Self-assembled monolayers of octadecanethiol (ODT) on gold have been studied by electrochemical impedance spectroscopy (EIS). The fractional coverage has been examined as a function of immersion time of Au in ODT depo...Self-assembled monolayers of octadecanethiol (ODT) on gold have been studied by electrochemical impedance spectroscopy (EIS). The fractional coverage has been examined as a function of immersion time of Au in ODT deposition solution. The fractional coverage exhibits two distinct adsorption steps: an initial rapid step followed by a slow one. The fractional coverage of ODT monolayer increases sharply from zero to more than 99% of its maximum within the first minute. However. it takes a day for the fractional coverage to approach its final value.展开更多
NiO_(x)as a hole transport material for inverted perovskite solar cells has received great attention owing to its high transparency,low fabrication temperature,and superior stability.However,the mismatched energy leve...NiO_(x)as a hole transport material for inverted perovskite solar cells has received great attention owing to its high transparency,low fabrication temperature,and superior stability.However,the mismatched energy levels and possible redox reactions at the NiO_(x)/perovskite interface severely limit the performance of NiO_(x) based inverted perovskite solar cells.Herein,we introduce a p-type self-assembled monolayer between NiO_(x)and perovskite layers to modify the interface and block the undesirable redox reaction between perovskite and NiO_(x)The selfassembled monolayer molecules all contain phosphoric acid function groups,which can be anchored onto the NiOr surface and passivate the surface defect.Moreover,the introduction of self-assembled monolayers can regulate the energy level structure of NiO_(x),reduce the interfacial band energy offset,and hence promote the hole transport from perovskite to NiO_(x)layer.Consequently,the device performance is significantly enhanced in terms of both power conversion efficiency and stability.展开更多
The hydroxyl-terminated self-assembled monolayer(OH-SAM),as a surface resistant to protein adsorption,exhibits substantial potential in applications such as ship navigation and medical implants,and the appropriate str...The hydroxyl-terminated self-assembled monolayer(OH-SAM),as a surface resistant to protein adsorption,exhibits substantial potential in applications such as ship navigation and medical implants,and the appropriate strategies for designing anti-fouling surfaces are crucial.Here,we employ molecular dynamics simulations and alchemical free energy calculations to systematically analyze the factors influencing resistance to protein adsorption on the SAMs terminated with single or double OH groups at three packing densities(∑=2.0 nm^(-2),4.5 nm^(-2),and 6.5 nm^(-2)),respectively.For the first time,we observed that the compactness and order of interfacial water enhance its physical barrier effect,subsequently enhancing the resistance of SAM to protein adsorption.Notably,the spatial hindrance effect of SAM leads to the embedding of protein into SAM,resulting in a lack of resistance of SAM towards protein.Furthermore,the number of hydroxyl groups per unit area of double OH-terminated SAM at ∑=6.5 nm^(-2) is approximately 2 to 3 times that of single OH-terminated SAM at ∑=6.5 nm^(-2) and 4.5 nm^(-2),consequently yielding a weaker resistance of double OH-terminated SAM towards protein.Meanwhile,due to the structure of SAM itself,i.e.,the formation of a nearly perfect ice-like hydrogen bond structure,the SAM exhibits the weakest resistance towards protein.This study will complement and improve the mechanism of OH-SAM resistance to protein adsorption,especially the traditional barrier effect of interfacial water.展开更多
Dielectric properties of dithiol self-assemble monolayers （SAMs） under ac electric field were presented, Using a Hg-SAM/SAM-Ⅱg junction, the ac impedances of dithiol SAMs were measured using a sinusoidal perturbati...Dielectric properties of dithiol self-assemble monolayers （SAMs） under ac electric field were presented, Using a Hg-SAM/SAM-Ⅱg junction, the ac impedances of dithiol SAMs were measured using a sinusoidal perturbation of 30 mV （peak to-peak） with the frequency ranging from 1 Hz to 1 MHz at zero bias. The contributions from dithiol SAMs and solvent interlayers were separated due to their different behaviors at ac impedance. The peak position in the loss spectra （the plot; of tgδ vs. frequency） moves to low frequcney with the incrcase of chain length of dithiols. Using a correlation of peak position with the chain length, the active energies of 23-39 meV for dithiol SAMs of C6-C10 under an ac electric field were derived,展开更多
