1
|
Yang C, Meng Y, Xie B, Xia S. Impacts of solvation on photo-damage of polypeptides: Modulation and biological implications. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2021; 220:112214. [PMID: 34049181 DOI: 10.1016/j.jphotobiol.2021.112214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 05/06/2021] [Accepted: 05/13/2021] [Indexed: 11/30/2022]
Abstract
We investigate the photon/matter interactions between soft X-rays and three selected polypeptides, poly-glycine (poly-Gly), poly-L-arginine (poly-Arg), and poly-l-lysine (poly-Lys), where the effects of molecular packing under the influence of solvent, e.g., water, substrates (Au foil or Si wafer) and X-ray irradiation under different durations were systematically investigated. Compared with negligible photo-damage on bare polypeptide powders, significantly enhanced degradation in pre-solvated polypeptides was observed likely because of the formation photo-generated radicals. X-ray photoemission spectroscopy (XPS) were employed as the analysis means to identify and quantify the chemical changes, especially the high-resolution photoemission spectra of C 1s, O 1s, N 1s and their evolution under continuous X-ray irradiation. The photo-degradation was found to preferentially occur on the CO entity in poly-Gly and the guanidinium group in poly-Arg. In poly-Arg, deprotonation occurs via the switch from zwittterionic to a neutral configuration, whereas poly-Lys deprotonates by directly losing the corresponding amine. The critical role of the interactions between amino acids, the building blocks of protein and almost all forms of biological activities, and the free-radical-generating living environment under irradiation was critically analyzed. The present study found that the preparation history of a sample, especially its inadvertent exposure to the sources of H2O, O2 and OH, could significantly alter the outcome of a radiation-related chemical process. Implications on the non-destructive probe of biologically important systems using physical methods involving X-rays were discussed as well.
Collapse
Affiliation(s)
- Chao Yang
- School of Life Science, Beijing Institute of Technology, Beijing 100081, China; Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Yue Meng
- School of Life Science, Huzhou University, 759 East Erhuan Road, Huzhou 313000, P R, China
| | - Bo Xie
- Department of Chemistry, College of Chemical Engineering, Zhejiang University of Technology, 18 Chaowang Road, Hangzhou 310014, P R, China
| | - Shengjie Xia
- Department of Chemistry, College of Chemical Engineering, Zhejiang University of Technology, 18 Chaowang Road, Hangzhou 310014, P R, China.
| |
Collapse
|
2
|
Zhao YW, Guo LE, Zhang FQ, Yao J, Zhang XM. Turn-On Fluorescence Enantioselective Sensing of Hydroxyl Carboxylic Enantiomers by Metal-Organic Framework Nanosheets with a Homochiral Tetracarboxylate of Cyclohexane Diamide. ACS APPLIED MATERIALS & INTERFACES 2021; 13:20821-20829. [PMID: 33887905 DOI: 10.1021/acsami.1c02897] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Two-dimensional (2D) metal-organic frameworks (MOFs) have attracted growing interest due to excellent performance in gas separation, energy conversion and storage, catalysis, and sensing, but their homochirality and exfoliation as well as related enantioselective catalysis and sensing remain a stage of pending exploration owing to the scarcity of homochiral MOFs and intrinsic aggregation of nanosheets. Herein, a homochiral 2D MOF (HMOF-3) with polymeric chirality, good thermostability, and solvent stability is designed and constructed by a homochiral organic ligand 5,5'-((1R,2R)-cyclohexane dicarbonyl bis(azanediyl)) diisophthalic acid (R,R-CHCAIP), a ditopic coligand 4,4'-bipyridine, and Zn salts. Remarkably, HMOF-3 can be exfoliated via solvent-assisted sonication to achieve 2D HMOF-3 nanosheets (HMOF-3-NS), which exhibit a sensitive turn-on effect with the fluorescence enhancement up to 63.5 times in the presence of R/S-mandelic acid, d/l-tartaric acid, d/l-lactic acid, d/l-alanine, and d/l-tryptophan. More importantly, the high surface area, polymeric chirality environment, and highly accessible functional sites on the surface of HMOF-3 nanosheets enable close contact with probed enantiomers, leading to highly enantioselective and sensitive sensing. The turn-on mechanism of host-guest-assisted electronic transfer is confirmed by DFT calculation and the relative experiment. This work highlights the promise of homochiral 2D MOF nanosheets for enantioselective sensing applications.
