- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Spectral Interrogation based SPR Sensor for Blood Glucose Detection with Improved Sensitivity and Stability
摘要： A sensor chip for specific detection of blood glucose was developed. The sensor utilized a surface-plasmon-resonance (SPR) setup on a prism based Kretschmann configuration utilizing spectral interrogation scheme. Self-assembled monolayers (SAMs) based preparation provided the chip stability due to covalent bonds and hence it can be reused for multiple times. Such a scheme can be advantageous in continuous monitoring of blood glucose, without changing the chip. Control experiments were performed without molecular recognition layer to confirm the performance of the sensor. Furthermore, the measurements were performed on blood serums and compared with that of a conventional glucometer. The present sensor has the advantages of improved sensitivity (0.14 nm/(mg/dl)) and stable response for 3 months, which are better compared to existing reports.
关键词： Blood glucose,Self assembled monolayers,Surface plasmon resonance,Biosensor
更新于2025-09-19 17:15:36
-
Study of the Molecular Bending in Azobenzene Self-Assembled Monolayers Observed by Tip-Enhanced Raman Spectroscopy in Scanning Tunneling Mode
摘要： Tip-enhanced Raman Spectroscopy (TERS) is capable of amplifying the extremely weak Raman response of azobenzene self-assembled monolayers (SAMs), thus allowing for the chemical characterization of the sample surface at the nanoscale. Recently, we introduced a physical model describing the TERS intensity of azobenzene SAMs probed in a scanning tunneling mode configuration (STM-TERS), that takes into account the molecular bending induced by the high electric field inside the tunneling junction. The model predicts quite well the experimental variation in the TERS intensity of a hexil azobenzene SAM (AzoC6) on gold polycrystalline film (111) with changing the electric field in the gap between the tip and the substrate. Nevertheless, a disagreement between the model and the experiment has been observed while studying, in the same conditions, the TERS intensity of undecyl azobenzene (AzoC11) SAM formed by molecules featuring an alkyl chain nearly two times longer with respect to the previous case. In this work we extend the molecular bending model through considering an additional bending mechanism due to the mechanical interaction between the tip and the SAM, occurring when the tip-to-sample distance is shorter than the molecular length. The extended model is able to describe well the TERS intensity behavior with changing either the bias voltage or the tip-to-sample distance for both AzoC6 and AzoC11. Eventually, we determine quantitatively the difference in elastic properties of the two molecules physically accounting for the difference in the TERS intensity behavior of the two SAMs.
关键词： STM-TERS,self-assembled monolayers,SAMs,Tip-enhanced Raman Spectroscopy,TERS,molecular bending,azobenzene
更新于2025-09-19 17:13:59
-
A Self-Assembled Chromophore/Catalyst Bilayer for Water Oxidation in a Dye-Sensitized Photoelectrosynthesis Cell
摘要： A new approach is described here for the preparation of water oxidation photoanodes in a Dye-Sensitized Photoelectrosynthesis Cell (DSPEC) for water splitting. It is based on a chromophore (C) - catalyst (Cat) assembly prepared by a self-assembled bilayer (SAB) on a mesoporous SnO2/TiO2 core/shell electrode, FTO| SnO2/TiO2|-C-Cat. A key feature in the resulting assembly is the in-situ “synthesis” by utilization of non-covalent interactions between long alkyl substituents of the chromophore and catalyst components. The photoanode carries out photoelectrochemical water oxidation for more than 3 hours with ~ 86% faradaic efficiency for oxygen generation. At pH 7 under 1 sun illumination, the photoanode reaches a photocurrent density of ~2.2 mA/cm2 with an incident photon to current efficiency (IPCE) of 29% at 450 nm. With an injection yield of only ~ 42%, the efficiency of the cell, excluding the losses at the core/shell interface, is a remarkable 67 %.
关键词： water oxidation,photoelectrochemical,chromophore-catalyst assembly,dye-sensitized photoelectrosynthesis cell,self-assembled bilayer
更新于2025-09-19 17:13:59
-
[IEEE 2019 IEEE Pulsed Power & Plasma Science (PPPS) - Orlando, FL, USA (2019.6.23-2019.6.29)] 2019 IEEE Pulsed Power & Plasma Science (PPPS) - Auto-collimation and monitoring of laser beam in high power electron-pumped KrF laser facility
摘要： Record low values in this material system of threshold current density, particularly at elevated temperature, are presented for InP quantum dot lasers. Lasers with Ga0 .5 8 In0 .4 2 P in the dot upper con?ning layer have the lowest threshold current densities, 138 A·cm?2 at 300 K, and 235 A·cm?2 at 350 K (77 °C) (2-mm lasers, uncoated facets). Gain-current density data suggests laser performance with an upper con?ning layer of Gax In1 ?xP with x = 0.54, 0.56 or 0.58 would be similar if not for the very low internal optical mode loss, αi of samples with x = 0.56 and 0.58. Gain measurements at ?xed inversion level suggest that increasing x content in Gax In1 ?xP increases gain at ?xed inversion level but samples with x = 0.54 also exhibit reduced recombination current density. The increasing recombination current density at elevated temperature due to thermal carrier spreading is signi?cantly reduced in samples with x = 0.56 and x = 0.58 but measurements at common operating points attribute this largely to the reduced αi for these samples and given the same αI , samples with x = 0.54, 0.56 and 0.58 would all bene?t from reduced effects due to thermal carrier spreading compared to x = 0.52.
