Extended Abstract Nanostructure is the prerequisite to obtain an appropriate surface roughness for the superhydrophobicity or oleophobicity. Synthetic surfaces with nano-sized bumps have been recently developed based on low-energy surface and multiscale roughness by various nanotechniques [1]. Especially, antifouling, deicing, antibacterial, and self-cleaning surfaces are important for improving the energy efficiency of building, automobile, medical devices, and household care [2]. During the past two decades, superhydrophobic nanostructures and nanocoatings that are inspired by the lotus-leafs effect have been extensively studied. However, studies on the oloephobic surfaces were paid less attention. Therefore, it is a challenge to create functional surfaces which completely resist wetting not only by water, but also by organic liquids such as oils [3]. In this work, a study on fabrication and characterization of oleophobic (repellent to oil) surface using thermal imprint lithography is conducted. For thermal imprinting process, a nickel (Ni) stamp with pillar-array was fabricated. During the imprint lithography, the PMMA (polymethyl methacrylate) substrate was prepared and heated above the glass transition temperature. As a result, the micro-patterned PMMA sheet was successfully formed [Fig. 1]. By application of fluoride coating (DURASURF, HARVES. Co.) and polymer nano-particles stacking on the micro-patterned PMMA sheet, a surface modification was carried out. Thus, the hierarchical complex surfaces which have superhydrophobic and oleophobic properties with complex nano-particles on micro-patterns were created. This hierarchical structure played an important role in oil-repellent properties. As a result, the imprinted surface from nickel stamp showed contact angle around 150° for water and 118° for hexadecane. This method can be applicable for a variety of applications such as self-cleaning, antifouling, and antifrosting. Furthermore, we will discuss the mechanism of creating an oleophobic coating in details.
{"title":"Characterization of Oleophobic Functional Surfaces Fabricated by Thermal Imprinting Process","authors":"Kwang-Jin Bae, W. Yao, Y. Cho","doi":"10.11159/ICNNFC17.109","DOIUrl":"https://doi.org/10.11159/ICNNFC17.109","url":null,"abstract":"Extended Abstract Nanostructure is the prerequisite to obtain an appropriate surface roughness for the superhydrophobicity or oleophobicity. Synthetic surfaces with nano-sized bumps have been recently developed based on low-energy surface and multiscale roughness by various nanotechniques [1]. Especially, antifouling, deicing, antibacterial, and self-cleaning surfaces are important for improving the energy efficiency of building, automobile, medical devices, and household care [2]. During the past two decades, superhydrophobic nanostructures and nanocoatings that are inspired by the lotus-leafs effect have been extensively studied. However, studies on the oloephobic surfaces were paid less attention. Therefore, it is a challenge to create functional surfaces which completely resist wetting not only by water, but also by organic liquids such as oils [3]. In this work, a study on fabrication and characterization of oleophobic (repellent to oil) surface using thermal imprint lithography is conducted. For thermal imprinting process, a nickel (Ni) stamp with pillar-array was fabricated. During the imprint lithography, the PMMA (polymethyl methacrylate) substrate was prepared and heated above the glass transition temperature. As a result, the micro-patterned PMMA sheet was successfully formed [Fig. 1]. By application of fluoride coating (DURASURF, HARVES. Co.) and polymer nano-particles stacking on the micro-patterned PMMA sheet, a surface modification was carried out. Thus, the hierarchical complex surfaces which have superhydrophobic and oleophobic properties with complex nano-particles on micro-patterns were created. This hierarchical structure played an important role in oil-repellent properties. As a result, the imprinted surface from nickel stamp showed contact angle around 150° for water and 118° for hexadecane. This method can be applicable for a variety of applications such as self-cleaning, antifouling, and antifrosting. Furthermore, we will discuss the mechanism of creating an oleophobic coating in details.","PeriodicalId":31009,"journal":{"name":"RAN","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82874097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ByoungChang Kim, Tae-Hyung Kim, Sun-Hye Kim, Changkyu Kim, Hyungsuk Lee
Extended Abstract Polymer nanofiber composites for the treatment of hazardous compounds are of considerable scientific and technological interest. In this study, polyamide nanofiber for organic pollutant removal and chemical warfare protection is discussed. The effect of position of functional materials in nanofiber matrix on the photocatalytic activity was studied by comparing the AgTiO2-decorated nylon nanofiber composite (AT-sur-NF) and Ag-TiO2-embedded nylon nanofiber composite (AT-in-NF) [1]. We find that AT-sur-NF shows better photocatalytic activity compared to the photocatalytic activity of AT-in-NF. Based on these results, nylon and meta-aramid nanofibers decorated by various functional nanomaterials were fabricated. The electrospun meta-aramid nanofiber composites exhibit poor chemical stability because of the salt molecules remaining between meta-aramid chains [2]. The chemical stability of meta-aramid nanofiber composites were improved by removing salt molecules during washing and additional thermal treatment. The polyamide nanofiber composites were stacked to enhance mechanical properties and resistivity to chemical warfare agents (CWAs). By controlling the stacking of polyamide nanofiber composites, thickness, weight density, and cool/warm feeling are optimized. In addition, the assemblies exhibit enough resistivity to CWAs while still maintain water vapor transmission to allow evaporation of sweat on the skin. Further study on the thermal properties and microstructure of nylon nanofibers reveals that the chains rigidity and thermal stability increase with decreasing diameter of nylon nanofibers.
