bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nanoparticle Imprinted Polymers As Sensing Layers for Size-Selective Recognition of Silver Nanoparticles
Authors: Witt Julia , Mandler Daniel , Wittstock Gunther 
Published: February 2020

The expected broad utilisation of nanoparticles (NPs) calls for a detailed consideration of their specific toxicological effects and monitoring their release into the environment (nanotoxicology).[1] Appropriate in vitro sensing tools should provide information about the possible interaction between nanoobjects (characterized by core material, size, shell chemistry and shape) and biological systems. Recently, we published a new concept based on nanoparticle-imprinted polymers (NIPs, Figure 1) combined with electrochemical detection.[2] The new sensor principle was first demonstrated with a polyaniline film transferred simultaneously with template AuNPs by the Langmuir-Blodgett technique.
Here we demonstrate the extension of this concept to other matrix systems and other strategies for building NIPs. AuNPs with a diameter of 30 nm were arranged as templates on a 3-aminopropyltriethoxysilan (APTES)-modified indium tin oxide (ITO) electrode. Electrostatic interactions between negatively charged AuNPs and the positively charged monolayer enabled a controlled assembly of dispersed NPs as evidenced by scanning electron microscopy (SEM) and scanning force microscopy (SFM). Subsequently, a polymer matrix is generated either by electropolymerisation of self-inhibiting poly(phenol) and poly(plumbagin) films or by spin-coating an ultrathin poly(dimethylsiloxane) (PDMS) layer. SFM images proved the presence of templates within smooth, 5 to 20 nm thick matrices. Template NPs were chemically removed in potassium cyanide, leaving their shape and size imprinted in the polymer as evidenced by different techniques like SEM and Pulsed Force Microscopy (PFM). The recognition ability and size selectivity of NIPs was investigated by immersing the matrix in aqueous solutions containing citrate-capped AgNPs overnight. The presence of analyte AgNPs was verified electrochemically in an aqueous NaNO3 solution as by LSV. Complementing studies by UV-Vis and X-ray photoelectron spectroscopies corroborated the template embedding, template release and analyte NP uptake.
References
[1] A. Nel, T. Xia, L. Mädler, N. Li, Science 311 (2006) 622.
[2] S. Kraus-Ophir, J. Witt, G. Wittstock, D. Mandler, Angew. Chem. Int. Ed. 53 (2014) 294.

Figure 1
Glassy Carbon Electrode As a Promising Sensor for Healthcare and Environmental Monitoring
Authors: Chatterjee Sanghamitra , Chen Aicheng 
Published: February 2020

Glassy carbon electrode (GCE) has been explored in the present investigations and applied thereafter for biomedical applications and environmental monitoring. A novel electrochemical approach for the quantitative analysis of methylglyoxal as a biomarker in human plasma has been developed. An electrochemical sensor employing a single walled carbon nanotube modified GCE for the sensitive detection of methylglyoxal is delineated for the first time employing square wave voltammetry. This modified electrode exhibits potent and sustained electron-mediating behavior and a well-defined reduction peak in response to methylglyoxal was observed. The interfering effect of common coexisting metabolites in human whole blood has also been investigated. The developed assay was shown to be specific and sensitive for the analysis of plasma levels of methylglyoxal in healthy volunteer and diabetic patients.
A simple, rapid and highly selective method for the determination of the most abundant α-dicarbonyl compound in wine and beer has been developed for the first time by employing square wave voltammetry. A novel electrochemical sensor, based on the electrodeposition of platinum nanoparticles onto single wall carbon nanotubes that were casted on a GCE substrate has been developed. This modified electrode was successfully applied for the quantitative analysis of methylglyoxal in wine and beer samples. The developed sensor possesses advantageous properties such as a high active surface area, stability, and a rapid electron transfer rate, which cumulatively demonstrate high performance toward the electrocatalytic reduction and detection of methylglyoxal.
A promising direct and simultaneous electrochemical determination method of phenolic pollutants in wastewater samples was constructed successfully on GCE with advantages being rapid, simple, convenient, sensitive, in situ and inexpensive. The electrochemical characteristics of multi-component phenolic pollutants, such as phenol and 4-nitrophenol were investigated on GCE employing square wave voltammetry technique. Each of them displayed good linear relationship between their oxidation peak currents and their corresponding concentrations in a rather wide range coexisting with the other phenolic pollutant. The effect of different experimental and instrumental parameters such as solution pH and square wave frequency were examined. Square wave voltammetry was employed to investigate the electrochemical characteristic of phenol and 4-nitrophenol at GCE and successfully realize the electrochemical separation and simultaneous determination of multi-component phenols at GCE without any modification for the first time.
Improving the the Actuation of Polymeric Artificial Muscles Using Magnetically Aligned Polyelectrolytes
Authors: Hasani-Sadrabadi Mohammad Mahdi , Jacob Karl I 
Published: February 2020