关键词： Quantum dot devices,InP self-assembled quantum dots,semiconductor laser,short wavelength lasers,threshold current density,temperature sensitivity
更新于2025-09-19 17:13:59
-
Modulating the luminance of organic light-emitting diodes via optical stimulation of a photochromic molecular monolayer at transparent oxide electrode
摘要： Self-assembled monolayers (SAMs) deposited on bottom electrodes are commonly used to tune charge carrier injection or blocking in optoelectronic devices. Beside the enhancement of device performance, the fabrication of multifunctional devices in which the output can be modulated by multiple external stimuli remains a challenging target. In this work, we report the functionalization of an indium tin oxide (ITO) electrode with a SAM of a diarylethene derivative designed for optically control the electronic properties. Following the demonstration of dense SAM formation and its photochromic activity, as a proof-of-principle, an organic light-emitting diode (OLED) embedding the light-responsive SAM-covered electrode was fabricated and characterized. Optically addressing the two-terminal device by irradiation with ultraviolet light doubles the electroluminescence. The original value can be restored reversibly by irradiation with visible light. This expanded functionality is based on the photoinduced modulation of the electronic structure of the diarylethene isomers, which impact the charge carriers’ confinement within the emissive layer. This approach could be successfully exploited in the field of opto-communication technology, for example to fabricate opto-electronic logic circuits.
关键词： photochromic,optoelectronic devices,diarylethene,Self-assembled monolayers,organic light-emitting diodes
更新于2025-09-19 17:13:59
-
Self‐Assembled Room Temperature Multiferroic BiFeO <sub/>3</sub> ‐LiFe <sub/>5</sub> O <sub/>8</sub> Nanocomposites
摘要： Multiferroic materials have driven significant research interest due to their promising technological potential. Developing new room-temperature multiferroics and understanding their fundamental properties are important to reveal unanticipated physical phenomena and potential applications. Here, a new room temperature multiferroic nanocomposite comprised of an ordered ferrimagnetic spinel α-LiFe5O8 (LFO) and a ferroelectric perovskite BiFeO3 (BFO) is presented. It is observed that lithium (Li)-doping in BFO favors the formation of LFO spinel as a secondary phase during the synthesis of LixBi1?xFeO3 ceramics. Multimodal functional and chemical imaging methods are used to map the relationship between doping-induced phase separation and local ferroic properties in both the BFO-LFO composite ceramics and self-assembled nanocomposite thin films. The energetics of phase separation in Li doped BFO and the formation of BFO-LFO composites are supported by first principles calculations. These findings shed light on Li’s role in the formation of a functionally important room temperature multiferroic and open a new approach in the synthesis of light element doped nanocomposites for future energy, sensing, and memory applications.
关键词： light element doping,thin film nanostructures,multiferroics,nanoferroic properties,scanning probe microscopy,self-assembled nanocomposites
更新于2025-09-19 17:13:59
-
Self-Assembled Amphiphilic Molecules for Highly Efficient Photocatalytic Hydrogen Evolution From Water
摘要： Self-assembled molecules for outstanding hydrogen evolution rate and durability should promise practical water splitting due to the versatile visible light absorption, low production cost and ease of control. Here, we adapted an amphiphilic molecule as a building block for efficient small molecule based self-assembled photocatalyst for hydrogen evolution from water. The self-assembled molecules with platinum co-catalyst showed outstanding performance (turnover number ~ 27,000) virtually comparable to the state-of-the-art metal oxide based photocatalysts with catalytic activity extending over days. Transient absorption studies in combination with quantum chemical calculations revealed that elaborate excited state engineering of the molecules resulted in such high performance of hydrogen evolution from water. This study shows that the self-assembled amphiphilic molecules could pave the way to more economical and reproducible production of hydrogen from water.
