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“Turn off-on” fluorescent sensor based on quantum dots and self-assembled porphyrin for rapid detection of ochratoxin A
摘要： We report herein a “turn off-on” fluorescent sensor based on ZnCdSe quantum dots (ZnCdSe QDs) and self-assembled zinc porphyrin for sensitive and rapid detection of ochratoxin A (OTA). Using environmentally friendly dodecyl dimethyl betaine as “soft template”, zinc 5, 10, 15, 20-tetra(4-pyridyl)-21H-23H-porphine (ZnTPyP) was self-assembled into nanorods (SA-ZnTPyP) through a green process. The OTA detection process involves two steps: (1) the fluorescence of ZnCdSe QDs is significantly quenched by SA-ZnTPyP, and (2) the combination between SA-ZnTPyP and OTA releases ZnCdSe QDs from their quenchers such that the fluorescence is recovered. Under the optimized experimental conditions, the newly developed fluorescent sensor showed a linear response in concentration range 0.5–80 ng mL?1, with a detection limit of 0.33 ng mL?1. The excellent applicability of the system has been verified in milk and coffee samples, with relative recoveries between 98.33% and 103.70%. The proposed fluorescent sensor exhibits excellent selectivity and high sensitivity, and thus could be a promising tool for on-site determination of OTA in food safety control and environmental monitoring.
关键词： Turn off-on,Self-assembled zinc porphyrin,Ochratoxin A,Quantum dots
更新于2025-09-16 10:30:52
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Higha??Efficiency Lowa??Temperaturea??Processed Mesoscopic Perovskite Solar Cells from SnO <sub/>2</sub> Nanorod Selfa??Assembled Microspheres
摘要： Mesoporous scaffolds in perovskite solar cells (PSCs) can accelerate the formation of heterogeneous nucleation sites, leading to enhanced quality of perovskite films and uniform perovskite coverage over large areas. Nevertheless, the mesoporous electron transport layers (ETLs) can effectively compensate for the drawback of shorter electron diffusion lengths than their hole counterparts. Therefore, most mesoscopic PSCs usually show superior photovoltaic performance to their planar counterparts. However, mesoporous ETLs, particularly those prepared with metal oxide nanocrystals, often require a high-temperature sintering process for the removal of residual organics and the improved crystallization of metal oxides. Here, a novel emulsion-based bottom-up self-assembly strategy is used to prepare sizable SnO2 microspheres from oleic acid capped SnO2 nanorods. Combined with an in-situ ligand-stripping strategy, the low-temperature solution-processed mesoscopic PSCs can achieve efficiency as high as 21.35% with slight hysteresis and good reproducibility. In particular, the emulsion-based bottom-up self-assembly strategy is a general way for preparing microspheres from several kinds of semiconductor nanocrystals, so it will greatly expand the material selection range for preparing efficient mesoscopic PSCs and even inverted mesoscopic devices.
关键词： mesoscopic perovskite solar cells,in situ ligand stripping,low-temperature process,SnO2 nanorod self-assembled microspheres
更新于2025-09-16 10:30:52
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Broad spectrum light-trapping ternary polymer solar cells based on self-assembled nano-ridged active layer
摘要： Ternary blend polymer solar cells (TPSCs) comprising one donor and two fullerene acceptors is efficient method for improving the power conversion efficiency (PCE). In this paper, the PTB7-Th-based TPSCs which is incorporating PC70BM and PC60BM as mixed acceptors are fabricated and investigated. Impressively, the remarkable self-assembled nano-ridged (SANR) structures are discovered in the active layer with the weight ratio of 50% PC60BM in fullerenes. Thanks to the enlarged interface area, enhanced light absorption and balanced carrier transport, the PTB7-Th:PC70BM:PC60BM TPSCs with the SANR active layer gives an optimal PCE of 9.68%. In addition, it is worth emphasizing that by combining the textured-ZnO with the SANR active layer, a double ridge superimposed system (DRSS) with broad spectrum light trapping characteristic is constructed, which can further enhance the light absorption of the devices. Finally, benefiting from the further increase in short circuit current density (Jsc), the PTB7-Th:PC70BM:PC60BM TPSCs with the DRSS gives an optimal PCE of 10.68%. This work provides a feasible ternary strategy to increase the devices performances and is proved be a simple and efficient strategy for fabricating PTB7-Th:PC70BM:PC60BM TPSCs with SANR active layer.
