samples were collected from the influents and effluents of each processing unit, and extracted by solid-phase extraction. Target compounds were quantified by ultra-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The total concentrations of seven BPs (ΣBPs) were 400.42 ± 48.12 ng/L in the raw sewage, 438.60 ± 46.50 ng/L in the primary effluent, 17.21 ± 13.12 ng/L in the secondary effluent, and 11.33 ± 4.84 ng/L in the tertiary effluent, respectively. Bisphenol S (BPS) and BPA were the predominant congener in raw sewage with an overall contribution of 29.32% and 70.22% to the ΣBPs, indicating that there was a large amount of BPS and BPA consumption in the study area. During a one-week sampling period, ΣBPs changed slightly at the same sampling site. It was found that high removal efficiencies were achieved for BPs in anoxic and oxic secondary clarifier treatment units, suggesting that biodegradation and sorption played major roles in BPs elimination in the STP. After tertiary treatment, all BPs except BPA were completely removed, suggesting the necessity to investigate the fate and toxicity of BPA in the aquatic environment.

High-Performance Perovskite Solar Cells Based on NaCsWO3@ NaYF4@NaYF4:Yb,Er Upconversion Nanoparticles.

Extending photoelectric response to the near-infrared (NIR) region using upconversion luminescent (UCL) materials is one promising approach to obtain high-efficiency perovskite solar cells (PSCs). However, challenges remain due to the shortage of highly efficient UCL materials and device structure. NaCsWO3 nanocrystals exhibit near-infrared absorption arising from the local surface plasmon resonance (LSPR) effect, which can be used to boost the UCL of rare-earth-doped upconversion nanoparticles (UCNPs). In this study, using NaCsWO3 as the LSPR center, NaCsWO3@NaYF4@NaYF4:Yb,Er nanoparticles were synthesized and the UCL intensity could be enhanced by more than 124 times when the amount of NaCsWO3 was 2.8 mmol %. Then, such efficient UCNPs were not only doped into the hole transport layer but also used to modify the perovskite film in PSCs, resulting in the highest power conversion efficiency (PCE) reaching 18.89% (that of the control device was 16.01% and the PCE improvement was 17.99%). Possible factors for the improvement of PSCs were studied and analyzed. It is found that UCNPs can broaden the response range of PSCs to the NIR region due to the LSPR-enhanced UCL and increase the visible light reabsorption of PSCs due to the scattering and reflection effect, which generate more photocurrent in PSCs. In addition, UCNPs modify the perovskite film by effectively filling the holes and gaps at the grain boundary and eliminating the perovskite surface defects, which lead to less carrier recombination and then effectively improve the performance of PSC devices.