{"title":"White Light Scanning Interferometry for Nano Surface Metrology","authors":"ByoungChang Kim, Tae-Hyung Kim, Sun-Hye Kim, Changkyu Kim, Hyungsuk Lee","doi":"10.11159/icnei17.102","DOIUrl":"https://doi.org/10.11159/icnei17.102","url":null,"abstract":"Extended Abstract Polymer nanofiber composites for the treatment of hazardous compounds are of considerable scientific and technological interest. In this study, polyamide nanofiber for organic pollutant removal and chemical warfare protection is discussed. The effect of position of functional materials in nanofiber matrix on the photocatalytic activity was studied by comparing the AgTiO2-decorated nylon nanofiber composite (AT-sur-NF) and Ag-TiO2-embedded nylon nanofiber composite (AT-in-NF) [1]. We find that AT-sur-NF shows better photocatalytic activity compared to the photocatalytic activity of AT-in-NF. Based on these results, nylon and meta-aramid nanofibers decorated by various functional nanomaterials were fabricated. The electrospun meta-aramid nanofiber composites exhibit poor chemical stability because of the salt molecules remaining between meta-aramid chains [2]. The chemical stability of meta-aramid nanofiber composites were improved by removing salt molecules during washing and additional thermal treatment. The polyamide nanofiber composites were stacked to enhance mechanical properties and resistivity to chemical warfare agents (CWAs). By controlling the stacking of polyamide nanofiber composites, thickness, weight density, and cool/warm feeling are optimized. In addition, the assemblies exhibit enough resistivity to CWAs while still maintain water vapor transmission to allow evaporation of sweat on the skin. Further study on the thermal properties and microstructure of nylon nanofibers reveals that the chains rigidity and thermal stability increase with decreasing diameter of nylon nanofibers.","PeriodicalId":31009,"journal":{"name":"RAN","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89791973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
O. Walter, K. Popa, L. Balice, O. D. Blanco, P. Raison, L. Martel, M. Naji, M. Cologna
{"title":"AnO2 Nanocrystals via Hydrothermal Decomposition of Actinide Oxalates","authors":"O. Walter, K. Popa, L. Balice, O. D. Blanco, P. Raison, L. Martel, M. Naji, M. Cologna","doi":"10.11159/ICNNFC17.142","DOIUrl":"https://doi.org/10.11159/ICNNFC17.142","url":null,"abstract":"","PeriodicalId":31009,"journal":{"name":"RAN","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73167500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Low-Cost, Energy-Saving Plasma Method for Preparation of Inorganic Submicron Fibers","authors":"V. Medvecká, D. Kováčik, A. Zahoranová, M. Černák","doi":"10.11159/ICNNFC17.131","DOIUrl":"https://doi.org/10.11159/ICNNFC17.131","url":null,"abstract":"","PeriodicalId":31009,"journal":{"name":"RAN","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86004892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Extended Abstract Gold is very stable in biochemical environments and can immobilize easily bioactive molecules including DNAs, aptamers, antibodies, and peptides through Au-S bonding. In addition, gold is an excellent plasmonic material and has been widely used for fabrication of sensitive sensors. However, intrinsic surface defects of gold, such as step, terrace, vacancy, and grain boundary, are major problems for perfect immobilization of the biochemical molecules.[1] So, top-down polishing including thermal annealing, UV-ozone cleaning, and hydroxyl radical etching has been employed to reduce the surface defects, but being hardly possible to eliminate them completely.[2] On the other hand, Au nanoplates synthesized in vapor phase have atomically smooth surfaces without any surface defects, being able to construct a highly well-ordered bio-molecular layer from coherently linked metal-molecule interface. Highly-selective detection of anti-cyclic citrullinated peptides (anti-CCPs) has been an important issue to diagnose early rheumatoid arthritis (RA). Anti-CCP is a highly specific biomarker (90%-95%) for RA, being in a very small quantity at early RA which does not show clinical symptoms.