关键词： Self-assembled nano-ridged structure,Ternary polymer solar cell,Broad spectrum light trapping,Double ridge superimposed system
更新于2025-09-16 10:30:52
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Light-Driven Redox Activation of CO <sub/>2</sub> - and H <sub/>2</sub> -Activating Complexes in a Self-Assembled Triad
摘要： We report a self-assembled triad for artificial photosynthesis comprised of a chromophore, carbon-dioxide reduction catalyst, and hydrogen-oxidation complex, which is designed to operate without conventional sacrificial redox equivalents. Excitation of the zinc–tetraphenylporphyrin chromophore of the triad results in ultrafast charge transfer between a tungsten–alkylidyne donor and a rhenium diimine tricarbonyl acceptor, producing a charge-separated state that persists on the timescale of tens of nanoseconds and is thermodynamically capable of the primary dihydrogen and carbon dioxide binding steps for initiating the reverse water-gas shift reaction. The charge-transfer behavior of this system was probed using time-resolved fluorescence and transient absorption spectroscopy in the visible, near-infrared, and mid-infrared spectral regions. The behavior of the triad was compared to that of the zinc porphyrin–rhenium diimide dyad; the triad was found to have a significantly longer charge-separated lifetime than other previously reported porphyrin–rhenium diimine compounds.
关键词： artificial photosynthesis,zinc–tetraphenylporphyrin,charge transfer,reverse water-gas shift reaction,rhenium diimine tricarbonyl,self-assembled triad
更新于2025-09-12 10:27:22
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Interfacial Engineering through Chloride-Functionalized Self-Assembled Monolayers for High-Performance Perovskite Solar Cells
摘要： The family of organic-inorganic hybrid perovskite (OIHPs) materials is one of the most promising for very high efficiency photovoltaic solar cells application. In the present work, the effect of a series of self-assembled monolayers placed at the TiO2-perovskite junction, on the functioning of triple cation perovskite solar cells has been investigated. We show that employing 4-chlorobenzoic acid leads to the marked boosting of the solar cells performances. The starting pristine cell had a 20.3% power conversion efficiency (PCE) and the chemical engineering permitted to reach a PCE up to 21.35%. Our experimental study completed by density functional theory (DFT) calculations and modelling show that this improvement is due to the reduction of interfacial states, to the improvement of the quality of the OIHP material and to the structural continuity between TiO2 and the OIHP. Especially, we demonstrate that the interfacial chemical interactions are important to consider in the design of highly efficient devices.
关键词： Perovskite solar cells,Self-assembled monolayers,Hydrides,Benzoic acid derivatives,High efficiency,Density functional theory
更新于2025-09-12 10:27:22
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Ion irradiation of III–V semiconductor surfaces: From self-assembled nanostructures to plasmonic crystals
摘要： Ion-irradiation of semiconductor surfaces has emerged as a promising approach to generate a variety of self-organized nanostructures. Furthermore, the combination of focused-ion-irradiation with molecular-beam epitaxy provides unprecedented design and control of surfaces and interfaces of hybrid materials at the atomic level during fabrication. In this review, we describe the directed self-assembly of nanostructure arrays ranging from islands to nanorods to 3-dimensional nanoparticle (NP) arrays. First, we discuss focused-ion-irradiation of III–V surfaces, which leads to preferential sputtering of group V species, followed by the formation of group III-rich metallic nanostructures. For continued irradiation beyond a threshold dose, the nanoparticle (NP) evolution is determined by the sputtering yield and the local ion beam angle of incidence, resulting in arrays of nanoparticles, nanorods, or nanoparticle chains. In addition to describing the formation of close-packed embedded Ga:GaAs nanocomposites using overgrowth of focused-ion-beam fabricated NP arrays, we discuss the surface plasmon resonances of NP arrays as well as the influence of both surface and buried NP arrays on the GaAs photoluminescence efficiency. Finally, we discuss the potential of “plasmonic crystals” for plasmon-enhanced optoelectronics.