Electroactive polymers comprise an emerging class of electromechanical actuators materials that can be used as biomimetic sensors and actuators in wide range of applications from medical devices to robotics applications. Among this class of smart materials, ionic polymer-metal composites (IPMCs) are considered most suitable for artificial muscles since they exhibit a large their large bending motion under relatively low input voltage, flexibility, biocompatibility, and lightweight properties. The polyelectrolytes membrane is a key part of the state-of-the art IPMC devices which act as an ion exchange media to support ionic transport and as a result bending motion of these structures. A recent morphological study of polyelectrolytes confirms the presence of hydrophilic ionic nanochannels that are randomly distributed laterally. These nanochannels are key players to tune the transport properties.
In the current research, we made Nafion/ Imidazole-functionalized superparamagnetic iron oxide nanoparticles (SPIONs) nanocomposite membranes and then by applying external magnetic field we made an induced alignment normal to the membrane’s surface. The effects of the anisotropic dispersion (alignment) of these nanoparticles on phase separation and ionic (H+, Li+, and Na+) conductivity of resulted membranes studied using small angle X-ray scattering (SAXS) and electrochemical impedance spectroscopy (EIS), respectively. Membranes with aligned nanodomains demonstrate higher bending forces as well as faster bending response (tip displacement rate). Due to formation of strong electrostatic interactions between sulfonated groups of Nafion and Imidazole groups at the SPION’s surface these structures display good performance in low humidity conditions as well. Results converge to indicate the effective presence of aligned nanoparticles especially in their functionalized state to tune performance of ionic polymer metal composite. This class of actuators can be applied for wide range of applications with different humidity conditions.
(Nanocarbons Division Richard E. Smalley Research Award) Nanocarbons for Optoelectronic Applications
Authors: Guldi Dirk M. 
Published: February 2020

Carbon is the key to many technological applications that have become indispensable in our daily life. Altering the periodic binding motifs in networks of sp3-, sp2-, and sp-hybridized C-atoms is the conceptual starting point for a wide palette of carbon allotropes. To this end, the past two decades have served as a test-bed for measuring the physico-chemical properties of low-dimensional carbon with the advent of fullerenes (0D), followed in chronological order by carbon nanotubes (1D), carbon nanohorns, and, most recently, by graphene (2D). These species are now poised for use in wide-ranging applications.
Expanding global needs for energy have led to a significant effort to develop alternatives to fossil fuels. While alternative sources for energy are already in use, they comprise a small percentage of the energy demands needed to carry us through the 21st century. No single source will solve the global needs, but the development of photovoltaics has vast potential as a point-of-use power source. Recent work has shown that hybrid photoelectrochemical efforts with a percolation network of photon absorbers coupled to anelectron/hole transporter in combination with advanced photon management are the ideal design for realizing breakthroughs in high photon conversion efficiencies suitable for the catalysis of water.
I will report on our efforts regarding a unifying strategy to use the unprecedented charge transfer chemistry of 0D fullerenes, the ballistic conductance of 1D carbon nanotubes, the semiconducting features of carbon nanohorns, and the high mobility of charge carriers in 2D graphene, together in a groundbreaking approach to solving a far-reaching challenge, that is, the efficient use of the abundant light energy around us.