[3] Since it takes several months or even years to be characterized as RA from the chronic inflammation occurred at the synovial joints, the sensitivity is more important than detection time to identify the RA patients in early-stage. However, current sensors based on enzyme-linked immunosorbent assay (ELISA) methods have been focused on rapid detection of anti-CCPs. Recently, Dubacheva et al. reported super-selective targeting employing a well-defined self-assembled monolayer (SAM) formed on UV-ozone treated gold surface.[4] Because non-specific binding can cause false-positive signals and increase the zero-signal intensity, it is a key-factor which reduces the sensor’s sensitivity. Therefore, super-selective detection of the anti-CCPs by a well-defined CCP layer would play an important role in diagnosis of early RA. Surface-Enhanced Raman Scattering (SERS) sensors employing hot spots by nanoscale gap between noble metal nanostructures have been much attention because of single molecule level sensitivity.[5] Here, we report that anti-CCP SERS sensor fabricated with ultraflat, ultraclean, and single-crystalline Au nanoplate can detect even 40 aM (0.1 pg/ml) of anti-CCPs due to highly reduced nonspecific bindings as 50 times compared to commercial Au film. The well-ordered CCPs on Au nanoplates can clearly increase target signals and decrease zero-signals, being able to improve the sensitivity as 100 times than current SERS sensor. Furthermore, atomic force microscopy (AFM) studies in dry ambient environment show distinctly the super-sensitive CCPactive surfaces formed on the Au nanoplate. Thus, we expect that ultraflat Au nanoplate SERS sensors enable attomolar detection of anti-CCPs and will be utilized excellently for early-diagnosis of RA.
金在生物化学环境中非常稳定，可以通过Au-S键很容易地固定生物活性分子，包括dna、适体、抗体和肽。此外，金是一种优良的等离子体材料，已广泛用于制造敏感传感器。然而，金的内在表面缺陷，如台阶、台阶、空位和晶界，是实现生化分子完美固定化的主要问题。[1]因此，自上而下的抛光包括热退火、uv -臭氧清洗和羟基自由基蚀刻已被用于减少表面缺陷，但几乎不可能完全消除它们。[2]另一方面，在气相合成的金纳米片具有原子光滑的表面，没有任何表面缺陷，能够通过金属-分子界面的相干连接构建高度有序的生物分子层。高选择性检测抗环瓜氨酸肽(anti- ccp)已成为诊断早期类风湿关节炎(RA)的重要问题。Anti-CCP是一种高度特异性的RA生物标志物(90%-95%)，在RA早期不表现临床症状时含量极低。[3]由于滑膜关节的慢性炎症需要数月甚至数年才能被诊断为RA，因此在早期识别RA患者时，灵敏度比检测时间更重要。然而，目前基于酶联免疫吸附测定(ELISA)方法的传感器主要集中在抗ccp的快速检测上。最近，Dubacheva等人报道了在uv -臭氧处理的金表面上形成的定义良好的自组装单层(SAM)的超选择性靶向。[4]非特异性结合会产生假阳性信号，增加零信号强度，是降低传感器灵敏度的关键因素。因此，通过明确的CCP层超选择性检测anti-CCP在早期RA的诊断中将发挥重要作用。表面增强拉曼散射(SERS)传感器由于其单分子水平的灵敏度而受到广泛关注。[5]在这里，我们报告了用超扁平、超净和单晶金纳米板制成的抗ccp SERS传感器，由于非特异性结合高度减少，与商业金膜相比，甚至可以检测到40 aM (0.1 pg/ml)的抗ccp。在金纳米片上有序排列的ccp可以明显增加目标信号，减少零信号，比现有SERS传感器的灵敏度提高100倍。此外，原子力显微镜(AFM)研究表明，在干燥环境下，金纳米板上形成了超灵敏的ccactive表面。因此，我们期望超扁平金纳米板SERS传感器能够实现抗ccp的原子摩尔检测，并将很好地用于RA的早期诊断。
{"title":"Ultraflat, Ultraclean Au Nanoplate for Supersenstive Detection of Anti-CCPs","authors":"Eungwang Kim, H. Lee, Bongsoo Kim","doi":"10.11159/ICNB17.113","DOIUrl":"https://doi.org/10.11159/ICNB17.113","url":null,"abstract":"Extended Abstract Gold is very stable in biochemical environments and can immobilize easily bioactive molecules including DNAs, aptamers, antibodies, and peptides through Au-S bonding. In addition, gold is an excellent plasmonic material and has been widely used for fabrication of sensitive sensors. However, intrinsic surface defects of gold, such as step, terrace, vacancy, and grain boundary, are major problems for perfect immobilization of the biochemical molecules.[1] So, top-down polishing including thermal annealing, UV-ozone cleaning, and hydroxyl radical etching has been employed to reduce the surface defects, but being hardly possible to eliminate them completely.[2] On the other hand, Au nanoplates synthesized in vapor phase have atomically smooth surfaces without any surface defects, being able to construct a highly well-ordered bio-molecular layer from coherently linked metal-molecule interface. Highly-selective detection of anti-cyclic citrullinated peptides (anti-CCPs) has been an important issue to diagnose early rheumatoid arthritis (RA). Anti-CCP is a highly specific biomarker (90%-95%) for RA, being in a very small quantity at early RA which does not show clinical symptoms.[3] Since it takes several months or even years to be characterized as RA from the chronic inflammation occurred at the synovial joints, the sensitivity is more important than detection time to identify the RA patients in early-stage. However, current sensors based on enzyme-linked immunosorbent assay (ELISA) methods have been focused on rapid detection of anti-CCPs. Recently, Dubacheva et al. reported super-selective targeting employing a well-defined self-assembled monolayer (SAM) formed on UV-ozone treated gold surface.