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Dopamine-functionalized upconversion nanoparticles as fluorescent sensors for organophosphorus pesticide analysis
摘要： Organophosphorus pesticide (OP) residues in agricultural products, herbal medicines and environment have attracted increasing concerns because they cause high healthy risk. Herein, a tyrosinase-mediated photoinduced electron transfer system was constructed for OPs analysis by using dopamine-functionalized upconversion nanoparticles (UCNPs) as fluorescent (FL) sensors. Dopamine quinone was produced by tyrosinase-mediated oxidation of dopamine on the surface of UCNPs, which acted as electron accepter to quench the FL emission of UCNPs. The FL quenching was inhibited by OP since it inhibited the activity of tyrosinase. Chlorpyrifos was used as a model analyte to investigate the feasibility of the FL sensor for the analysis of OPs. Under the optimal conditions, chlorpyrifos can be analysed in a wide range of 1.0 ? 1000 ng mL?1, with a detection limit of 0.38 ng mL?1 (3σ). Some other groups pesticides, including organonitrogen pesticide, organochlorine pesticide and chloronicotinyl insecticide all showed negligible interference. The proposed sensor was successfully used to analyse chlorpyrifos spiked in Balloonflower and Angelica with acceptable recovery values of 95.4–120.0%, demonstrating its application potential for real samples. It exhibits some advantages like low cost, high sensitivity and free of autofluorescent interference and photobleaching.
关键词： Tyrosinase,Photoinduced electron transfer,Fluorescent sensor,Organophosphorus pesticide,Upconversion nanoparticles,Chlorpyrifos
更新于2025-11-14 17:15:25
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Organic Solar Cells Efficiency Enhanced by Perylene Mono-Imide Phosphorus Salt Cathode Interfacial Layer
摘要： The composite high-performance electrode is very important for excellent photoelectric device. Interfacial modification is the dominating method to optimize electrode properties. Two easy synthesized perylene-monoimide (PMI) derived organic phosphonium bromide salts were found interestingly valuable when they were applied as cathode interlayers (CIL) in bulk heterojunction (BHJ) organic solar cells (OSCs). Using the PBDB-T:ITIC blend as bulk-hererojunction active layer in inverted device structure, the power conversion efficiency (PCE) was greatly improvement from 9.49% of the referenced device which is without phosphonium CIL to PCE 10.42% with PMI-triphenyl-phosphonium bromide (PMI-TPP) and PCE 9.87% with PMI- trimethoxylphenylphosphonium bromide (PMI-TMOPP) as CIL. Moreover, the two organic phosphonium bromide salts were also investigated by traditional device structure, the PCE was of 4.21% for bare aluminium cathode referenced device contrasted to a moderate increased PCE of 5.18% with PMI-TPP CIL or PCE of 5.05% with PMI-TMOPP CIL. Therefore, organic phosphonium bromide salt PMI-TPP is a promising candidate of CIL material in OSCs.
关键词： cathode interlayer,organophosphorus,energy conversion,electron transfer,solar cell
更新于2025-09-23 15:21:01
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Fluorescence sensor for facile and visual detection of organophosphorus pesticides using AIE fluorogens-SiO2-MnO2 sandwich nanocomposites
摘要： Organophosphorus pesticides (OPs) are frequently for pest control in the agriculture industry. Accumulation of OPs is harmful to the environment and human health. Thus, facile and portable detection of organophosphorus pesticides is of great importance. Among these methods, the fluorescence assay holds the advantages of high sensitivity, simplicity, nondestructive properties. Conventional fluorophores have the drawbacks of poor photostability and low signal-to-noise ratio due to their aggregation-caused quenching drawbacks at high concentration or in the aggregate state. Aggregation-induced emission fluorogens (AIEgens) are one key to develop next-generation fluorescence sensor due to their high emission efficiency in the aggregated state. 1,2-bis[4-(3-sulfonatopropoxyl) phenyl]-1,2-diphenylethene (BSPOTPE) is a typical AIE molecule containing two hydroxyl group. In this study, a fluorescence sensor based on BSPOTPE-SiO2–MnO2 sandwich nanocomposites was fabricated. Thiocholine (TCh), which produced from acetylthiocholine(ATCh) by the hydrolysis of acetylcholinesterase (AChE), can “turn on” the fluorescence sensor. Based on the inhibition effect of OPs on AChE activity and the corresponding “turn off” effect on the fluorescence sensor, an AIE-based assay for OPs determination was developed. The fabricated sensor for paraoxon determination has a good linear relationship in the range of 1–100 μg/L and the LOD of 1 μg/L. Moreover, a simple, convenient fluorescence strip for visual semi-quantitative of OPs was fabricated, indicating this “on-off” fluorescent sensor is promising for on-site and infield detection.