Collapse
Affiliation(s)
- Yan-Wu Zhao
- Key Laboratory of Magnetic Molecules & Magnetic Information Materials, Ministry of Education, School of Chemistry & Material Science, Shanxi Normal University, Linfen, Shanxi 041004, P. R. China
| | - Li-E Guo
- Key Laboratory of Magnetic Molecules & Magnetic Information Materials, Ministry of Education, School of Chemistry & Material Science, Shanxi Normal University, Linfen, Shanxi 041004, P. R. China
| | - Fu-Qiang Zhang
- Key Laboratory of Magnetic Molecules & Magnetic Information Materials, Ministry of Education, School of Chemistry & Material Science, Shanxi Normal University, Linfen, Shanxi 041004, P. R. China
| | - Jin Yao
- Key Laboratory of Magnetic Molecules & Magnetic Information Materials, Ministry of Education, School of Chemistry & Material Science, Shanxi Normal University, Linfen, Shanxi 041004, P. R. China
| | - Xian-Ming Zhang
- Key Laboratory of Magnetic Molecules & Magnetic Information Materials, Ministry of Education, School of Chemistry & Material Science, Shanxi Normal University, Linfen, Shanxi 041004, P. R. China
- College of Chemistry & Chemical Engineering, Key Laboratory of Interface Science and Engineering in Advanced Material, Ministry of Education,Taiyuan University of Technology, No. 79 Yingze West, Taiyuan, Shanxi 030024, P. R. China
| |
Collapse
|
3
|
Silva-Quinones D, He C, Dwyer KJ, Butera RE, Wang GT, Teplyakov AV. Reaction of Hydrazine with Solution- and Vacuum-Prepared Selectively Terminated Si(100) Surfaces: Pathways to the Formation of Direct Si-N Bonds. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:12866-12876. [PMID: 33086003 DOI: 10.1021/acs.langmuir.0c02088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The reactivity of liquid hydrazine (N2H4) with respect to H-, Cl-, and Br-terminated Si(100) surfaces was investigated to uncover the principles of nitrogen incorporation into the interface. This process has important implications in a wide variety of applications, including semiconductor surface passivation and functionalization, nitride growth, and many others. The use of hydrazine as a precursor allows for reactions that exclude carbon and oxygen, the primary sources of contamination in processing. In this work, the reactivity of N2H4 with H- and Cl-terminated surfaces prepared by traditional solvent-based methods and with a Br-terminated Si(100) prepared in ultrahigh vacuum was compared. The reactions were studied with X-ray photoelectron spectroscopy, atomic force microscopy, and scanning tunneling microscopy, and the observations were supported by computational investigations. The H-terminated surface led to the highest level of nitrogen incorporation; however, the process proceeds with increasing surface roughness, suggesting possible etching or replacement reactions. In the case of Cl-terminated (predominantly dichloride) and Br-terminated (monobromide) surfaces, the amount of nitrogen incorporation on both surfaces after the reaction with hydrazine was very similar despite the differences in preparation, initial structure, and chemical composition. Density functional theory was used to propose the possible surface structures and to analyze surface reactivity.
Collapse
Affiliation(s)
- Dhamelyz Silva-Quinones
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Chuan He
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Kevin J Dwyer
- Department of Physics, University of Maryland, College Park, Maryland 20742, United States
| | - Robert E Butera
- Laboratory for Physical Sciences, College Park, Maryland 20740, United States
| | - George T Wang
- Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Andrew V Teplyakov
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| |
Collapse
|
4
|
Yang N, Li W, Dong L. Modification of a H-terminated silicon surface by organic sulfide molecules: the mechanism and origin of reactivity. NEW J CHEM 2020. [DOI: 10.1039/c9nj06115k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
For the reactions of disulfide molecules (RSSR), the steric effect rather than the electronic effect of the R group is the main origin of the different reactivity. In the reactions of sulfide molecules (RSXR′, X = S, P, Si, O, N, C), charges on the S atom and dissociation energies of the S–X bonds have a great impact on the reactivity of these reactions.