[4] Because non-specific binding can cause false-positive signals and increase the zero-signal intensity, it is a key-factor which reduces the sensor’s sensitivity. Therefore, super-selective detection of the anti-CCPs by a well-defined CCP layer would play an important role in diagnosis of early RA. Surface-Enhanced Raman Scattering (SERS) sensors employing hot spots by nanoscale gap between noble metal nanostructures have been much attention because of single molecule level sensitivity.[5] Here, we report that anti-CCP SERS sensor fabricated with ultraflat, ultraclean, and single-crystalline Au nanoplate can detect even 40 aM (0.1 pg/ml) of anti-CCPs due to highly reduced nonspecific bindings as 50 times compared to commercial Au film. The well-ordered CCPs on Au nanoplates can clearly increase target signals and decrease zero-signals, being able to improve the sensitivity as 100 times than current SERS sensor. Furthermore, atomic force microscopy (AFM) studies in dry ambient environment show distinctly the super-sensitive CCPactive surfaces formed on the Au nanoplate. Thus, we expect that ultraflat Au nanoplate SERS sensors enable attomolar detection of anti-CCPs and will be utilized excellently for early-diagnosis of RA.","PeriodicalId":31009,"journal":{"name":"RAN","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82951066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Mucoadhesive Pectin-Based Cross-Linked Microgels","authors":"Dmitrii A. Tolstykh, K. Kozhikhova, M. Mironov","doi":"10.11159/nddte17.113","DOIUrl":"https://doi.org/10.11159/nddte17.113","url":null,"abstract":",","PeriodicalId":31009,"journal":{"name":"RAN","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87669247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. G. Lui, Joycelyn Wüstehube-Lausch, Hans-Ulrich Schmoldt, Matin Daneschdar, U. Şahin
Extended Abstract Protein scaffolds are a new generation of affinity proteins specialized to complement the antibody and antibody derivatives for therapeutic and diagnostic applications [1]. Cystine-knot miniproteins (Microbodies) represent an alternative protein scaffold with certain drug-desired properties such as high target affinity and specificity, in particular stability, solubility and pharmacokinetic behavior of the binding protein [2, 3]. Additionally this small peptidic molecule with a simple architecture facilitates an easy straight-forward chemical production and the construction of multi-functional fusion molecules [4]. Site-directed conjugation of a cystine-knot miniprotein with a radionuclide already showed specific targeting of U87MG tumor-bearing mice [5]. Tumor specific uptake of an imaging agent offers a promising benefit for in vivo visualization to facilitate surgically cancer removal as well as cancer staging [4]. All in all cystine-knot miniproteins is an ideally suitable scaffold for in vivo diagnostic imaging tools. Moreover this protein can be used as scaffold for delivery of therapeutic payloads and functionalized nanoparticle drugs [4, 6]. Microbody owing a remarkable stability and an extraordinary tolerance to sequence variation, which enables the construction of combinatorial libraries [7]. Based on an open chain variant of the squash trypsin inhibitor MCoTI-II found in gac fruit (Momordica cochinchinensis) combinatorial phage libraries was designed to allow the identification of high affine binders against respective target proteins [8, 9]. The phage display technique provides a powerful tool for the screening of variants in a high throughput manner to select protein-protein interacting binders [10]. In this work three novel Microbody phage libraries with certain randomized amino acids in defined loop positions could be successfully generated. The analysis of those generated libraries on phage level indicated the functional surface presentation of Microbodies. Furthermore the development of a cell-based screening process enables the targeting of membrane embedded proteins in their native conformation. For Microbody-based applications plasma membrane proteins or extracellular located proteins can be addressed. Based on mRNA expression data a transmembrane cell adhesion protein was selected as a non-small cell lung cancer associated target protein. The target is substantially expressed on lung squamous cancer and shows only minimal background expression in thoracic region of healthy tissues. In order to validate the candidate as a NSCLC associated target on protein level, western blot analysis with lung cancer patient tissues were performed. A correlation of mRNA expression data and protein expression analysis could be observed and confirmed the upregulation in NSCLC patient samples. Currently, different cell-based screening experiments of Microbody phage libraries against the target are performed in order to identify
