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New one-dimensional mercury(II) coordination polymers built up from dispiro-dipyridyloxy-cyclotriphosphazene: Structural, thermal and UV-vis absorption properties
摘要： Reactions of flexible polydendate ligand system dispiro-dipyridyloxy-cyclotriphosphazene (L) with a variety of mercury(II) salts (HgX2) (X= I￣, Cl￣) afforded two one-dimensional mercury(II) coordination polymers, namely formulated as {[Hg(L)(I)2]}n (1) and {[Hg(L)(Cl)2]}n.(ACN)0,341 (2). The isolated crystalline compounds were structurally characterized by elemental analysis and single crystal X-ray crystallography. The X-ray crystal structure analysis revealed that 1 and 2 crystallizes in the orthorhombic (space group Pccn) and the monoclinic crystal system (space group P21/c), in which L exhibited a κ2N coordination binding mode with the divalent Hg ions to form one-dimensional chain structures. The central Hg2+ ion in 1 and 2 has a distorted tetrahedral coordination geometry. UV-Vis properties and thermal stability of L and complexes (1, 2) were also investigated. UV-Vis experiments (titration and continuous variation (Job’s plot) analysis) showed that all of spectrophotometric properties in solution state supports crystal structure of complexes. According to TGA analysis, coordination polymers exhibited thermal stability up to 300 °C, but L showed more thermal stability than 1 and 2.
关键词： JOBS Diagram,Pyridyloxy Cyclotriphosphazene,Hg2+ Coordination Polymers,UV-Vis Absorption,1D Coordination Polymers
更新于2025-09-23 15:23:52
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Study on Five Porphyrin-Based Photosensitizers for Singlet Oxygen Generation
摘要： Five porphyrin derivatives were synthesized and characterized in order to be utilized as photosensitizers for singlet oxygen generation. UV-Vis absorption properties of porphyrins were experimentally and theoretically discussed. The results indicated that the increase in π-conjugation of porphyrin core can lower the S1-T1 energy gap and is favorable for efficient energy transfer. The singlet oxygen generation ability of porphyrins was measured and compared under both simulated sunlight and yellow light. As for the results using simulated sunlight, EBHPP and CEBHPP exhibited best and similar performance because they bear strong near-IR absorption and S1-T1 interactions. However, under yellow light conditions CEBHPP has better ability for singlet oxygen generation because of strong absorbance from 650–750 nm. The DNA photocleavage measurements were performed to evaluate the biological activity of the porphyrin derivatives. The photocleavage activities were in the order of TPP < TPP-NO2 < BHPP < EBHPP < CEBHPP, and the possible reasons were discussed. This work is useful for the design of more efficient photosensitizers.
关键词： Photosensitizer,Porphyrin,Singlet oxygen,UV-Vis absorption,Photodynamic therapy
更新于2025-09-23 15:22:29
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Optical aptasensor based on silver nanoparticles for the colorimetric detection of adenosine
摘要： A new and straightforward optical sensor for the colorimetric determination of adenosine (AD) in human urine samples was developed. The sensor comprised silver nanoparticles (AgNPs) as colorimetric elements and anti-AD aptamer (AP) as a recognition probe. In a solution containing AD and high concentration of NaCl, due to the unique binding of AD with AP, the aggregated metal nanomaterials dispersed in the solution, and the color intensity of the solution was changed accordingly. The absorbance of the solution was monitored for AD quantification. The method was applicable for the determination of AD in the concentration range of 60–280 nM with the detection limit of 21 nM. The relative standard deviation ranged from 4.8 to 8.8% for six replicates. The method showed excellent selectivity toward AD checked over some probable interfering compounds. To investigate the performance of AgNPs, the analytical characteristics of the method including linear range, detection limit, selectivity, and precision were compared with those obtained by a common AuNPs-based aptasensor. The reliability of the method was further ascertained for the detection of AD in urine samples of two lung cancer patients with percentage recoveries in the range of 98–107%.