关键词： self-assembled nanostructures,ion irradiation,plasmonic crystals,molecular-beam epitaxy,III-V semiconductor,nanoparticle arrays,surface plasmon resonances,photoluminescence efficiency,focused-ion-beam
更新于2025-09-12 10:27:22
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Nitrogen oxides sensing performance of thiols and dithiols self-assembled monolayer functionalized Au/GaAs-based Schottky diodes
摘要： In this work, GaAs-based Schottky diodes, functionalized by alkanethiolates, were used to fabricate NOx gas sensors with high-selectivity and low-power. Alkanethiolates were employed to form a self-assembled monolayer (SAM) on the surface of the Au (111) Schottky contacts of the n-GaAs substrate using immersion method. The adsorption behaviors between SAM and Au (111) with different terminal (functional) groups, carbon numbers (CN), immersion times (tim), and alkanedithiol concentrations were characterized by cyclic voltammetry (CV) measurement. The interaction between NOx molecules and SAM was determined by an ultraviolet/visible (UV-Vis) spectrophotometer. The NOx sensing performance of the studied device under proper conditions was investigated at different temperatures and NOx gas concentrations. Experimentally, at 25℃, good sensing responses of 49.6 and 35.5 in 100 ppm NO2 and NO ambiences were obtained, respectively. Furthermore, similar sensing properties of the studied device were found in air and in N2 ambience. Therefore, the studied device can be considered a promising candidate for NOx sensing applications.
关键词： Alkanedithiol,Nitrogen oxides,Gas sensors,Schottky diode,GaAs,Self-assembled monolayers (SAM)
更新于2025-09-12 10:27:22
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Self-assembled interface monolayers for organic and hybrid electronics
摘要： The state of the art in the field of self-assembled organic interface monolayers widely used in organic and hybrid electronics is analyzed and the results obtained are summarized. Recent advances in full and local substrate modification using interface layers are considered in detail. Examples of the most successful applications of interface monolayers as monolayer dielectrics, modifiers of the work function and adhesion promoters are given. The advantages of utilizing interface monolayers at semiconductor/dielectric interfaces and for modifying the semiconductor surface are demonstrated. Specific features of formation of nanostructured surfaces including those used in biosensoric applications are outlined.
关键词： adhesion promoters,work function modifiers,biosensors,organic electronics,interface layers,hybrid electronics,dielectrics,self-assembled monolayers
更新于2025-09-12 10:27:22
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The effect of phenylboronic acid-based self-assembled monolayers on theperformance of organic field-effect transistors (OFETs)
摘要： The dielectric/semiconductor interface is one of the most important components strongly affecting the performance of organic field-effect transistors (OFETs). To improve OFET parameters, we applied a series of phenylboronic acid derivatives as self-assembly molecules between dielectric and organic semiconductor layers. Device performance parameters, especially threshold voltage, current on/off ratio, and subthreshold slope, were improved. To elucidate the mechanism, dielectric/semiconductor interfaces were analyzed using atomic force microscope and contact angle techniques.
关键词： self-assembled monolayer,Interface modification,organic field-effect transistor
更新于2025-09-12 10:27:22
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Self-Assembled Monolayers with Distributed Dipole Moments Originating from Bipyrimidine Units
摘要： The concept of distributed dipoles in monomolecular self-assembly on solid substrates was tested for the example of thiolate self-assembled monolayers (SAMs) on Au(111) containing dipolar 2,5?-bipyrimidine units. These were attached to a thiol anchoring group either directly or via a phenylene-methylene spacer, with the spacer decoupling the dipolar moiety from the substrate and promoting layer formation. As expected, the SAMs containing spacer groups exhibited a higher quality, including a higher packing density and nearly upright molecular orientation. The electrostatic effects of the dipolar bipyrimidine moieties were tested through C 1s and N 1s photoemission spectra, where electrostatic core-level shifts impact the shapes of the spectra. Additionally, changing the orientation of the dipoles allows a variation of the work function over a range of ~1.35 eV. The experiments were complemented by density-functional theory calculations. The work function tuning range was reasonably high, but smaller than expected considering that for SAMs with a single embedded pyrimidine group per molecule work-function changes already amounted to ~1.0 eV. This behavior is rooted in an asymmetry of the studied SAMs: For dipoles pointing away from the substrate, the expected doubling of the work function change between monopyrimidine and bipyrimidine SAMs essentially occurs. Conversely, for the downward-oriented pyrimidine dipoles, the second polar ring has hardly any effect. Consistent observations were made for the core-level shifts. We discuss several factors, which are potentially responsible for this asymmetry, like disorder, depolarization, or Fermi-level pinning. Of these, the most likely explanation is the adsorption of airborne contaminants interacting with the nitrogen atoms in the immediate vicinity of the outer surface, which are present only in films with downward oriented dipoles. In spite of these complications, some of the introduced distributed dipole SAMs serve as important model systems for understanding electrostatic effects at interfaces. They are also of interest for controlling carrier-injection barriers in organic (opto)electronic devices.
关键词： Bipyrimidine Units,Distributed Dipole Moments,Self-Assembled Monolayers,Organic (Opto)electronic Devices,Work Function Tuning
更新于2025-09-12 10:27:22