Leading References:

1) Malig, J. et al. " Toward Multifunctional Wet Chemically Functionalized Graphene – Integration of Oligomeric, Molecular, and Particulate Building Blocks that Reveal Photoactivity and Redox Activity", Acc. Chem. Res.
2013, 46, 53.
2) Guldi, D.M. et al. “Fullerenes For Organic Electronics”, Chem. Soc. Rev.
2009, 38, 1587.
3) Bottari, G. et al. “Covalent and Noncovalent Phthalocyanine-Carbon Nanostructure Systems: Synthesis, Photoinduced Electron Transfer, and Application to Molecular Photovoltaics”, Chem. Rev.
2010, 110, 6768.
(Invited) Graphene Molecules: Synthesis, Electronic Properties and Applications
Authors: Ji Zhiqiang , Doorn Stephen K. , Sykora Milan 
Published: February 2020

Nanographene structures called Graphene Molecules (GMs) have been recently generating a growing interest. Theory predicts that these graphene fragments, comprising fewer than 300 carbon atoms (< 5 nm in size), are subject to quantum confinement effects similar to those observed in inorganic semiconductor quantum dots, but with different scaling laws, excited state properties and effects of functionalization. Predictions of unique size-dependent properties of GMs suggest the possibility that the studies of these structures may yield observation of interesting new phenomena and potentially development of new technologies. However, experimental studies of the electronic structure and demonstration of applications of GMs have so far been limited. This is in part due to challenges associated with the preparation of well-defined structures and in part due to the challenges in applying traditional methods in studies of GMs.
In the first part of my talk I will describe new method for a bottom up synthesis of well-defined GMs on metal oxide surfaces that we recently developed in our laboratory. The method, performed at ambient conditions, yields surface adsorbed GMs structurally and electronically equivalent to those synthesized in solution. The approach reduces the challenges associated with the tendency of GMs to aggregate and provides a convenient path for integration of GMs into optoelectronic applications. In the second part of my talk I will discuss results of our studies of charge transfer properties of GMs with optical band gaps tuned into visible wavelengths, facilitated by the new preparation method. I will show how an electrochemical potential can be used to inject one or more charges into GMs with a high level of control. I will show that the injection of charges leads to dramatic changes in GM absorption properties, quantitatively explain how the two are related and present insights into the kinetics of the charge injection. I will discuss how the basic understanding of the GM charging processes can be effectively exploited in a practical application, such as electrochromic device, wherein the graphene nanostructure is for the first time used as the optically active component. Finally, I will present the results of our studies of GMs as light harvesting components in sensitized solar cells (SSCs). In these studies we have found that mesoscopic TiO2/GM films can be used prepare stable SSCs with efficiencies of η ~1%. I will discuss the limitations and advantages of the GM-based SSC architectures.
(Invited) Tunable Thermoelectric Power Factor in Semiconducting Single-Walled Carbon Nanotube Networks
Authors: Ferguson Andrew , Avery Azure D. , Mistry Kevin S. , Guillot Sarah , Zhou Ben , Blackburn Jeffrey L. , Zink Barry L. , Kim Yong-Hyun 
Published: February 2020

Single-walled carbon nanotubes (SWCNTs) are a versatile electronic material being explored as cost-effective, high-performance active materials in a variety of renewable energy applications such as transparent conducting or light-harvesting layers in photovoltaics and inclusions in thermoelectric composites.
We present a series of experiments focused on understanding the thermoelectric performance of enriched semiconducting SWCNT networks dispersed in a semiconducting polymer matrix. Rational choice of the semiconducting polymer allows us to sensitively tune the s-SWCNT diameter and band gap distributions within the composites. We use a stable charge-transfer dopant to control the density of carriers in the s-SWCNT network, as determined by the bleach of the absorption corresponding to the S11 excitonic transition. The performance of these transparent conducting s-SWCNT composite networks is comparable to neat p-type and n-type s-SWCNT networks doped by either nitric acid or hydrazine treatments. By varying the carrier density we are able to probe the relationship between the electrical conductivity and Seebeck coefficient (thermopower) in the s-SWCNT networks as a function of the carrier density and position of the Fermi energy. Although the electrical conductivity of the s-SWCNT networks is poor at very low carrier densities we have measured a colossal thermopower as high as ~2,500 µV/K, which is more than an order of magnitude larger than has been previously reported for SWCNT-based material systems and is consistent with theoretical calculations that consider the density of electronic states in individual s-SWCNTs. As we tune the carrier density, we are able to maintain a thermopower above 200 µV/K over almost the entire range of hole densities, corresponding to conductivities up to 1885 S/m, resulting in a thermoelectric power factor of ~100 µW/m·K2. These studies suggest that the low dimensionality of the SWCNTs has a stronger impact on the electrical conductivity than the thermopower, implying that they are less strongly coupled in these systems than is observed for compound inorganic semiconductors. These observations demonstrate the ability to exert exquisite control of the thermoelectric performance by tuning the carrier density and/or Fermi energy, and touts SWCNTs as an avenue for realizing thermally stable room temperature thermoelectric devices fashioned from inexpensive and abundant organic constituents.
(Invited) Single-Walled Carbon Nanotubes and Graphene As Highly Efficient Hole Collecting and Transport Layer for Solar Cells
Authors: Maruyama Shigeo , Cui Kehang , Chiba Takaaki , Jeon Il , Chen Xiao , Xiang Rong , Chiashi Shohei , Matsuo Yutaka 
Published: February 2020

