Pub Date : 2021-11-30DOI: 10.1088/2399-1984/ac3ec1
X. Lei, Bo Liu, Payam Ahmadian Koudakan, Hongge Pan, Yitai Qian, Gongming Wang
Recently, single-atom catalysts (SACs) have been found to be promising candidates for oxygen electrocatalysis in rechargeable lithium–oxygen batteries (LOBs) owing to their high oxygen electrocatalytic activity and high stability, which originates from their unique coordination environments and electronic properties. As a new type of catalyst for LOBs, the advancements have never been reviewed and discussed comprehensively. Herein, breakthroughs in the design of various types of SACs as cathode catalysts for LOBs are summarized, including Co-based, Ru-based, and other types of SACs. Moreover, considerable emphasis is placed on the correlations between the structural feature of the SAC active sites and the electrocatalytic performance of LOBs. Finally, an overview and challenges of SACs for practical LOBs are also provided. This review provides an intensive understanding of SACs for designing efficient oxygen electrocatalysis and offers useful guidelines for the development of SACs in the field of LOBs.
{"title":"Single-atom catalyst cathodes for lithium–oxygen batteries: a review","authors":"X. Lei, Bo Liu, Payam Ahmadian Koudakan, Hongge Pan, Yitai Qian, Gongming Wang","doi":"10.1088/2399-1984/ac3ec1","DOIUrl":"https://doi.org/10.1088/2399-1984/ac3ec1","url":null,"abstract":"Recently, single-atom catalysts (SACs) have been found to be promising candidates for oxygen electrocatalysis in rechargeable lithium–oxygen batteries (LOBs) owing to their high oxygen electrocatalytic activity and high stability, which originates from their unique coordination environments and electronic properties. As a new type of catalyst for LOBs, the advancements have never been reviewed and discussed comprehensively. Herein, breakthroughs in the design of various types of SACs as cathode catalysts for LOBs are summarized, including Co-based, Ru-based, and other types of SACs. Moreover, considerable emphasis is placed on the correlations between the structural feature of the SAC active sites and the electrocatalytic performance of LOBs. Finally, an overview and challenges of SACs for practical LOBs are also provided. This review provides an intensive understanding of SACs for designing efficient oxygen electrocatalysis and offers useful guidelines for the development of SACs in the field of LOBs.","PeriodicalId":54222,"journal":{"name":"Nano Futures","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2021-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46627499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-25DOI: 10.1088/2399-1984/ac3d6e
Molood Barmala, M. Behnood
In this work we present the preparation of novel ternary metal oxide nanoparticles, La2Cu0.8Zn0.2O4 (LCZO), using a simple co-precipitation method. The crystalline structure, morphology and composition of the prepared LCZO nanoparticles were characterized by x-ray diffraction, scanning electron microscopy and energy-dispersive x-ray analysis. The diffuse reflectance spectrum investigation showed that LCZO nanoparticles have considerable light absorption in the visible light region. Also, the LCZO nanoparticles possess a band-gap energy of 2.82 eV. To investigate the visible light photocatalytic potential of the prepared LCZO nanoparticles, two photocatalytic reactions were conducted, namely degradation of methylene blue (MB) solution and desulfurization of dibenzothiophene (DBT). In the presence of a 3:1 molar ratio of H2O2/DBT, a high photocatalytic desulfurization rate of DBT (93.7%) was obtained over 0.2 g of LCZO photocatalyst. In addition, the photocatalytic degradation rate of MB solution was 91.4%. The mechanisms of both photocatalytic reactions were studied using different radical scavenging agents, which showed that hydroxyl radicals are responsible for highly efficient desulfurization and degradation reactions. Moreover, reusability experiments reveal that the prepared LCZO photocatalyst has great stability and recyclability for both desulfurization of DBT and degradation of MB after six reaction cycles.
