Charge storage investigation in self-assembled monolayer of redox-active recombinant azurin

Sang-Uk Kim,Ajay Kumar Yagati,Ravindra P. Singh,Junhong Min,최정우 한국물리학회 2009 Current Applied Physics Vol.9 No.2

Charge storage in nanoscaled monolayer of recombinant azurin by using direct self-assembly method was investigated for the construction of bioelectronic devices. Recombinant azurin having a cysteine residue was utilized to enhance the stability of the self-assembled protein on the gold surface without any chemical linker. We investigated the immobilization of protein by surface plasmon resonance and scanning tunneling microscopy. The electrochemical properties of recombinant azurin immobilized on the surface were confirmed by cyclic voltammetry. The memory device characteristics, including the ‘‘Read”, ‘‘Write”, and ‘‘Erase” functions of the self-assembled azurin layer, were obtained with three distinct electrical states of the azurin layers by cyclic voltammetry. It was concluded that the proposed device had a memory function and could be used for the construction of a nanobiochip with memory function. Charge storage in nanoscaled monolayer of recombinant azurin by using direct self-assembly method was investigated for the construction of bioelectronic devices. Recombinant azurin having a cysteine residue was utilized to enhance the stability of the self-assembled protein on the gold surface without any chemical linker. We investigated the immobilization of protein by surface plasmon resonance and scanning tunneling microscopy. The electrochemical properties of recombinant azurin immobilized on the surface were confirmed by cyclic voltammetry. The memory device characteristics, including the ‘‘Read”, ‘‘Write”, and ‘‘Erase” functions of the self-assembled azurin layer, were obtained with three distinct electrical states of the azurin layers by cyclic voltammetry. It was concluded that the proposed device had a memory function and could be used for the construction of a nanobiochip with memory function.

Effects of Pt shell thickness on self-assembly monolayer Pd@Pt core-shell nanocrystals based hydrogen sensing

Uddin, A.S.M. Iftekhar,Yaqoob, Usman,Hassan, Kamrul,Chung, Gwiy-Sang Elsevier 2016 International journal of hydrogen energy Vol.41 No.34

<P><B>Abstract</B></P> <P>In the current contribution, Pd@Pt core-shell nanocrystals-based resistivity-type sensor has been realized with the aim of implementing a fast-response hydrogen (H<SUB>2</SUB>) sensor and investigating the effect of shell thickness on sensing properties. Pd@Pt core-shell nanocrystals as colloids were synthesized via a chemical route and were then carefully assembled on a SiO<SUB>2</SUB>/Si substrate using the self-assembly monolayer (SAM) technique. Three different Pd@Pt core-shell nanocrystals with varied Pt shell thicknesses were synthesized for the SAM process. The short diffusion length of Pd@Pt due to the thin Pt shell layer and the monolayer distribution of the Pd@Pt core-shell preferentially accelerated the adsorption–desorption of the H<SUB>2</SUB> molecules on the sensing interface, resulting in a very quick response to H<SUB>2</SUB> gas. At an optimum operating temperature of 150 °C, the sensor showed a fast-response time of 6 s, a maximum response of 3.6% to 1 vol.% gas concentration, and a broad detection range of 0.001–4 vol.% H<SUB>2</SUB> concentrations. The aforementioned outcomes of the as-fabricated sensor demonstrate the possibility of implementing an efficient H<SUB>2</SUB> sensor for safety applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Synthesis of Pd@Pt core-shell nanocrystals in a facile and rapid chemical route. </LI> <LI> Deposition of Pd@Pt core-shell through self-assembly monolayer technique. </LI> <LI> Role of monolayer distribution in fast H<SUB>2</SUB> sensing. </LI> <LI> Effect of Pt shell thickness in adsorption–desorption of the H<SUB>2</SUB> molecules. </LI> </UL> </P>