We investigate the application of single-walled carbon nanotubes (SWNTs) and graphene as hole extraction and transport layer in various kinds of solar cells including structured SWNTs-Si solar cell [1], dry-deposited SWNTs-Si solar cell [2], graphene-Si solar cells, organic solar cell [3] and perovskite solar cells. Using millimeter-scale monocrystalline single-layer graphene and honeycomb-structured SWNT network, the nanocarbon-Si solar cell demonstrated the air-stable power conversion efficiency (PCE) of 11.6% before any intentional doping process. For organic solar cells (OSC), the SWNT/MoOx/PEDOT:PSS nanocomposite was proposed and developed as hole extracting/electron blocking layer and electrode replacing ITO. Using PTB7/PC71BM mixture as active materials, the PCE of 6% was obtained for on glass substrate and 3.89% on flexible PET substrate. The hole collecting and transport function of SWNTs was also demonstrated in perovskite solar cells with high PCE. We expect that the carbon nanomaterials is very promising in the application solar cells.
References:
[1] K. Cui, T. Chiba, S. Omiya, T. Thurakitseree, P. Zhao, S. Fujii, H. Kataura, E. Einarsson, S. Chiashi, S. Maruyama, J. Phys. Chem. Lett., 4 (2013), 2571.
[2] K. Cui, A. S. Anisimov, T. Chiba, S. Fujii, H. Kataura, A. G. Nasibulin, S. Chiashi, E. I. Kauppinen, S. Maruyama, J. Mater. Chem. A, 2(2014) 11311.
[3] I. Jeon, K. Cui, T. Chiba, A. Anisimov, A. G. Nasibulin, E. I. Kauppinen, S. Maruyama, Y. Matsuo, to be submitted.
(Invited) CdTe Photovoltaic Devices Grown Directly on Transparent Carbon Single Wall Nanotube Back Contacts
Authors: Khanal Rajendra R. , Phillips Adam B. , Song Zhaoning , Xie Yao , Mahabaduge Hasitha P. , Heben Michael J. 
Published: February 2020

CdTe/CdS solar cells were fabricated directly on 25 nm thick carbon single wall nanotube (SWNT) back contacts without the use of copper. Layers were deposited using a commercial, high temperature deposition process, and devices were finished with CdS layers grown by vapor assisted transport and chemical bath deposition. The inclusion of the thin SWNT layer was absolutely essential for good device performance. Device efficiencies were high despite the fact that the SWNT layer was supported on an n-type SnO2 layer that introduced a secondary n/p junction at the rear of the device. The champion device had an efficiency of 7.53%, which is close to the record value of 7.8% for a Cu-free substrate configuration device.[1] The use of a partially transparent back contact allowed comparison of device performance with front and backside illumination, which revealed several novel features of the SWNT back contact.
This work was supported by the U.S. Department of Energy under Award Number DE-SC0006349 and by faculty start-up funds from the University of Toledo. We gratefully acknowledge samples and assistance from Mark D. Dorogi, Syed Zafar, and Gary T. Faykosh of Willard and Kelsey Solar Group.
(1) I. Matulionis, S. Han, J. A. Drayton, K. J. Price, A. D. Compaan, MRS Online Proceedings Library 2001, 668, H8.23.
(Invited) Structured Carbon Nanostructures Derived from Graphene Oxide for Catalysis
Authors: Gupta Gautam 
Published: February 2020