Numerous reports have suggested that the performance of organic optoelectronic devices based on organicfieldeffect transistors(OFETs)is largely dependent on their interfaces.Self-assembled monolayers(SAMs)have been co...Numerous reports have suggested that the performance of organic optoelectronic devices based on organicfieldeffect transistors(OFETs)is largely dependent on their interfaces.Self-assembled monolayers(SAMs)have been commonly used to engineer the interfaces of high-performance devices,particularly due to their well-defined structures and simple operation process through simple chemical adsorption growth.In this review,the structures of OFETs and SAM-modified OFETs are described,while different SAMs have been characterized.Furthermore,recent advances in the interface engineering of OFETs are described,the applicability of SAMs in functional devices of OFETs is reviewed,and existing problems and future developments in thisfield have been identified.展开更多
Self-assembled monolayers(SAMs)have recently emerged as excellent hole transport materials in inverted perovskite solar cells(PSCs)owing to their ability to minimize parasitic absorption,regulate energy level alignmen...Self-assembled monolayers(SAMs)have recently emerged as excellent hole transport materials in inverted perovskite solar cells(PSCs)owing to their ability to minimize parasitic absorption,regulate energy level alignment,and passivate perovskite defects.Herein,we design and synthesize a novel dimethyl acridinebased SAM,[2-(9,10-dihydro-9,9-dimethylacridine-10-yl)ethyl]phosphonic acid(2PADmA),and employ it as a hole-transporting layer in inverted PSCs.Experimental results show that the 2PADmA SAM can modulate perovskite crystallization,facilitate carrier transport,passivate perovskite defects,and reduce nonradiative recombination.Consequently,the 2PADmA-based device achieves an enhanced power conversion efficiency(PCE)of 24.01%and an improved fill factor(FF)of 83.92%compared to the commonly reported[2-(9H-carbazol-9-yl)ethyl]phosphonic acid(2PACz)-based control device with a PCE of 22.32%and FF of 78.42%,while both devices exhibit comparable open-circuit voltage and short-circuit current density.In addition,2PADmA-based devices exhibit outstanding dark storage and thermal stabilities,retaining approximately~98%and 87%of their initial PCEs after 1080 h of dark storage and 400 h of heating at 85°C,respectively,both considerably superior to the control device.展开更多
We investigate tunneling electron induced luminescence from isolated single porphyrin molecules that are decoupled by striped-phase self-assembled monolayer of octanethiol from the underneath Au（111） substrate. Intr...We investigate tunneling electron induced luminescence from isolated single porphyrin molecules that are decoupled by striped-phase self-assembled monolayer of octanethiol from the underneath Au（111） substrate. Intrinsic single-molecule electroluminescence has been realized by such decoupling at both bias polarities. The photon emission intensity acquired from the molecular lobe is found stronger than that from the molecular center. These re- sults provide useful information on the understanding of electroluminescent behavior and mechanism in molecular tunnel junctions.展开更多
The electrochemical behavior of trifluoperazine at decanethiol self-assembledmonolayer (SAM) modified gold electrodes (i. e. C_(10) H_(21) SH/Au) has been studied,Trifluoperazine can effectively accumulate on C_(10) H...The electrochemical behavior of trifluoperazine at decanethiol self-assembledmonolayer (SAM) modified gold electrodes (i. e. C_(10) H_(21) SH/Au) has been studied,Trifluoperazine can effectively accumulate on C_(10) H_(21) SH/Au electrodes and generate asensitive anodic peak at about 0.63 V (vs. SCE) in 0.05 mol/L pH 9.4 Na_2 B_4 O_7 buffer solution.Under the selected conditions, the anodic peak current was linear to trifluoperazine concentrationin the range of 5.0 X 10^(-7)-3.O X 10^(-3) mol/Lwith correlation coefficient of 0.997, thedetection limit was 3.0 X 10^(-5) mol/L. This method was applied to the determination oftrifluoperazine in drug samples and the recovery was 97.3%-104.0% It was found that sodium dodecylsulfate (SDS) could make the anodic peak current increase. In the presence of SDS, the peak at about0.63 V turned into two peaks, resulting from the change of the electrochemical mechanism.展开更多
Self-assembly of octadecyl mercaptan on gold was investigated by cyclic voltammetry(CV) and electrochemical impedance spectroscopy (EIS). Results of CV experiments show thatthere are no structUral defects exposed dire...Self-assembly of octadecyl mercaptan on gold was investigated by cyclic voltammetry(CV) and electrochemical impedance spectroscopy (EIS). Results of CV experiments show thatthere are no structUral defects exposed directly to the redox couple in solution, but EISexperiments indicate that collapsed sites exist in the monolayer. A method to estimate the degree ofdisorder in the Au/thiol monolayer surface is proposed by using admittance plane plot.展开更多