关键词： Adenosine,Silver nanomaterials,Colorimetric,UV–vis absorption spectroscopy,Aptamer
更新于2025-09-23 15:22:29
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Deep Learning for Optoelectronic Properties of Organic Semiconductors
摘要： Atomistic modeling of the optoelectronic properties of organic semiconductors (OSCs) requires a large number of excited-state electronic-structure calculations, a computationally daunting task for many OSC applications. In this work, we advocate the use of deep learning to address this challenge and demonstrate that state-of-the-art deep neural networks (DNNs) are capable of accurately predicting various electronic properties of an important class of OSCs, i.e., oligothiophenes (OTs), including their HOMO and LUMO energies, excited-state energies and associated transition dipole moments. Among the tested DNNs, SchNet shows the best performance for OTs of different sizes, achieving average prediction errors in the range of 20-80meV. We show that SchNet also consistently outperforms shallow feed-forward neural networks, especially in difficult cases with large molecules or limited training data. We further show that SchNet could predict the transition dipole moment accurately, a task previously known to be difficult for feed-forward neural networks, and we ascribe the relatively large errors in transition dipole prediction seen for some OT configurations to the charge-transfer character of their excited states. Finally, we demonstrate the effectiveness of SchNet by modeling the UV-Vis absorption spectra of OTs in dichloromethane and a good agreement is observed between the calculated and experimental spectra.
关键词： optoelectronic properties,organic semiconductors,transition dipole moment,SchNet,oligothiophenes,deep learning,UV-Vis absorption spectra
更新于2025-09-23 15:19:57
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Theoretical study of the excited state properties of luminescent phospholes
摘要： TD-DFT calculations with the use of hybrid PBE0 functional and def-TZVP Alrich’s basis set are shown to provide an excellent cost-effective computational approach for the treatment of the excited states of phospholes. The general geometrical changes taking place upon excitation and bearing a common character in the series of considered phospholes have been revealed. It is demonstrated that conjugation of P-heterol with exocyclic aryl fragments makes the main impact on the ground-state (electronic absorption) properties of phospholes. The main structural transformations of the excited states responsible for emission properties are shown to occur mostly inside the P-hetorole ring causing change in bonds ordering upon excitation. The general good agreement between the experiments and the calculations found for the considered systems suggests that the applied theoretical approach can be used as an effective predictive tool for the rational design of luminescent phospholes.
关键词： phospholes,excited states properties,TD-DFT,UV-vis absorption/emission
更新于2025-09-19 17:15:36
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Alkali-metal-controlled changes of stability and NLO properties in ideal unscrewing process of double helix
摘要： Molecular machines were attractive for scientists due to their excellent dynamical properties and potential applications. Inspired by the feature of molecular machine, we designed an ideal unscrewing process of double-chain sexipyridine complex with four conformations and explored the variation of stability and optical properties. As a result, we found the double helices where the fragments bound by only weak π-π interaction had poor stability. Thus the conformation with stronger π-π interaction was more stable than others. But this could be changed by adding alkali metals, and different alkali metal atoms such as Li and Na could control the stability order because of their different atomic radii. For Li-doped molecules, Li-1 with tightly coiled strands was the most stable conformation. While for Na-doped molecules, Na-4 with unscrewed fragments was the most stable one. This mainly resulted from the intra-molecular interaction potential energy especially the interaction between metal and ligand. At the same time, the charge distribution showed corresponding variation. In the aspect of optical properties, the unscrewing process was followed by the variation of absorption intensity at about 500 nm in the UV–Vis absorption spectra because of the conformation change. Meanwhile, the first-order static hyperpolarizability (βtot) showed zigzag variation due to the change of frontier molecular orbital energy gap in the unscrewing process.
关键词： (un)screwing,NLO,Alkali metal doping,UV–Vis absorption,Double helix
更新于2025-09-16 10:30:52
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Fabrication of Interconnected Plasmonic Spherical Silver Nanoparticles with Enhanced Localized Surface Plasmon Resonance (LSPR) Peaks Using Quince Leaf Extract Solution
摘要： Interconnected spherical metallic silver nanoparticles (Ag NPs) were synthesized in the current study using a green chemistry method. The reduction of silver ions to Ag NPs was carried out with low-cost and eco-friendly quince leaves. For the first time, it was confirmed that the extract solution of quince leaves could be used to perform green production of Ag NPs. Fourier transform infrared spectroscopy (FTIR) was conducted to identify the potential biomolecules that were involved in the Ag NPs. The results depicted that the biosynthesis of Ag NPs through the extract solution of quince leaf was a low-cost, clean, and safe method, which did not make use of any contaminated element and hence, had no undesirable effects. The majority of the peaks in the FTIR spectrum of quince leaf extracts also emerged in the FTIR spectrum of Ag NPs but they were found to be of less severe intensity. The silver ion reduction was elaborated in detail on the basis of the FTIR outcomes. In addition, through X-ray diffraction (XRD) analysis, the Ag NPs were also confirmed to be crystalline in type, owing to the appearance of distinct peaks related to the Ag NPs. The creation of Ag NPs was furthermore confirmed by using absorption spectrum, in which a localized surface plasmon resonance (LSPR) peak at 480 nm was observed. The LSPR peak achieved in the present work was found to be of great interest compared to those reported in literature. Field emission scanning electron microscopy (FESEM) images were used to provide the morphology and grain size of Ag NPs. It was shown from the FESEM images that the Ag NPs had interconnected spherical morphology.