Self assembled-monolayer(SAM)법을 이용한 TaN 확산방지막의 무전해 Cu 도금용 Pd seed layer 제조 및 특성

한원규,조진기,최재웅,김정태,염승진,곽노정,김진웅,강성군,Han, Won-Kyu,Cho, Jin-Ki,Choi, Jae-Woong,Kim, Jeong-Tae,Yeom, Seung-Jin,Kwak, Noh-Jung,Kim, Jin-Woong,Kang, Sung-Goon 한국재료학회 2007 한국재료학회지 Vol.17 No.9

Electroless deposition(ELD) was applied to fabricate Cu interconnections on a TaN diffusion barrier with Pd seed layer. The Pd seed layer was obtained by self-assembled monolayer method(SAM) with PDDA and PSS as surfactants. We were able to obtain about 10nm Pd nano particles as seeds for electroless Cu deposition and the density of Pd seeds was much higher than that of Pd seeds fabricated by conventional Pd sensitization-activation method. Also we were able to obtain finer Cu interconnections by ELD. Therefore we concluded that the Pd seed layer by SAM was able to be applied to form Cu interconnection by ELD for under 30nm feature.

STM Study of 2-Mercaptoethanol Self-Assembled Monolayer on Au(111)

현문섭,이충균,Hyeon, Mun Seop,Lee, Chung Gyun Korean Chemical Society 2001 Bulletin of the Korean Chemical Society Vol.22 No.2

Presented are the STM images of self-assembled monolayer of 2-mercaptoethanol on Au(111). Striped structures of ($6{\times}3_{\frac{1}{2}}$), ($5{\times}3_{\frac{1}{2}}$), ($4{\times}3_{\frac{1}{2}}$) and compact-($5{\times}3_{\frac{1}{2}}$) were observed after annealing at $80^{\circ}C.$ Analysis of the ordered structures revealed that the basic fundamental units of the ordered structures were three crystallographically non-equivalent ($3_{\frac{1}{2}}{\times}3_{\frac{1}{2}}$) $R30^{\circ}$ assemblies, and that the way of combination of the assemblies produced the four different structures. The($6{\times}3_{\frac{1}{2}}$) structure ( $\theta$ = 0.33) was composed of one ($3_{\frac{1}{2}}{\times}3_{\frac{1}{2}}$)$R30^{\circ}$ assembly, while the ($5{\times}3_{\frac{1}{2}}$) ( $\theta$ = 0.30) and ($4{\times}3_{\frac{1}{2}}$) ( $\theta$ = 0.38) structures were consisted of two ($3_{\frac{1}{2}}{\times}3_{\frac{1}{2}}$) $R30^{\circ}$ assemblies, separated by 5a and 4a, respectively. Furthermore, the compact-(5X 3½) structure ( $\theta$ = 0.50) was obtained by overlapping three ($3_{\frac{1}{2}}{\times}3_{\frac{1}{2}}$) $R30^{\circ}$ assemblies. In spite of the diversity in the adsorption structures, all the adsorption sites of 2-mercaptoethanol were fundamentally identical. On the other hand, the unannealed primitive SAM of 2-mercaptoethanol was characterized by two observations: a short-range order keeping the adsorbed molecules at approximately $3_{\frac{1}{2}}$ a and the small domains of the striped structures supporting that the observed surface structures on the annealed surface were the extension of the primitive layer of 2-mercaptoethanol. Comparing these observations with the already published structures of ethanthiol, it was concluded that the interaction between the hydroxyl groups of 2-mercaptoethanol might play a significant role in the adsorption step of 2-mercaptoethanol on Au(111) to organize the adsorption structures different from those of ethanthiol.

Thin Film Micromachining Using Femtosecond Laser Photo Patterning of Organic Self-assembled Monolayers

Won-Seok Chang,Moo-Jin Choi,Jae-Gu Kim,Sung-Hak Cho,Kyung-Hyun Whang 한국정밀공학회 2006 International Journal of Precision Engineering and Vol.7 No.1

Self-Assembled Monolayers (SAMs) formed by alkanethiol adsorption to thin metal film are widely being investigated for applications as coating layer for anti-stiction or friction reduction and in fabrication of micro structure of molecules and bio molecules. Recently, there have been many researches on micro patterning using the advantages of very thin thickness and etching resistance of Self-Assembled Monolayers in selective etching of thin metal film. In this report, we present the several machining method to form the nanoscale structure by Mask-Less laser patterning using alknanethiolate Self-Assembled Monolayers such as thin metal film etching and heterogeneous SAM structure formation.