{"title":"Process Development for the Identification of Novel Microbodies against NSCLC Related Targets","authors":"B. G. Lui, Joycelyn Wüstehube-Lausch, Hans-Ulrich Schmoldt, Matin Daneschdar, U. Şahin","doi":"10.11159/NDDTE17.117","DOIUrl":"https://doi.org/10.11159/NDDTE17.117","url":null,"abstract":"Extended Abstract Protein scaffolds are a new generation of affinity proteins specialized to complement the antibody and antibody derivatives for therapeutic and diagnostic applications [1]. Cystine-knot miniproteins (Microbodies) represent an alternative protein scaffold with certain drug-desired properties such as high target affinity and specificity, in particular stability, solubility and pharmacokinetic behavior of the binding protein [2, 3]. Additionally this small peptidic molecule with a simple architecture facilitates an easy straight-forward chemical production and the construction of multi-functional fusion molecules [4]. Site-directed conjugation of a cystine-knot miniprotein with a radionuclide already showed specific targeting of U87MG tumor-bearing mice [5]. Tumor specific uptake of an imaging agent offers a promising benefit for in vivo visualization to facilitate surgically cancer removal as well as cancer staging [4]. All in all cystine-knot miniproteins is an ideally suitable scaffold for in vivo diagnostic imaging tools. Moreover this protein can be used as scaffold for delivery of therapeutic payloads and functionalized nanoparticle drugs [4, 6]. Microbody owing a remarkable stability and an extraordinary tolerance to sequence variation, which enables the construction of combinatorial libraries [7]. Based on an open chain variant of the squash trypsin inhibitor MCoTI-II found in gac fruit (Momordica cochinchinensis) combinatorial phage libraries was designed to allow the identification of high affine binders against respective target proteins [8, 9]. The phage display technique provides a powerful tool for the screening of variants in a high throughput manner to select protein-protein interacting binders [10]. In this work three novel Microbody phage libraries with certain randomized amino acids in defined loop positions could be successfully generated. The analysis of those generated libraries on phage level indicated the functional surface presentation of Microbodies. Furthermore the development of a cell-based screening process enables the targeting of membrane embedded proteins in their native conformation. For Microbody-based applications plasma membrane proteins or extracellular located proteins can be addressed. Based on mRNA expression data a transmembrane cell adhesion protein was selected as a non-small cell lung cancer associated target protein. The target is substantially expressed on lung squamous cancer and shows only minimal background expression in thoracic region of healthy tissues. In order to validate the candidate as a NSCLC associated target on protein level, western blot analysis with lung cancer patient tissues were performed. A correlation of mRNA expression data and protein expression analysis could be observed and confirmed the upregulation in NSCLC patient samples. Currently, different cell-based screening experiments of Microbody phage libraries against the target are performed in order to identify","PeriodicalId":31009,"journal":{"name":"RAN","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83540672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sudhanshu Shukla, T. Sritharan, Xiong Qihua, T. Sum, G. Xing, Nripan, Mathews, Hu Ge, T. Venkatesan, S. Mathew, Zhenghua Su, V. Nalla