关键词： FESEM study,FTIR study,XRD analysis,UV–Vis absorption,quince leave,silver nanoparticles
更新于2025-09-12 10:27:22
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Synthesis of gold nanoparticles by pulsed laser-assisted reduction of aqueous gold precursor
摘要： In this paper, colloidal gold nanoparticles (GNPs) were synthesized by Nd:YAG (λ = 1064 nm) pulsed laser-assisted reduction (PLAR) of aqueous [AuCl4]?. In this process, during laser ablation of a Mo target in DI water, a [AuCl4]? precursor solution was being added dropwise in situ. UV–Vis absorption spectra showed distinct plasmonic absorption bands at 209 and 530 nm corresponding to Mo nanoparticles (NPs) and GNPs, respectively. Furthermore, no significant conversion for [AuCl4]? was found when it was added to aged Mo NPs or when it was irradiated in the lack of the Mo target. Using transmission electron microscope (TEM) images, it was found that precursor concentration and laser-ablation time can affect the population or size of GNPs. In PLAR with a small amount of KI solution in water, the GNPs size increases to ~ 50 nm via an iodine-induced particle fusion mechanism. The reduction mechanism was discussed based on metastable species intercation, producing the cavitation bubble during laser ablation.
关键词： Mo target,Nd:YAG laser,TEM,UV–Vis absorption,Pulsed laser-assisted reduction,Gold nanoparticles,KI solution
更新于2025-09-11 14:15:04
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Single-step formation of Cr 2 N nanoparticles by pulsed laser irradiation
摘要： Chromium nitride nanoparticles with mean diameter distribution between 0.8 nm and 30 nm were produced by laser irradiation of a chromium target immersed in liquid nitrogen. Cr was directly converted to chromium nitride nanoparticles according to selected-area electron diffraction analyses using the transmission electron microscopy technique. Crystalline nanoparticles mostly consist of Cr2N, which is commonly reported together with the conversion of Cr2N to CrN and the mixture of chromium oxides. In addition, there is no evidence of oxidation by storage or photodegradation of the nanoparticles in isopropyl alcohol suspensions. The intensity profile of small-angle X-ray scattering indicates that the geometrical shape of the nanoparticles is not spherical but cylindrical with aspect ratio (height-to-radius) of 0:35–0:05. UV-Vis absorption spectroscopy reveals the presence of surface plasmon absorption at the ultraviolet region at wavelengths of 350, 372, and 397 nm. First-principles calculations of density of states, dielectric function, and optical conductivity performed within the theoretical framework of density functional theory for Cr2N with a hexagonal structure corroborate the formation of surface plasmons.
关键词： transmission electron microscopy,liquid nitrogen,chromium nitride nanoparticles,density functional theory,laser irradiation,UV-Vis absorption spectroscopy
更新于2025-09-11 14:15:04
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High-Performance Organic Photodetectors by Introducing a Non-Fullerene Acceptor to Broaden Long Wavelength Detective Spectrum
摘要： We demonstrate the broadband visible organic photodetectors (OPDs) by introducing a non-fullerene acceptor of 3,9-bis(2-methylene-(3-(1,1dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3d:2,3′-d′]-s-indaceno[1,2-b:5,6-b′]dithiophene (ITIC) into the bulk heterojunction (BHJ) based on a conventional system of poly(3-hexylthiophene-2,5-diyl) (P3HT):[6,6]-phenyl C71-butyric acid methyl ester (PC71BM) .The resultant OPDs exhibit a specific detectivity beyond 1012 Jones in the whole visible region ranged from 380 nm to 760 nm, and the highest detectivity reaches 2.67 × 1012 Jones at 710 nm. UV-Vis absorption spectrum, steady-state photoluminescence, atomic force microscopy, and space-charge-limited current property were applied to analyze the film characteristics of obtained OPDs. Owing to the long-wavelength absorption band of ITIC, the spectral photodetection range has been broadened effectively, and better film morphology, more effective energy transfer, and the reduced electron mobility in the active layer are responsible for the excellent photodetection capability. The proposed scheme provides a reliable strategy for implementing high-performance broadband visible OPDs.
关键词： Organic photodetectors,UV-Vis absorption,Non-fullerene acceptor,Surface morphology,Full visible light photodetection
更新于2025-09-11 14:15:04