The carbon nanotube (fundamentally Single- walled carbon nanotube, SWCNT) based on 1-Amino-undecanethiol (AUT) were extremely controlled (nano-level) organizing a vertical self-assembled monolayer (SAM) on gold single...The carbon nanotube (fundamentally Single- walled carbon nanotube, SWCNT) based on 1-Amino-undecanethiol (AUT) were extremely controlled (nano-level) organizing a vertical self-assembled monolayer (SAM) on gold single crystal surfaces. The produced nano-surfaces were explored particularly by Fourier Transform Infra-red Spectroscopy (FT-IR), Cyclic Voltammetry (CV), Raman spectroscopy, Electrochemi- cal quartz crystal microbalance (EQCM), and Atomic force microscopy (AFM) techniques. The SWCNTs were initially cut (chemically) into short pipes and thiol-derivatized at the open ends. The vertical aggregation of SWCNT-AUTs on chemically refined Au(111) substrates was made-up by their spontaneous chemical bonding among carboxyl derivatized SWCNT-COOH and AUT SAM on Au(111), via peptide bonds, or directly by synthesized SWCNT-AUT composites. Raman spectroscopy and AFM surface images obviously disclosed that the SWCNT- AUT (dia. 20~40 nm) has been vertically categorized d on gold (111) substrates, shaping a SAM with a perpendicular direction.展开更多
A mixed self-assembled monolayers （SAMs） of thioctic acid （T-COOH） and thioctic acid amide （T-NH2） were used to immobilize tyrosinase for fabricating biosensor. The results showed that the mixed SAMs prepared fr...A mixed self-assembled monolayers （SAMs） of thioctic acid （T-COOH） and thioctic acid amide （T-NH2） were used to immobilize tyrosinase for fabricating biosensor. The results showed that the mixed SAMs prepared from solution at the ratio of 1：4 provided an excellent microenvironment for enzymatic reaction between tyrosinase and substrate. The biosensor exhibited a fast response and high sensitivity for sensing substrate.展开更多
A thioester-functionalized triphenylamine hole-transporting molecule （TPD-SAc） was synthesized and self-assembled to form a monolayer on an ultra-thin Au film supported on indium-tin oxide glass. The modified surfac...A thioester-functionalized triphenylamine hole-transporting molecule （TPD-SAc） was synthesized and self-assembled to form a monolayer on an ultra-thin Au film supported on indium-tin oxide glass. The modified surface was characterized by aqueous contact angle, ellipsometer, atomic force microscopy, X-ray photoelectron spectroscopy, and ultraviolet pho- toelectron spectrometer to substantiate the formation of compact and pinhole-free monolayers. The modified organic light emitting diode device [indium-tin oxide/Au （5 nm）/self-assembled monolayers （SAM）/TPD （50 nm）/Alq3 （40 nm）/TPBI （15 nm）/LiF （1 nm）/A1 （100 nm）] showed a luminance of 7303.90 cd/m^2 and a current efficiency of 8.49 cd/A with 1.78 and 2.29-fold increase, respectively, compared to the control device without SAM. The improvements were attributed to the enhanced compatibility of the organic-inorganic interface, matched energy level by introduction of an energy mediating step and superior hole-injection property of SAM molecules.展开更多
Self assembled monolayers (SAMs) of to-mercapto methoxy poly(ethylene glycol)(MPEG) on gold electrode were used as a means to detect dopamine. Dopamine (DA) had good response at the MPEG film electrode and ascorbic ac...Self assembled monolayers (SAMs) of to-mercapto methoxy poly(ethylene glycol)(MPEG) on gold electrode were used as a means to detect dopamine. Dopamine (DA) had good response at the MPEG film electrode and ascorbic acid (AA) was repelled from the SAMs. TheMPEG film is a biocompatible film, there was no adsorption of biosample and no inactivation atelectrode surface when it was used to detect DA in biosamples.展开更多
The electrochemical quartz crystal microbalance (EQCM) is used to investigate the characteristics of the thiolated self-assembled monolayer(SAM) on gold surface.A 5MHz QCM element serves as both the mass-sensitive sen...The electrochemical quartz crystal microbalance (EQCM) is used to investigate the characteristics of the thiolated self-assembled monolayer(SAM) on gold surface.A 5MHz QCM element serves as both the mass-sensitive sensor and the working electrode of the electrochemical system.The 6-mecapto-1-hexanol and and the 16-mer oligonucleotide with a mercaptohexyl group at the 5'-phosphate end are utilized to form the SAM on the gold electrode.The frequency response of the QCM during cyclic voltammetry (CV) scanning and cbronoamperometry are recorded together with the electrochemical current.The experimental results indicates that the frequency response is more sensitive to the surface coverage.Therefore,the response of the EQCM reveals more details of the SAM on gold electrode.It is especially useful for analysing the immobilization quality,such as probe orientation and coverage,of the SAM.展开更多