대류성 자기조립법을 통한 폴리스티렌 비드 대면적 단일층 형성에 미치는 공정 변수 효과

서안나,최지환,변재철,김원목,김인호,이경석,Seo, Ahn-na,Choi, Ji-Hwan,Pyun, Jae-chul,Kim, Won Mok,Kim, Inho,Lee, Kyeong-Seok 한국재료학회 2015 한국재료학회지 Vol.25 No.12

Self-assembled monolayers(SAM) of microspheres such as silica and polystyrene(PS) beads have found widespread application in photonic crystals, sensors, and lithographic masks or templates. From a practical viewpoint, setting up a high-throughput process to form a SAM over large areas in a controllable manner is a key challenging issue. Various methods have been suggested including drop casting, spin coating, Langmuir Blodgett, and convective self-assembly(CSA) techniques. Among these, the CSA method has recently attracted attention due to its potential scalability to an automated high-throughput process. By controlling various parameters, this process can be precisely tuned to achieve well-ordered arrays of microspheres. In this study, using a restricted meniscus CSA method, we systematically investigate the effect of the processing parameters on the formation of large area self-assembled monolayers of PS beads. A way to provide hydrophilicity, a prerequisite for a CSA, to the surface of a hydrophobic photoresist layer, is presented in order to apply the SAM of the PS beads as a mask for photonic nanojet lithography.

Self-Assembled Monolayer Treated ZnO by Benzoic Acid Derivatives in Organic Solar Cells

( Ratna Dewi Maduwu ),김동근,진호철,( Sabrina Aufar Salma ),김주현 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0

Self-assembled monolayer (SAM) molecule derivatives from benzoic acid, such as 4-methoxybenzoic acid (MBA), 4-tertbutylbenzoic acid (BBA), and 4-fluorobenzoic acid (FBA), have different dipole orientation and magnitude. In this study, these benzoic acid derivatives were used as an electron injection/transporting layer in inverted type organic solar cells (OSCs) with a structure of ITO/SAM treated ZnO/active layer (P3HT:PC₆₁BM)/MoO₃/Ag, and then the performances of each are compared. The results showed that the power conversion efficiency (PCE) and the open circuit voltage (Voc) values of the devices based on ZnO/MBA and ZnO/BBA treated ZnO showed better performances than other devices. This can be caused by the direction of dipole moment of benzoic acid derivatives. Accordingly, this work provides an alternative strategy to improve the interface property between inorganic and organic materials in organic electronic devices by SAM treatment on the ZnO surface

Thin Film Micromachining Using Femtosecond Laser Photo Patterning of Organic Self-assembled Monolayers

Chang Won-Seok,Choi Moo-Jin,Kim Jae-Gu,Cho Sung-Hak,Whang Kyung-Hyun Korean Society for Precision Engineering 2006 International Journal of Precision Engineering and Vol.7 No.1

Self-Assembled Monolayers (SAMs) formed by alkanethiol adsorption to thin metal film are widely being investigated for applications as coating layer for anti-stiction or friction reduction and in fabrication of micro structure of molecules and bio molecules. Recently, there have been many researches on micro patterning using the advantages of very thin thickness and etching resistance of Self-Assembled Monolayers in selective etching of thin metal film. In this report, we present the several machining method to form the nanoscale structure by Mask-Less laser patterning using alknanethiolate Self-Assembled Monolayers such as thin metal film etching and heterogeneous SAM structure formation.