Collapse
Affiliation(s)
- Na Yang
- Institute of Nuclear Physics and Chemistry
- China Academy of Engineering Physics
- Mianyang
- P. R. China
| | - Weiyi Li
- School of Science, Xihua University
- Chengdu
- P. R. China
| | - Liang Dong
- Institute of Nuclear Physics and Chemistry
- China Academy of Engineering Physics
- Mianyang
- P. R. China
| |
Collapse
|
5
|
High Surface Proton Conduction in Nanostructured ZIF-8. NANOMATERIALS 2019; 9:nano9101369. [PMID: 31554306 PMCID: PMC6835583 DOI: 10.3390/nano9101369] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 09/18/2019] [Accepted: 09/19/2019] [Indexed: 11/23/2022]
Abstract
The zeolitic imidazolate framework-8 (ZIF-8) combines a significantly high microporosity with an excellent thermal, chemical, and hydrothermal stability. Here, we demonstrated that ZIF-8 can display significant levels of protonic conductivity through a water-mediated surface transport mechanism associated to the presence of di-coordinated Zn ions revealed by X-ray photoelectron spectroscopy. A set of powders with particle sizes from 2.8 µm down to 80 nm studied by dynamic water vapour sorption analysis was used to demonstrate that water adsorbs predominantly in the micropore cavities of microcrystalline ZIF-8, whereas adsorption on the external surface becomes the dominant contribution for the nanostructured material. Impedance spectroscopy in turn revealed that the protonic conductivity of the nanocrystalline ZIF-8 was two orders of magnitude higher than that of the micron-sized powders, reaching approximately 0.5 mS·cm−1 at 94 °C and 98% relative humidity. Simple relations were derived in order to estimate the potential gains in water uptake and conductivity as a function of the particle size. This new strategy combining particle nanostructuring with surface defects, demonstrated here for one of the most know metal organic framework, is of general application to potentially boost the conductivity of other materials avoiding chemical functionalization strategies that in most if not all cases compromise their chemical stability, particularly under high humidity and high temperature conditions.
Collapse
|
6
|
He C, Teplyakov AV. 29,31- H Phthalocyanine Covalently Bonded Directly to a Si(111) Surface Retains Its Metalation Ability. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:10880-10888. [PMID: 30136849 DOI: 10.1021/acs.langmuir.8b02259] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The reaction of metal-free phthalocyanine molecules with a chlorine-terminated Si(111) surface is investigated to produce a phthalocyanine functionality directly attached to a semiconductor surface, without additional linkers or layers. The carefully prepared Cl-Si(111) surface provides an oxygen-free substrate that is reacted with 29,31- H phthalocyanine (H2Pc) in a wet-chemistry process resulting in HCl elimination. The in situ metalation of this H2Pc-modified silicon surface with cobalt is confirmed, suggesting that the produced functionality is chemically active. These processes are investigated by X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and time-of-flight secondary ion mass spectrometry supplemented by density functional theory calculations. The morphology of the surface is monitored by atomic force microscopy. The combined spectroscopic, microscopic, and theoretical investigations demonstrate that additional linkers are not required for phthalocyanine attachment to occur, as the direct attachment can take place by forming Si-N bonds, and that the resulting surface species can participate in a metalation process.
Collapse
Affiliation(s)
- Chuan He
- Department of Chemistry and Biochemistry , University of Delaware , Newark DE 19716 , United States
| | - Andrew V Teplyakov
- Department of Chemistry and Biochemistry , University of Delaware , Newark DE 19716 , United States
| |
Collapse
|
7
|
Huey WLB, Goldberger JE. Covalent functionalization of two-dimensional group 14 graphane analogues. Chem Soc Rev 2018; 47:6201-6223. [DOI: 10.1039/c8cs00291f] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The sp3-hybridized group 14 graphane analogues are a unique family of 2D materials in which every atom requires a terminal ligand for stability.