Successful extraction of photo excited carriers from a photo active material is key towards a successful PV device. The high losses exhibited by a device with pyrite as the active layer has been noted previously but never investigated systematically to understand the photo physics and the carrier loss mechanisms to improve its performance. Here we report a detailed characterization of a film made using {100} terminated, pure pyrite single crystal nano cubes. Using ultrafast transient absorption spectroscopy we found fast carrier localization of photo excited carriers to indirect band edge and shallow trap states with characteristic decay time of 1.8 picoseconds, followed by relaxation to deep states and recombination of trapped carriers with long characteristic decay times of 50-990 nanoseconds. Its optical absorption characteristics correlate to a disordered semiconductor. Temperature dependent electrical resistivity exhibits a Mott variable range hopping (VRH) type conduction mechanism consistent with the presence of high density of defect states. An electron band model with midgap defect states is formulated that could explain all the observed phenomena.
{"title":"Investigation of Photocarrier Losses in Pyrite (FeS2) Film Consisting Single Crystal Nanocubes","authors":"Sudhanshu Shukla, T. Sritharan, Xiong Qihua, T. Sum, G. Xing, Nripan, Mathews, Hu Ge, T. Venkatesan, S. Mathew, Zhenghua Su, V. Nalla","doi":"10.11159/ICNNFC17.118","DOIUrl":"https://doi.org/10.11159/ICNNFC17.118","url":null,"abstract":"Successful extraction of photo excited carriers from a photo active material is key towards a successful PV device. The high losses exhibited by a device with pyrite as the active layer has been noted previously but never investigated systematically to understand the photo physics and the carrier loss mechanisms to improve its performance. Here we report a detailed characterization of a film made using {100} terminated, pure pyrite single crystal nano cubes. Using ultrafast transient absorption spectroscopy we found fast carrier localization of photo excited carriers to indirect band edge and shallow trap states with characteristic decay time of 1.8 picoseconds, followed by relaxation to deep states and recombination of trapped carriers with long characteristic decay times of 50-990 nanoseconds. Its optical absorption characteristics correlate to a disordered semiconductor. Temperature dependent electrical resistivity exhibits a Mott variable range hopping (VRH) type conduction mechanism consistent with the presence of high density of defect states. An electron band model with midgap defect states is formulated that could explain all the observed phenomena.","PeriodicalId":31009,"journal":{"name":"RAN","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88950175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Extended Abstract Nanocrystalline ceramics have great potential for applications in electronics, sensors and energy-related areas due to their remarkable functional properties. However, only doped, co-doped and binary ceramics have been extensively studied, while the area of equimolar, multicomponent ceramics has been a largely unexplored field until recently [1]–[3]. In this investigation, a multicomponent nanocrystalline ceramic oxide, (Co,Cu,Mg,Ni,Zn)O, was synthesised with the primary intention of studying the type and stability of the phases formed with systematically varying zinc oxide content. The individual components were selected on the basis of Pauling’s rules in order to maximise the probability of single phase formation. All these elements have a +2 oxidation state in their stable oxide form. While the oxides of cobalt, magnesium and nickel have a stable rocksalt crystal structure, zinc oxide stabilizes in the wurzite structure and copper has a stable monoclinic structure (a distorted rocksalt structure, due to the Jahn-Teller effect). Therefore, it could be expected that copper and zinc would distribute themselves in the stable lattice structure of the other rocksalt oxides and form a solid solution within the 5 component system, even though it has been reported that in the binary (Ni,Cu)O system, the dominant Jahn-Teller effect leads to the formation of a distorted cubic structure [4]. Based on this premise, a bottom-up, nebulised spray pyrolysis (NSP) approach was selected for synthesis. NSP is a relatively rapid process with adequate residence time which yields clean and stable equilibrium (or near-equilibrium) phases of the product. The process is also industrially scalable. Nitrates of the selected cations were used as precursors and the individual precursor quantities were adjusted in order to maintain the requisite final compositions with de-ionised water as the solvent. X-ray diffraction (XRD) of the as-synthesized powders confirmed the presence of single phase cubic rocksalt structure in the fm3̅m space