XPS와 AFM에 의한 올리고펩타이드의 자기 집합화 단분자막 분석

송성훈,박진영,김우식,Nakamura, Chikashi,Miyake, Jun,장상목 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.1

금속 기판 위에 유기 박막을 형성하는 방법 중에서 티올기와 Au와의 결합을 이용한 자기집합에 관한 연구가 활발히 진행되고 있다. 포르피린 유도체와 강하게 결합하는 타올기를 가지는 올리고펩타이드 PSP1과 PSP2를 합성하여 MOPS 완층용액에서 금표면에 자기집합화 단분자막(self-assembled monolayer, SAM)을 형성시켜 X-ray photoelection spectroscopy(XPS)와 atomic force microscopy(AFM)을 이용하여 분석하였다. 그 결과 PSP2의 경우와 PSP1의 경우보다 Au표면에서 SAM이 더욱 더 잘 형성되고 있음을 알 수 있었고 MOPS완충용액에 존재하는 황 이온의 영향도 알 수 있었다. 이 결과는 구성단위로부터 이론적으로 계산한 SAM막의 steric energy 값의 차이에서 유추한 결론과 일치하였다. Recently, the self-assembled monolayer(SAM) of thiols on nible metals has been studied intensively. Oligopeptides such as PSP1(Tyr-Ala-Gly-Tyr-Cys) and PSP2(His-Ala-Ser-Cys) with thiol group, which interact strongly with a typical cationic porphyrin derivative, are synthesized. Peptides adsorption from the liquid phase on Au has been studied using X-ray photoelection spectroscopy(XPS) and AFM image. XPS provides further evidence that the primary adsorbate species is bonded to Au through the sulfur atom. By the analysis of XPS spectra and AFM image, it is found that PSP2 is self-assembled better than PSP1 and the sulfur ion MOPS buffer solution has an effect on the self-assembling performance. This result is coincident with the calculation result of steric energies of Au-Peptide bonded SAM structure.

Surface-Grafted Rodlike Polymers: Adaptive Self-Assembled Monolayers and Rapid Photo-Patterning of Surfaces

Han, Mingu,Rahman, M. Shahinur,Lee, Jae-Suk,Khim, Dongyoon,Kim, Dong-Yu,Park, Ji-Woong American Chemical Society 2011 Chemistry of materials Vol.23 No.15

<P>We present a new concept of functionalizing solid surfaces using polymeric self-assembled monolayers (PSAM) that are obtained by grafting onto solid surfaces an asymmetric block copolymer composed of a long rodlike block and a short surface-reactive block. Poly(n-hexylisocyanate)-<I>b</I>-poly[3-(trimethoxysilyl)propyl methacrylate] (PHIC-<I>b</I>-PTMSM) is synthesized via a living anionic polymerization and an atom transfer radical polymerization. The new rod–coil block copolymer forms a polymeric self-assembled monolayer (PSAM) through covalent bonding of the sticky PTMSM block and planar adsorption of PHIC rodlike chains onto the substrate surface. The uniform PSAM with a thickness identical to the diameter of the rodlike chain is produced by the immersion coating method in a range of immersion solution concentrations and coating times. The PSAMs present unique properties thanks to the freedom of rotation of the end-grafted rodlike chains. The PSAMs exhibit nematic liquid crystalline ordering when the monolayer is fluidized by solvent vapor. A mixed SAM with a nanodot pattern is obtained by introducing a second coating agent of octadecyltrimethoxysilanes (ODTMS) onto the PSAM-coated substrate. The PSAM is micropatternable using photochemical cleavage of the anchoring blocks by brief exposure to UV. Use of the PSAMs as an additional dielectric layer in P3HT-based field effect transistors (FETs) is also demonstrated.</P><P>Rodlike polymers are covalently tethered to the surface to yield a polymeric self-assembled monolayer (PSAM). Thanks to noncovalent adsorption of planar rods, the PSAMs exhibit unique properties such as liquid crystalline order, the reactivity toward an additional surface-modifying agent to generate a mixed SAM, and the capability of photochemical patterning.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2011/cmatex.2011.23.issue-15/cm201138u/production/images/medium/cm-2011-01138u_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm201138u'>ACS Electronic Supporting Info</A></P>