Carbon Nanostructures are at the heart of numerous energy conversion and storage applications including catalysis, fuel cells, super capacitors, and batteries. However, current technologies are marred with issues such as long-term durability under high potentials (e.g., fuel cells), low energy/power density (super capacitors), and metal intercalation issues (batteries). Research efforts worldwide have been focused on developing carbon nanostructures and especially graphene/graphene oxide materials with superior structural and functional properties for fuel cell applications. State-of-the-art devices have typically been synthesized from highly heterogeneous precursors and amorphous carbon materials. Catalysts derived from graphene and graphene-oxide (GO) are more homogeneous and possess properties, such as good chemical stability, excellent conductivity, and more importantly, can be functionalized in a controlled manner. These unique properties have led to explosion in research in areas of graphitic materials as catalyst support/material for ORR.
In this study, we report the synthesis of highly ordered carbon nanostructures derived from GO. Despite the widely known fact of the presence of residual water between the graphene oxide layers, only a few reports exist about the role of intercalated water. We control the density of functional groups and inter-lamellar spacing of GO materials using low temperature drying treatments. The synthesized graphene oxide structures were subjected to reduction and nitrogen doping in different conditions to obtain an optimum oxygen reduction reaction catalyst. In this report, we focus on the affect of pre-treatment on the structure and function of the catalyst systems. We further demonstrate that the structure formed following the effective removal of intercalated water is crucial in the formation of active sites due to nano-confinement of water. Towards the end, we demonstrate a systematic shift in half wave potential and a significant decrease in peroxide production obtained depending upon the graphene oxide pretreatment.

Acknowledgment

Financial support from the Los Alamos National Laboratory Laboratory-Directed Research and Development (LDRD) Program is gratefully acknowledged.
(Keynote) Paper-Based Lateral Flow Strips Toward Point-of-Care Detection of Biomolecules
Authors: Wu Nick , Zheng Peng , Gao Xuefei 
Published: February 2020

This talk shows our effort to develop the paper-based lateral flow strips as point-of-care devices. The detection platforms based on different signal transduction mechanisms have been developed. The detection platforms have then been integrated into the paper-based membrane to form the lateral flow strips. The paper-based lateral flow strips are inexpensive, require only a hundred of micro-liter sample and minimize the sample pre-treatment in the lab setting.
A Fully Inkjet-Printed Carbon Nanotube Electrochemical Sensor on Paper
Authors: da Costa Tallis H. , Tortorich Ryan P. , Song Edward , Choi Jin-Woo 
Published: February 2020

We present a fully inkjet-printed electrochemical sensor on paper, which uses inkjet-printed carbon nanotubes as the working, counter, and reference electrodes. Although paper-based electrochemical sensors have been demonstrated previously, our method of fabrication is both faster and cheaper and fully inkjet-printed. Due to its superior patterning ability, inkjet printing allows for the fabrication of on-demand paper-based electrochemical sensors without the use of templates or post-deposition photolithography. Additionally, in combining inkjet printing with an exciting material like carbon nanotubes rather than common metals (i.e. gold and silver), the fabrication cost is further reduced, and the possibility for mechanically flexible sensors becomes a reality.
The use of paper as a substrate offers many advantages over other possible rigid substrates as well as flexible polymer substrates. Of course, paper is indeed a renewable resource and thus is a very cost-effective substrate for fabrication of disposable sensors. Additionally, paper is naturally flexible, preventing damage to the sensor upon external stress during use. Finally, paper is a great candidate for microfluidic applications due to its superb ability to transport liquids.
The fabrication process is remarkably simple. The electrode design was developed using any drawing software or CAD. Multi-walled carbon nanotubes (MWCNTs) were dispersed in deionized (DI) water using sodium dodecyl sulfate (SDS), an anionic surfactant. More specifically, a bottle containing 10 mg/ml of MWCNTs and 8 mg/ml of SDS was sonicated for 30 minutes and centrifuged at 12,000 rpm for 5 minutes. The carbon nanotube ink was then injected into a clean ink cartridge and printed using an office inkjet printer.
In order to ensure proper functionality, a low electrode resistance was necessary. This was achieved by printing the carbon nanotube ink multiple times to reduce the sheet resistance. We were able to achieve less than 2 k-ohm/square with 20 prints on paper. The sensor was tested with various concentrations of FeSO4 in 0.1 M H2SO4. A simple potentiostat circuit was used along with a LabView FieldPoint module for voltage control and current measurement. Potential step voltammetry was employed and the saturation current was used as a means to determine analyte concentration.