SrTiO3 thin film was successfully prepared on the functionalized organic self-assembled monolayers（SAMs） by the Liquid Phase Deposition（LPD） method.The as-prepared samples were characterized by X-ray diffraction（...SrTiO3 thin film was successfully prepared on the functionalized organic self-assembled monolayers（SAMs） by the Liquid Phase Deposition（LPD） method.The as-prepared samples were characterized by X-ray diffraction（XRD）,atomic force microscope（AFM）,scanning electron microscopy（SEM） and metallographic microscope.Measurement of contact angle showed that the hydrophobe substrate was changed into hydrophile by UV irradiation.AFM photographs of octadecyl-trichloro-silane self-assembled monolayer（OTS-SAM） surface approved that UV irradiation did change the morphology of OTS monolayer and provided evidence for the conversion of hydrophilic characteristic.Photographs of Metallographic Microscope showed that OTS-SAM had an active effect on the deposition of SrTiO3 thin film.XRD and SEM indicated that the thin film was of pure cubic phase SrTiO3 and composed of nanosized grains with a size in the range of 100-500 nm.The formation mechanism of the SrTiO3 film was proposed.展开更多
Lipoic acid (LA) has received great attention in the area of gold surface functionalization. In this study, LA was employed as a linker for the attachment of antibody to the gold surface of surface plasmon resonance (...Lipoic acid (LA) has received great attention in the area of gold surface functionalization. In this study, LA was employed as a linker for the attachment of antibody to the gold surface of surface plasmon resonance (SPR) chip. By using this chip in a homemade SPR immunosensor, low molecular weight compound 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) can be detected at a low level of 0.01 ng/mL. There is a good linear relationship(R2 =0.943 1) between the results of SPR biosensor and enzyme-linked immunosorbent assay(ELISA).展开更多
A newly synthesized reagent 2-amino-5-mercapto-[1, 3, 4]triazole (MATZ) has been usedto fabricate self-assembled monolayers (SAMs) on gold electrode for the first time. The SAMselectrode was characterized by electroch...A newly synthesized reagent 2-amino-5-mercapto-[1, 3, 4]triazole (MATZ) has been usedto fabricate self-assembled monolayers (SAMs) on gold electrode for the first time. The SAMselectrode was characterized by electrochemical methods and scanning electronic microscopy (SEM),the SAMs electrode can be used to determinate dopamine (DA) and uric acid (UA) simultaneouslywith a detection limit of 8×10-7 mol/L for DA and 1×10-6 mol/L for UA respectively. The SAMscan also be used to detect the contents of DA and UA in synthetic urine sample with satisfactoryresults.展开更多
The orientation of the biological molecule immobi-lized on a solid surface has been critical in devel-opment of various applications. In this study, ori-entation of antibody was retained by protecting the antigen-bind...The orientation of the biological molecule immobi-lized on a solid surface has been critical in devel-opment of various applications. In this study, ori-entation of antibody was retained by protecting the antigen-binding site of the antibody prior to immo-bilization to -functionalized mixed self-assembled monolayer (SAM) of 12-mercaptododecanoic acid and 1-heptanethiol. More importantly, the number of immobilization bonds formed between each an-tigen-binding site protected antibody molecule and the solid surface was controlled by optimizing the mole fraction of the activated carboxyl group of the linker molecules in the mixed SAM. The amount of antibody used in this study was approximately equivalent to the amount for one monolayer surface coverage. The resulting activity of protected immo-bilized antibody was about 10 fold higher than that of random immobilized展开更多
This work details a study based on HfS_(2 )transistors utilizing an n-octadecylphosphonic acid-based self-assembled monolayer(SAM)as the gate dielectric.The fabrication of the SAM-based two-dimensional(2D)material tra...This work details a study based on HfS_(2 )transistors utilizing an n-octadecylphosphonic acid-based self-assembled monolayer(SAM)as the gate dielectric.The fabrication of the SAM-based two-dimensional(2D)material transistor is simple and can be used to improve the quality of the interface of air-sensitive 2D materials.In comparison to HfS_(2) transistors utilizing a conventional Al_2O_(3) gate insulator by atomic layer deposition,HfS_(2) transistors utilizing an SAM as the gate dielectric can reduce the operation region from 4 V to 2 V,enhance the field-effect mobility from 0.03 cm^2/Vs to 0.75 cm^2/Vs,improve the sub-threshold swing from 404 m V/dec to 156 m V/dec,and optimize the hysteresis to 0.03 V,thus demonstrating improved quality of the semiconductor/insulator interface.展开更多
基金the Natural Science Foundation of Hebei Province.