group for all the compositions. The variation of the synthesis temperature shows a decreasing trend from 1400 C to 1100 C for uniform increase in the concentration of ZnO from 4% to equimolar composition because of increasing configurational entropy towards equimolar concentrations. This observation could be also due to the decrease in Jahn-Teller effect with decrease in CuO concentration. The crystallite size calculated using Scherrer formula shows a decrease from 48 nm for 4% ZnO to 20 nm for 20% ZnO in a linear fashion since ZnO has a different crystal structure, necessitating more energy requirement to dissolve ZnO in rocksalt lattice leaving lesser energy for crystallite growth. Also with increasing ZnO concentration, its dissimilar crystal structure hinders the diffusion of isostructured components leading to lesser crystallite growth.[5]. Scanning electron microscopy (SEM) revealed the particles to have broken shell l
{"title":"Phase Evolution During Synthesis of Nanocrystalline Multicomponent (Co,Cu,Mg,Ni,Zn)O Metal Oxides with Varying ZnO Content","authors":"N. Usharani, R. N. Kumar, S. Bhattacharya","doi":"10.11159/ICNNFC17.143","DOIUrl":"https://doi.org/10.11159/ICNNFC17.143","url":null,"abstract":"Extended Abstract Nanocrystalline ceramics have great potential for applications in electronics, sensors and energy-related areas due to their remarkable functional properties. However, only doped, co-doped and binary ceramics have been extensively studied, while the area of equimolar, multicomponent ceramics has been a largely unexplored field until recently [1]–[3]. In this investigation, a multicomponent nanocrystalline ceramic oxide, (Co,Cu,Mg,Ni,Zn)O, was synthesised with the primary intention of studying the type and stability of the phases formed with systematically varying zinc oxide content. The individual components were selected on the basis of Pauling’s rules in order to maximise the probability of single phase formation. All these elements have a +2 oxidation state in their stable oxide form. While the oxides of cobalt, magnesium and nickel have a stable rocksalt crystal structure, zinc oxide stabilizes in the wurzite structure and copper has a stable monoclinic structure (a distorted rocksalt structure, due to the Jahn-Teller effect). Therefore, it could be expected that copper and zinc would distribute themselves in the stable lattice structure of the other rocksalt oxides and form a solid solution within the 5 component system, even though it has been reported that in the binary (Ni,Cu)O system, the dominant Jahn-Teller effect leads to the formation of a distorted cubic structure [4]. Based on this premise, a bottom-up, nebulised spray pyrolysis (NSP) approach was selected for synthesis. NSP is a relatively rapid process with adequate residence time which yields clean and stable equilibrium (or near-equilibrium) phases of the product. The process is also industrially scalable. Nitrates of the selected cations were used as precursors and the individual precursor quantities were adjusted in order to maintain the requisite final compositions with de-ionised water as the solvent. X-ray diffraction (XRD) of the as-synthesized powders confirmed the presence of single phase cubic rocksalt structure in the fm3̅m space group for all the compositions. The variation of the synthesis temperature shows a decreasing trend from 1400 C to 1100 C for uniform increase in the concentration of ZnO from 4% to equimolar composition because of increasing configurational entropy towards equimolar concentrations. This observation could be also due to the decrease in Jahn-Teller effect with decrease in CuO concentration. The crystallite size calculated using Scherrer formula shows a decrease from 48 nm for 4% ZnO to 20 nm for 20% ZnO in a linear fashion since ZnO has a different crystal structure, necessitating more energy requirement to dissolve ZnO in rocksalt lattice leaving lesser energy for crystallite growth. Also with increasing ZnO concentration, its dissimilar crystal structure hinders the diffusion of isostructured components leading to lesser crystallite growth.[5]. Scanning electron microscopy (SEM) revealed the particles to have broken shell l","PeriodicalId":31009,"journal":{"name":"RAN","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75250764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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