Collapse
Affiliation(s)
- Warren L. B. Huey
- Department of Chemistry and Biochemistry
- The Ohio State University
- Columbus
- USA
| | | |
Collapse
|
8
|
Gao F, Teplyakov AV. Monolayer of Hydrazine Facilitates the Direct Covalent Attachment of C 60 Fullerene to a Silicon Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:8632-8639. [PMID: 28157324 PMCID: PMC5554729 DOI: 10.1021/acs.langmuir.6b03975] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The development of oxygen-free organic-inorganic interfaces has led to new schemes for the functionalization of silicon surfaces with nitrogen-based chemical groups. However, building layers of large structures directly on this functionalized surface has remained elusive. This work confirms the path to form a stable interface between silicon and buckminsterfullerene C60 based on covalent chemical bonds. The starting point for this modification is the hydrazine-reacted Si(111) surface with the diamine functionality, which is further reacted directly with the C60 molecules. The chemistry of this process is confirmed spectroscopically and microscopically and can be used to form organic-inorganic interfaces separated by a single layer of nitrogen.
Collapse
|
9
|
Williams MG, Gao F, BenDhiab I, Teplyakov A. Carbon Nanotubes Covalently Attached to Functionalized Surfaces Directly through the Carbon Cage. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:1121-1131. [PMID: 28166639 PMCID: PMC5484583 DOI: 10.1021/acs.langmuir.6b02641] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The covalent attachment of nonfunctionalized and carboxylic acid-functionalized carbon nanotubes to amine-terminated organic monolayers on gold and silicon surfaces is investigated. It is well established that the condensation reaction between a carboxylic acid and an amine is a viable method to anchor carbon nanotubes to solid substrates. The work presented here shows that the presence of the carboxylic group on the nanotube is not required for attachment to occur, as direct attachment via the substrate amine and the nanotube cage can take place. Scanning and transmission electron microscopy and atomic force microscopy confirm the presence of carbon nanotubes in intimate contact with the surface. X-ray photoelectron spectroscopy is utilized to compare the surface chemistry of the functionalized and nonfunctionalized carbon nanotubes and is supported by a computational investigation. Ion fragments attributed to the direct attachment between the surface and carbon nanotube cage are detected by time-of-flight secondary ion mass spectrometry. The overall attachment scheme is evaluated and can be further used on multiple carbonaceous materials attached to solid substrates.
Collapse
Affiliation(s)
- Mackenzie G. Williams
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Fei Gao
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | | | - Andrew Teplyakov
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| |
Collapse
|
10
|
Williams MG, Teplyakov AV. Building High-Coverage Monolayers of Covalently Bound Magnetic Nanoparticles. APPLIED SURFACE SCIENCE 2016; 388:461-467. [PMID: 27789916 PMCID: PMC5076859 DOI: 10.1016/j.apsusc.2015.11.212] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This work presents an approach for producing a high-coverage single monolayer of magnetic nanoparticles using "click chemistry" between complementarily-functionalized nanoparticles and a flat substrate. This method highlights essential aspects of the functionalization scheme for substrate surface and nanoparticles to produce exceptionally high surface coverage without sacrificing selectivity or control over the layer produced. The deposition of one single layer of magnetic particles without agglomeration, over a large area, with a nearly 100% coverage is confirmed by electron microscopy. Spectroscopic techniques, supplemented by computational predictions, are used to interrogate the chemistry of the attachment and to confirm covalent binding, rather than attachment through self-assembly or weak van der Waals bonding. Density functional theory calculations for the surface intermediate of this copper-catalyzed process provide mechanistic insight into the effects of the functionalization scheme on surface coverage. Based on this analysis, it appears that steric limitations of the intermediate structure affect nanoparticle coverage on a flat solid substrate; however, this can be overcome by designing a functionalization scheme in such a way that the copper-based intermediate is formed on the spherical nanoparticles instead. This observation can be carried over to other approaches for creating highly-controlled single- or multilayered nanostructures of a wide range of materials to result in high coverage and possibly, conformal filling.
Collapse
Affiliation(s)
- Mackenzie G. Williams
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Andrew V. Teplyakov
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| |
Collapse
|
11
|
Gao F, Teplyakov AV. Dehydrohalogenation Condensation Reaction of Phenylhydrazine with Cl-Terminated Si(111) Surfaces. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2016; 120:5539-5548. [PMID: 27822334 PMCID: PMC5096846 DOI: 10.1021/acs.jpcc.5b12424] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Formation of stable organic-inorganic contacts with silicon often requires oxygen- and carbon-free interfaces. Some of the general approaches to create such interfaces rely on the formation of a Si-N bond. A reaction of dehydrohalogenation condensation of Cl-terminated Si(111) surface with phenylhydrazine is investigated as a means to introduce a simple function to the surface using a -NH-NH2 moiety as opposed to previously investigated approaches. The use of substituted hydrazine allows for the formation of a stable structure that is less strained compared to the previously investigated primary amines and leads to minimal surface oxidation. The process is confirmed by a combination of infrared studies, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry investigations. Density functional theory is utilized to yield a plausible surface reaction mechanism and provide a set of experimental observables to compare with these data.