文摘Self-assembled monolayers of octadecanethiol (ODT) on gold have been studied by electrochemical impedance spectroscopy (EIS). The fractional coverage has been examined as a function of immersion time of Au in ODT deposition solution. The fractional coverage exhibits two distinct adsorption steps: an initial rapid step followed by a slow one. The fractional coverage of ODT monolayer increases sharply from zero to more than 99% of its maximum within the first minute. However. it takes a day for the fractional coverage to approach its final value.
文摘NiO_(x)as a hole transport material for inverted perovskite solar cells has received great attention owing to its high transparency,low fabrication temperature,and superior stability.However,the mismatched energy levels and possible redox reactions at the NiO_(x)/perovskite interface severely limit the performance of NiO_(x) based inverted perovskite solar cells.Herein,we introduce a p-type self-assembled monolayer between NiO_(x)and perovskite layers to modify the interface and block the undesirable redox reaction between perovskite and NiO_(x)The selfassembled monolayer molecules all contain phosphoric acid function groups,which can be anchored onto the NiOr surface and passivate the surface defect.Moreover,the introduction of self-assembled monolayers can regulate the energy level structure of NiO_(x),reduce the interfacial band energy offset,and hence promote the hole transport from perovskite to NiO_(x)layer.Consequently,the device performance is significantly enhanced in terms of both power conversion efficiency and stability.
基金Project supported by the National Natural Science Foundation of China (Grants No. 12075201)the Science and Technology Planning Project of Jiangsu Province, China (Grant No. BK20201428)+1 种基金the Postgraduate Research & Practice Innovation Program of Jiangsu Province, China (Grant No. KYCX21 3193)the Special Program for Applied Research on Supercomputation of the NSFC–Guangdong Joint Fund (the second phase)。
文摘The hydroxyl-terminated self-assembled monolayer(OH-SAM),as a surface resistant to protein adsorption,exhibits substantial potential in applications such as ship navigation and medical implants,and the appropriate strategies for designing anti-fouling surfaces are crucial.Here,we employ molecular dynamics simulations and alchemical free energy calculations to systematically analyze the factors influencing resistance to protein adsorption on the SAMs terminated with single or double OH groups at three packing densities(∑=2.0 nm^(-2),4.5 nm^(-2),and 6.5 nm^(-2)),respectively.For the first time,we observed that the compactness and order of interfacial water enhance its physical barrier effect,subsequently enhancing the resistance of SAM to protein adsorption.Notably,the spatial hindrance effect of SAM leads to the embedding of protein into SAM,resulting in a lack of resistance of SAM towards protein.Furthermore,the number of hydroxyl groups per unit area of double OH-terminated SAM at ∑=6.5 nm^(-2) is approximately 2 to 3 times that of single OH-terminated SAM at ∑=6.5 nm^(-2) and 4.5 nm^(-2),consequently yielding a weaker resistance of double OH-terminated SAM towards protein.Meanwhile,due to the structure of SAM itself,i.e.,the formation of a nearly perfect ice-like hydrogen bond structure,the SAM exhibits the weakest resistance towards protein.This study will complement and improve the mechanism of OH-SAM resistance to protein adsorption,especially the traditional barrier effect of interfacial water.