关键词： Organophosphorus pesticide,AIE fluorogen,Fluorescence sensor,MnO2 nanosheets
更新于2025-09-19 17:15:36
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Efficient defect-passivation and charge-transfer with interfacial organophosphorus ligand modification for enhanced performance of perovskite solar cells
摘要： Interfacial engineering is an effective method to improve the performance of perovskite solar cells. Nevertheless, it is still challenging to find a material as interfacial layer with the dual function of defect-passivation and efficient charge-transfer. In this work, organophosphorus ligands, trioctylphosphine oxide (TOPO) and triphenylphosphine oxide (TPPO), were used as passivators through antisolvent process for the interfacial modification. Significantly, the organophosphorus ligands can effectively passivate the defects of perovskite crystals through the formation of Pb–O bond between organophosphorus ligand and undercoordinated Pb2t ion in perovskite. More interestingly, benzene rings with π electron in TPPO facilitate the charge transfer between perovskite and hole-transporting layer, achieving the best power conversion efficiency of 18.29% with negligible hysteresis, as well as excellent long-term stability with remaining nearly 85% of the initial efficiency after 2000 h storage under 50% humidity ambient air. In contrast, uncharged octyl alkanes in TOPO hinder the charge transfer and lead to the accumulation of charges at interface although it is a good passivator in light emitting devices for charge confinement. Our findings shed light on the importance of efficient transfer when defect-passivation is employed in solar cell.
关键词： Organophosphorus ligand,Charge-transfer,Defect-passivation,Perovskite solar cell
更新于2025-09-19 17:13:59
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Plasmon-active optical fiber functionalized by metal organic framework for pesticide detection
摘要： Functional plasmonic fiber for detection and on-line monitoring of organophosphorus pesticides in water or model soil samples is described. The appearance of the plasmon absorption band was realized through the deposition of a thin gold layer on the naked core of multimode optical fiber. The metalorganic frameworks (MOF-5) layer was deposited on the gold surface for the introduction of a high affinity towards the target pesticides. The MOF-5 layer affords the extraction of pesticides and their concentration primarily in the “plasmon evanescent wave” space, allowing the detection by the shift of plasmon absorption band. The growth of MOF-5 layer was confirmed using the Raman, XPS and XRD measurements. The entrapping of pesticides was checked using the Raman spectroscopy and ellipsometry, which also indicate the corresponding changes of MOF-5 refractive index. The series of further experiments demonstrate the applicability of proposed fiber sensor for detection of pesticides in soil without the false signals from surrounding media. The main advantages of proposed sensor can be attributed to simplicity, high sensitivity, low cost and the absence of organic solvents for the probe treatment.
关键词： Optical fiber,Organophosphorus pesticides detection,Metal–organic frameworks,Surface plasmon resonance,Sensor
更新于2025-09-12 10:27:22
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Magnesium and nitrogen co-doped carbon dots as fluorescent probes for quenchometric determination of paraoxon using pralidoxime as a linker
摘要： Carbon dots codoped with magnesium and nitrogen (Mg,N-CDs) were synthesized via a one-step microwave-assisted method. They display blue fluorescence (with excitation/emission peaks at 380/460 nm and a 33% quantum yield) and possess high dispersity in aqueous solution. The fluorescence of the Mg,N-CDs is highly sensitive to paraoxon in the presence of pralidoxime (PAM) acting as the linking agent. Electron transfer from Mg,N-CDs to paraoxon in the presence of PAM leads to the fluorescence quenching of Mg,N-CDs. The concentration of paraoxon is determined by measuring the quenching efficiency of the Mg,N-CD-PAM assay system. Fluorescence drops with increasing concentrations of paraoxon in the 0.005–3.0 μM range, and the limit of detection is 0.87 nM. The method is highly selective for paraoxon even in the presence of possible interferences. Real sample study of tap and river water showed the assay to have good repeatability and accuracy.
关键词： Quantum yield,Oxime,Electron transfer,Fluorescence quenching,Organophosphorus pesticides
更新于2025-09-04 15:30:14