Collapse
|
12
|
Duan Y, Gao F, Teplyakov AV. Role of the Deposition Precursor Molecules in Defining Oxidation State of Deposited Copper in Surface Reduction Reactions on H-Terminated Si(111) Surface. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2015; 119:27018-27027. [PMID: 27482303 PMCID: PMC4959445 DOI: 10.1021/acs.jpcc.5b08287] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Surface-limited deposition reactions leading to the formation of copper nanoparticles on H-terminated Si(111) surface can serve as a model for understanding the role of structure of the deposition precursor molecules in determining the oxidation state of the metal deposited. This study compares three different precursor molecules: Cu(acac)2 (Cu(II) acetylacetonate), Cu(hfac)2, and Cu(hfac)VTMS (Cu(I)-(hexafluoroacetylacetonato)-vinyltrimethylsilane) as copper deposition sources in a process with a controlled oxidation state of copper. X-ray photoelectron spectroscopy suggests that single-electron reduction governs the deposition of Cu(I) from the first two precursor molecules and that the last of the precursors studied yields predominantly metallic copper. Time-of-fight secondary ion mass spectrometry (ToF-SIMS) and infrared spectroscopy are utilized to interrogate surface species produced. Atomic force microscopy is used to quantify the deposition process and to follow the size distribution of the deposited copper containing nanoparticles. A plausible explanation supported by density functional theory calculations is offered on the basis of the difference in the reaction pathways for Cu(I) and Cu(II) precursors.
Collapse
|
13
|
Tao Y, Navaretti P, Hauert R, Grob U, Poggio M. Permanent reduction of dissipation in nanomechanical Si resonators by chemical surface protection. NANOTECHNOLOGY 2015; 26:465501. [PMID: 26501931 DOI: 10.1088/0957-4484/26/46/465501] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report on mechanical dissipation measurements carried out on thin (∼100 nm), single-crystal silicon cantilevers with varying chemical surface termination. We find that the 1-2 nm-thick native oxide layer of silicon contributes about 85% to the friction of the mechanical resonance. We show that the mechanical friction is proportional to the thickness of the oxide layer and that it crucially depends on oxide formation conditions. We further demonstrate that chemical surface protection by nitridation, liquid-phase hydrosilylation, or gas-phase hydrosilylation can inhibit rapid oxide formation in air and results in a permanent improvement of the mechanical quality factor between three- and five-fold. This improvement extends to cryogenic temperatures. Presented recipes can be directly integrated with standard cleanroom processes and may be especially beneficial for ultrasensitive nanomechanical force- and mass sensors, including silicon cantilevers, membranes, or nanowires.