文摘Dielectric properties of dithiol self-assemble monolayers （SAMs） under ac electric field were presented, Using a Hg-SAM/SAM-Ⅱg junction, the ac impedances of dithiol SAMs were measured using a sinusoidal perturbation of 30 mV （peak to-peak） with the frequency ranging from 1 Hz to 1 MHz at zero bias. The contributions from dithiol SAMs and solvent interlayers were separated due to their different behaviors at ac impedance. The peak position in the loss spectra （the plot; of tgδ vs. frequency） moves to low frequcney with the incrcase of chain length of dithiols. Using a correlation of peak position with the chain length, the active energies of 23-39 meV for dithiol SAMs of C6-C10 under an ac electric field were derived,
基金support from National Key Research and Development Program(2021YFA0717900)National Natural Science Foundation of China(62004138,52273190,52121002).
文摘Numerous reports have suggested that the performance of organic optoelectronic devices based on organicfieldeffect transistors(OFETs)is largely dependent on their interfaces.Self-assembled monolayers(SAMs)have been commonly used to engineer the interfaces of high-performance devices,particularly due to their well-defined structures and simple operation process through simple chemical adsorption growth.In this review,the structures of OFETs and SAM-modified OFETs are described,while different SAMs have been characterized.Furthermore,recent advances in the interface engineering of OFETs are described,the applicability of SAMs in functional devices of OFETs is reviewed,and existing problems and future developments in thisfield have been identified.
基金National Natural Science Foundation of China(Grant Nos.51925206,52302052)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0450301)+1 种基金Yunnan Provincial Science and Technology Project at Southwest United Graduate School(Grant No.202302AO370013)Huacai Solar Co.,Ltd.
文摘Self-assembled monolayers(SAMs)have recently emerged as excellent hole transport materials in inverted perovskite solar cells(PSCs)owing to their ability to minimize parasitic absorption,regulate energy level alignment,and passivate perovskite defects.Herein,we design and synthesize a novel dimethyl acridinebased SAM,[2-(9,10-dihydro-9,9-dimethylacridine-10-yl)ethyl]phosphonic acid(2PADmA),and employ it as a hole-transporting layer in inverted PSCs.Experimental results show that the 2PADmA SAM can modulate perovskite crystallization,facilitate carrier transport,passivate perovskite defects,and reduce nonradiative recombination.Consequently,the 2PADmA-based device achieves an enhanced power conversion efficiency(PCE)of 24.01%and an improved fill factor(FF)of 83.92%compared to the commonly reported[2-(9H-carbazol-9-yl)ethyl]phosphonic acid(2PACz)-based control device with a PCE of 22.32%and FF of 78.42%,while both devices exhibit comparable open-circuit voltage and short-circuit current density.In addition,2PADmA-based devices exhibit outstanding dark storage and thermal stabilities,retaining approximately~98%and 87%of their initial PCEs after 1080 h of dark storage and 400 h of heating at 85°C,respectively,both considerably superior to the control device.
文摘We investigate tunneling electron induced luminescence from isolated single porphyrin molecules that are decoupled by striped-phase self-assembled monolayer of octanethiol from the underneath Au（111） substrate. Intrinsic single-molecule electroluminescence has been realized by such decoupling at both bias polarities. The photon emission intensity acquired from the molecular lobe is found stronger than that from the molecular center. These re- sults provide useful information on the understanding of electroluminescent behavior and mechanism in molecular tunnel junctions.
基金Supported by the National Natural Science Foundation of China (20173040)
文摘The electrochemical behavior of trifluoperazine at decanethiol self-assembledmonolayer (SAM) modified gold electrodes (i. e. C_(10) H_(21) SH/Au) has been studied,Trifluoperazine can effectively accumulate on C_(10) H_(21) SH/Au electrodes and generate asensitive anodic peak at about 0.63 V (vs. SCE) in 0.05 mol/L pH 9.4 Na_2 B_4 O_7 buffer solution.Under the selected conditions, the anodic peak current was linear to trifluoperazine concentrationin the range of 5.0 X 10^(-7)-3.O X 10^(-3) mol/Lwith correlation coefficient of 0.997, thedetection limit was 3.0 X 10^(-5) mol/L. This method was applied to the determination oftrifluoperazine in drug samples and the recovery was 97.3%-104.0% It was found that sodium dodecylsulfate (SDS) could make the anodic peak current increase. In the presence of SDS, the peak at about0.63 V turned into two peaks, resulting from the change of the electrochemical mechanism.