关键词： Platinum co-catalyst,Amphiphilic molecule,Photocatalytic hydrogen evolution,Excited state engineering,Self-assembled molecules
更新于2025-09-19 17:13:59
-
[IEEE 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Guangzhou, China (2019.5.19-2019.5.22)] 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - A Circularly Polarized Waveguide Slot Antenna for Random Array Application
摘要： Record low values in this material system of threshold current density, particularly at elevated temperature, are presented for InP quantum dot lasers. Lasers with Ga0.58In0.42P in the dot upper con?ning layer have the lowest threshold current densities, 138 A·cm?2 at 300 K, and 235 A·cm?2 at 350 K (77 °C) (2-mm lasers, uncoated facets). Gain-current density data suggests laser performance with an upper con?ning layer of GaxIn1?xP with x = 0.54, 0.56 or 0.58 would be similar if not for the very low internal optical mode loss, αi of samples with x = 0.56 and 0.58. Gain measurements at ?xed inversion level suggest that increasing x content in GaxIn1?xP increases gain at ?xed inversion level but samples with x = 0.54 also exhibit reduced recombination current density. The increasing recombination current density at elevated temperature due to thermal carrier spreading is signi?cantly reduced in samples with x = 0.56 and x = 0.58 but measurements at common operating points attribute this largely to the reduced αi for these samples and given the same αI, samples with x = 0.54, 0.56 and 0.58 would all bene?t from reduced effects due to thermal carrier spreading compared to x = 0.52.
关键词： Quantum dot devices,InP self-assembled quantum dots,semiconductor laser,short wavelength lasers,threshold current density,temperature sensitivity
更新于2025-09-19 17:13:59
-
Self-Assembled Monolayers with Embedded Dipole Moments for Work Function Engineering of Oxide Substrates
摘要： Self-assembled monolayers (SAMs) are frequently used for work function (WF) engineering of different materials. For this, typically dipolar groups are attached to the molecule terminus at the SAM?ambient interface, which also influences its chemistry. WF engineering and interface chemistry can, however, be decoupled from one another using embedded dipolar groups, as has been demonstrated before for thiolate SAMs on metals. Herein, we extend this concept to oxide substrates. For this, a series of biphenyl-based molecules with a phosphonic acid (PA) anchoring group was synthesized, with one of the nonpolar phenyl units exchanged for a polar pyrimidine moiety, the dipole moment of which is oriented either toward (“down”) or away (“up”) to/from the PA group and, consequently, to/from the substrate. SAMs of these molecules formed on indium tin oxide (ITO), a frequently used and application-relevant oxide substrate, feature a uniform molecular configuration, dense molecular packing, and an upright molecular orientation. These SAMs exhibit pronounced electrostatic effects associated with the embedded dipolar groups, viz. shifts of the characteristic peaks in the C 1s X-ray photoelectron spectra and WF variations. The latter values were found to be 3.9, 4.85, and 4.4 eV for the up, down, and nonpolar reference SAM-engineered ITO, respectively. Consequently, these SAMs can serve as a powerful tool to monitor WF engineering effects in a variety of device assembles, decoupling these effects from the interface chemistry. The comparably low WF value for the up SAM is particularly important since it extends a rather limited variety of SAMs capable of lowering the WF of ITO.
关键词： Phosphonic acid,Self-assembled monolayers,Work function engineering,Embedded dipolar groups,Indium tin oxide,Oxide substrates
更新于2025-09-19 17:13:59
-
An electro-tunable Fabry–Perot interferometer based on dual mirror-on-mirror nanoplasmonic metamaterials
摘要： Mirror-on-mirror nanoplasmonic metamaterials, formed on the basis of voltage-controlled reversible self-assembly of sub-wavelength-sized metallic nanoparticles (NPs) on thin metallic film electrodes, are promising candidates for novel electro-tunable optical devices. Here, we present a new design of electro-tunable Fabry–Perot interferometers (FPIs) in which two parallel mirrors – each composed of a monolayer of NPs self-assembled on a thin metallic electrode – form an optical cavity, which is filled with an aqueous solution. The reflectivity of the cavity mirrors can be electrically adjusted, simultaneously or separately, via a small variation of the electrode potentials, which would alter the inter-NP separation in the monolayers. To investigate optical transmittance from the proposed FPI device, we develop a nine-layer-stack theoretical model, based on our effective medium theory and multi-layer Fresnel reflection scheme, which produces excellent match when verified against full-wave simulations. We show that strong plasmonic coupling among silver NPs forming a monolayer on a thin silver-film substrate makes reflectivity of each cavity mirror highly sensitive to the inter-NP separation. Such a design allows the continuous tuning of the multiple narrow and intense transmission peaks emerging from an FPI cavity via electro-tuning the inter-NP separation in situ – reaping the benefits from both inexpensive bottom-up fabrication and energy-efficient tuning.
关键词： electro-tunable optical devices,voltage-controlled reversible self-assembly,self-assembled plasmonic nanoparticles,Fabry–Perot interferometers
更新于2025-09-16 10:30:52