Collapse
Affiliation(s)
- Y Tao
- Department of Physics, ETH Zurich, Otto Stern Weg 1, 8093 Zurich, Switzerland. Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge MA 02139, USA
| | | | | | | | | |
Collapse
|
14
|
Li F, Basile VM, Pekarek RT, Rose MJ. Steric spacing of molecular linkers on passivated Si(111) photoelectrodes. ACS APPLIED MATERIALS & INTERFACES 2014; 6:20557-20568. [PMID: 25354387 DOI: 10.1021/am506244m] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Surfaces with high photoelectrochemical and electronic quality can be prepared by tethering small molecules to single-crystalline Si(111) surfaces using a two-step halogenation/alkylation method (by Lewis and co-workers).1-7 We report here that the surface coverage of custom-synthesized, phenyl-based molecular linkers can be controlled by varying the steric size of R-groups (R=CH3, C6H11, 2-ethylhexyl) at the periphery of the linker. Additionally, the linkers possess a para triflate group (-O2SCF3) that serves as a convenient analytical marker and as a point of covalent attachment for a redox active label. Quantitative X-ray photoelectron spectroscopy (XPS) measurements revealed that the surface coverage systematically varies according to the steric size of the linker: CH3 (6.7±0.8%), CyHex (2.9±1.2%), EtHex (2.1±0.9%). The stability of the photoelectrochemical cyclic voltammetry (PEC-CV) behavior was dependent on an additional methylation step (with CH3MgCl) to passivate residual Si(111)-Cl bonds. Subsequently, the triflate functional group was utilized to perform Pd-catalyzed Heck coupling of vinylferrocene to the surface-attached linkers. Ferrocene surface coverages measured from cyclic voltammetry on the ferrocene-functionalized surfaces Si(111)-8a/CH3-Fc (R=CH3) and Si(111)-8c/CH3-Fc (R=2-EtHex) are consistent with the corresponding Fe 2p XPS coverages and suggest a ∼1:1 conversion of surface triflate groups to vinyl-Fc sites. The surface defect densities of the linker/CH3 modified surfaces are dependent on the coverage and composition of the organic layer. Surface recombination velocity (SRV) measurements indicated that n-Si(111)-8a/CH3 and the ferrocene coupled n-Si(111)-8a/CH3-Fc exhibited relatively high surface carrier lifetimes (4.51 and 3.88 μs, respectively) and correspondingly low S values (3880 and 4510 cm s(-1)). Thus, the multistep, linker/Fc functionalized surfaces exhibit analogously low trap state densities as compared to the fully passivated n-Si(111)-CH3 surface.
Collapse
Affiliation(s)
- Feng Li
- Department of Chemistry, The University of Texas at Austin , Austin, Texas 78712-1224, United States
| | | | | | | |
Collapse
|
15
|
Miller T, Teplyakov AV. Attachment chemistry of PCBM to a primary-amine-terminated organic monolayer on a Si(111) surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:5105-5114. [PMID: 24735094 DOI: 10.1021/la404798k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Interfacing multifunctional molecules with semiconductor surfaces has a variety of applications; however, it is important to understand the selectivity of target surface reactions to produce the surface with desired functionality. In this work, a silicon surface modified with 1-amino-10-undecene was reacted with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) in toluene. Two possible competing reactions for PCBM, via the ester group and by direct attachment to the C60 portion, are analyzed. X-ray photoelectron spectroscopy, atomic force microscopy, Fourier-transform infrared spectroscopy, and time-of-flight secondary ion mass spectroscopy, supplemented by density functional theory calculations, suggest that despite the similarity of the energetics for those two reaction pathways, predominant chemisorption occurs via the direct attachment of the C60 cage to the primary amino group of the functionalized silicon surface.
Collapse
Affiliation(s)
- Timothy Miller
- Department of Chemistry and Biochemistry, University of Delaware , Newark, Delaware 19716, United States
| | | |
Collapse
|
16
|
Lin JM, Teplyakov AV. Computational investigation of surface reactivity of functionalized silicon surfaces in deposition processes. Theor Chem Acc 2013. [DOI: 10.1007/s00214-013-1404-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
17
|
Metal complex oligomer and polymer wires on electrodes: Tactical constructions and versatile functionalities. POLYMER 2013. [DOI: 10.1016/j.polymer.2013.04.019] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
18
|
Tian F, Teplyakov AV. Silicon surface functionalization targeting Si-N linkages. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:13-28. [PMID: 23094599 DOI: 10.1021/la303505s] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Silicon substrates have been a fascinating topic of fundamental and applied research for well over 50 years. They have attracted even more attention over the last couple of decades with advances in chemical functionalization that made oxide-free silicon surfaces a reality. Fundamentally new electronic properties and chemical reactivity became available, and the focus of chemical research turned more toward targeting specific chemical bonds and functionalities on silicon. Although thermodynamics clearly drives most processes under ambient conditions toward the formation of an oxide layer, kinetic control of the oxidation processes and thermodynamic tricks based on gaining stability of surface monolayers with high-density assembly have allowed for the formation of stable Si-C bonds and Si-O-C linkages on oxide-free silicon crystals. This feature article targets recent advances in making Si-N linkages on the same oxide-free single crystals. It covers the range of chemical approaches to achieving this goal and offers possible chemistry that can take advantage of the systems produced. The present status of the field and the future directions of its development will be considered.
Collapse
Affiliation(s)
- Fangyuan Tian
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | | |
Collapse
|