文摘Self-assembly of octadecyl mercaptan on gold was investigated by cyclic voltammetry(CV) and electrochemical impedance spectroscopy (EIS). Results of CV experiments show thatthere are no structUral defects exposed directly to the redox couple in solution, but EISexperiments indicate that collapsed sites exist in the monolayer. A method to estimate the degree ofdisorder in the Au/thiol monolayer surface is proposed by using admittance plane plot.
文摘The carbon nanotube (fundamentally Single- walled carbon nanotube, SWCNT) based on 1-Amino-undecanethiol (AUT) were extremely controlled (nano-level) organizing a vertical self-assembled monolayer (SAM) on gold single crystal surfaces. The produced nano-surfaces were explored particularly by Fourier Transform Infra-red Spectroscopy (FT-IR), Cyclic Voltammetry (CV), Raman spectroscopy, Electrochemi- cal quartz crystal microbalance (EQCM), and Atomic force microscopy (AFM) techniques. The SWCNTs were initially cut (chemically) into short pipes and thiol-derivatized at the open ends. The vertical aggregation of SWCNT-AUTs on chemically refined Au(111) substrates was made-up by their spontaneous chemical bonding among carboxyl derivatized SWCNT-COOH and AUT SAM on Au(111), via peptide bonds, or directly by synthesized SWCNT-AUT composites. Raman spectroscopy and AFM surface images obviously disclosed that the SWCNT- AUT (dia. 20~40 nm) has been vertically categorized d on gold (111) substrates, shaping a SAM with a perpendicular direction.
基金financially supported by the Scientific Research Foundation of State Education Ministry of China (Jiaowaisiliu[2008]890)Research Foundation of Education Department of Hebei Province of China(No. 2007132)
文摘A mixed self-assembled monolayers （SAMs） of thioctic acid （T-COOH） and thioctic acid amide （T-NH2） were used to immobilize tyrosinase for fabricating biosensor. The results showed that the mixed SAMs prepared from solution at the ratio of 1：4 provided an excellent microenvironment for enzymatic reaction between tyrosinase and substrate. The biosensor exhibited a fast response and high sensitivity for sensing substrate.
基金supported by the National Natural Science Foundation of China(Nos.21506151,21576195 and 21776207)
文摘A thioester-functionalized triphenylamine hole-transporting molecule （TPD-SAc） was synthesized and self-assembled to form a monolayer on an ultra-thin Au film supported on indium-tin oxide glass. The modified surface was characterized by aqueous contact angle, ellipsometer, atomic force microscopy, X-ray photoelectron spectroscopy, and ultraviolet pho- toelectron spectrometer to substantiate the formation of compact and pinhole-free monolayers. The modified organic light emitting diode device [indium-tin oxide/Au （5 nm）/self-assembled monolayers （SAM）/TPD （50 nm）/Alq3 （40 nm）/TPBI （15 nm）/LiF （1 nm）/A1 （100 nm）] showed a luminance of 7303.90 cd/m^2 and a current efficiency of 8.49 cd/A with 1.78 and 2.29-fold increase, respectively, compared to the control device without SAM. The improvements were attributed to the enhanced compatibility of the organic-inorganic interface, matched energy level by introduction of an energy mediating step and superior hole-injection property of SAM molecules.
文摘Self assembled monolayers (SAMs) of to-mercapto methoxy poly(ethylene glycol)(MPEG) on gold electrode were used as a means to detect dopamine. Dopamine (DA) had good response at the MPEG film electrode and ascorbic acid (AA) was repelled from the SAMs. TheMPEG film is a biocompatible film, there was no adsorption of biosample and no inactivation atelectrode surface when it was used to detect DA in biosamples.
文摘The electrochemical quartz crystal microbalance (EQCM) is used to investigate the characteristics of the thiolated self-assembled monolayer(SAM) on gold surface.A 5MHz QCM element serves as both the mass-sensitive sensor and the working electrode of the electrochemical system.The 6-mecapto-1-hexanol and and the 16-mer oligonucleotide with a mercaptohexyl group at the 5'-phosphate end are utilized to form the SAM on the gold electrode.The frequency response of the QCM during cyclic voltammetry (CV) scanning and cbronoamperometry are recorded together with the electrochemical current.The experimental results indicates that the frequency response is more sensitive to the surface coverage.Therefore,the response of the EQCM reveals more details of the SAM on gold electrode.It is especially useful for analysing the immobilization quality,such as probe orientation and coverage,of the SAM.
基金Funded by National Natural Science Foundation of China (No. 50672055,50872077)National Key Technology R&D Program (No. 2006BAF02A28)the Graduate Innovation Fund of Shaanxi University of Science and Technology
文摘SrTiO3 thin film was successfully prepared on the functionalized organic self-assembled monolayers（SAMs） by the Liquid Phase Deposition（LPD） method.The as-prepared samples were characterized by X-ray diffraction（XRD）,atomic force microscope（AFM）,scanning electron microscopy（SEM） and metallographic microscope.Measurement of contact angle showed that the hydrophobe substrate was changed into hydrophile by UV irradiation.AFM photographs of octadecyl-trichloro-silane self-assembled monolayer（OTS-SAM） surface approved that UV irradiation did change the morphology of OTS monolayer and provided evidence for the conversion of hydrophilic characteristic.Photographs of Metallographic Microscope showed that OTS-SAM had an active effect on the deposition of SrTiO3 thin film.XRD and SEM indicated that the thin film was of pure cubic phase SrTiO3 and composed of nanosized grains with a size in the range of 100-500 nm.The formation mechanism of the SrTiO3 film was proposed.
基金Supported by the National Natural Science Foundation of Tianjin (No. 09JCZDJC25700, 12JCZDJC29600 and KJXH2011-11)
文摘Lipoic acid (LA) has received great attention in the area of gold surface functionalization. In this study, LA was employed as a linker for the attachment of antibody to the gold surface of surface plasmon resonance (SPR) chip. By using this chip in a homemade SPR immunosensor, low molecular weight compound 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) can be detected at a low level of 0.01 ng/mL. There is a good linear relationship(R2 =0.943 1) between the results of SPR biosensor and enzyme-linked immunosorbent assay(ELISA).
文摘A newly synthesized reagent 2-amino-5-mercapto-[1, 3, 4]triazole (MATZ) has been usedto fabricate self-assembled monolayers (SAMs) on gold electrode for the first time. The SAMselectrode was characterized by electrochemical methods and scanning electronic microscopy (SEM),the SAMs electrode can be used to determinate dopamine (DA) and uric acid (UA) simultaneouslywith a detection limit of 8×10-7 mol/L for DA and 1×10-6 mol/L for UA respectively. The SAMscan also be used to detect the contents of DA and UA in synthetic urine sample with satisfactoryresults.
文摘The orientation of the biological molecule immobi-lized on a solid surface has been critical in devel-opment of various applications. In this study, ori-entation of antibody was retained by protecting the antigen-binding site of the antibody prior to immo-bilization to -functionalized mixed self-assembled monolayer (SAM) of 12-mercaptododecanoic acid and 1-heptanethiol. More importantly, the number of immobilization bonds formed between each an-tigen-binding site protected antibody molecule and the solid surface was controlled by optimizing the mole fraction of the activated carboxyl group of the linker molecules in the mixed SAM. The amount of antibody used in this study was approximately equivalent to the amount for one monolayer surface coverage. The resulting activity of protected immo-bilized antibody was about 10 fold higher than that of random immobilized
基金Supported by the Japan Society for the Promotion of Science under Grant No JP25107004
文摘This work details a study based on HfS_(2 )transistors utilizing an n-octadecylphosphonic acid-based self-assembled monolayer(SAM)as the gate dielectric.The fabrication of the SAM-based two-dimensional(2D)material transistor is simple and can be used to improve the quality of the interface of air-sensitive 2D materials.In comparison to HfS_(2) transistors utilizing a conventional Al_2O_(3) gate insulator by atomic layer deposition,HfS_(2) transistors utilizing an SAM as the gate dielectric can reduce the operation region from 4 V to 2 V,enhance the field-effect mobility from 0.03 cm^2/Vs to 0.75 cm^2/Vs,improve the sub-threshold swing from 404 m V/dec to 156 m V/dec,and optimize the hysteresis to 0.03 V,thus demonstrating improved quality of the semiconductor/insulator interface.