本文采用简单共沉淀法制备了新型三元金属氧化物纳米粒子la2cu0.8 zn0.2 2o4 (LCZO)。采用x射线衍射、扫描电镜和能量色散x射线分析对制备的LCZO纳米颗粒的晶体结构、形貌和组成进行了表征。漫反射光谱研究表明，LCZO纳米颗粒在可见光区有相当大的光吸收。此外，LCZO纳米颗粒具有2.82 eV的带隙能量。为了考察所制备的LCZO纳米颗粒的可见光催化性能，进行了亚甲基蓝(MB)溶液降解和二苯并噻吩(DBT)脱硫两种光催化反应。在H2O2/DBT摩尔比为3:1的条件下，0.2 g LCZO光催化剂对DBT的光催化脱硫率高达93.7%。此外，光催化对MB溶液的降解率为91.4%。用不同的自由基清除剂对两种光催化反应的机理进行了研究，结果表明，羟基自由基具有高效的脱硫和降解反应。重复使用实验表明，制备的LCZO光催化剂经过6个反应循环后，对DBT的脱硫和MB的降解均具有良好的稳定性和可回收性。
{"title":"Novel ternary metal oxide nanoparticles (La2Cu0.8Zn0.2O4) as a potential photocatalyst for visible light photocatalytic degradation of methylene blue and desulfurization of dibenzothiophene","authors":"Molood Barmala, M. Behnood","doi":"10.1088/2399-1984/ac3d6e","DOIUrl":"https://doi.org/10.1088/2399-1984/ac3d6e","url":null,"abstract":"In this work we present the preparation of novel ternary metal oxide nanoparticles, La2Cu0.8Zn0.2O4 (LCZO), using a simple co-precipitation method. The crystalline structure, morphology and composition of the prepared LCZO nanoparticles were characterized by x-ray diffraction, scanning electron microscopy and energy-dispersive x-ray analysis. The diffuse reflectance spectrum investigation showed that LCZO nanoparticles have considerable light absorption in the visible light region. Also, the LCZO nanoparticles possess a band-gap energy of 2.82 eV. To investigate the visible light photocatalytic potential of the prepared LCZO nanoparticles, two photocatalytic reactions were conducted, namely degradation of methylene blue (MB) solution and desulfurization of dibenzothiophene (DBT). In the presence of a 3:1 molar ratio of H2O2/DBT, a high photocatalytic desulfurization rate of DBT (93.7%) was obtained over 0.2 g of LCZO photocatalyst. In addition, the photocatalytic degradation rate of MB solution was 91.4%. The mechanisms of both photocatalytic reactions were studied using different radical scavenging agents, which showed that hydroxyl radicals are responsible for highly efficient desulfurization and degradation reactions. Moreover, reusability experiments reveal that the prepared LCZO photocatalyst has great stability and recyclability for both desulfurization of DBT and degradation of MB after six reaction cycles.","PeriodicalId":54222,"journal":{"name":"Nano Futures","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2021-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46645511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-24DOI: 10.1088/2399-1984/ac3ccd
Xin Kuang, Bifeng Yin, Xiping Yang, H. Jia, Bo Xu
The aim of this paper is to evaluate and compare the tribological properties of lubricating oil blends with added nano graphene and nano cerium oxide (CeO2) on the key friction pairs of diesel engines. Dispersion stability is the premise of the study of tribological properties. In this paper, nano CeO2 particles were self-made and high-quality nano graphene was purchased. The dispersion stability of the two nanomaterials in lubricating oil was studied after the same modification. According to the working conditions of the cylinder liner and piston ring, friction and wear tests of the lubricating oil blends containing the modified nanomaterials were carried out at different temperatures. The results showed that both nanomaterials were successfully modified with oleic acid and stearic acid. The dispersion stability of the modified nanomaterials in lubricating oil was improved. The dispersion stability of the lubricating oil blends with graphene before and after modification was slightly higher than that of lubricating oil blends with CeO2 before and after modification. At high temperature, the anti-friction properties of the two nano lubricating oil blends were similar. At ambient temperature, lubricating oil blends containing modified CeO2 did not play a role in reducing friction, while lubricating oil blends with modified graphene had the effect of reducing friction. Whether at ambient temperature or high temperature, the anti-wear property when lubricated with lubricating oil blends with modified CeO2 within the right concentration range was better than that when lubricated with lubricating oil blends containing modified graphene.
{"title":"Study of the tribological properties of nano lubricating oil blends for diesel engines","authors":"Xin Kuang, Bifeng Yin, Xiping Yang, H. Jia, Bo Xu","doi":"10.1088/2399-1984/ac3ccd","DOIUrl":"https://doi.org/10.1088/2399-1984/ac3ccd","url":null,"abstract":"The aim of this paper is to evaluate and compare the tribological properties of lubricating oil blends with added nano graphene and nano cerium oxide (CeO2) on the key friction pairs of diesel engines. Dispersion stability is the premise of the study of tribological properties. In this paper, nano CeO2 particles were self-made and high-quality nano graphene was purchased. The dispersion stability of the two nanomaterials in lubricating oil was studied after the same modification. According to the working conditions of the cylinder liner and piston ring, friction and wear tests of the lubricating oil blends containing the modified nanomaterials were carried out at different temperatures. The results showed that both nanomaterials were successfully modified with oleic acid and stearic acid. The dispersion stability of the modified nanomaterials in lubricating oil was improved. The dispersion stability of the lubricating oil blends with graphene before and after modification was slightly higher than that of lubricating oil blends with CeO2 before and after modification. At high temperature, the anti-friction properties of the two nano lubricating oil blends were similar. At ambient temperature, lubricating oil blends containing modified CeO2 did not play a role in reducing friction, while lubricating oil blends with modified graphene had the effect of reducing friction. Whether at ambient temperature or high temperature, the anti-wear property when lubricated with lubricating oil blends with modified CeO2 within the right concentration range was better than that when lubricated with lubricating oil blends containing modified graphene.","PeriodicalId":54222,"journal":{"name":"Nano Futures","volume":"6 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2021-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43311682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-24DOI: 10.1088/2399-1984/ac3ccc
G. Zeevi, Joanna Dehnel, Adam K. Budniak, Y. Milyutin, G. Ankonina, H. Haick, E. Lifshitz, Y. Yaish
The integration of semiconducting colloidal nanocrystals (NCs) with carbon nanotubes (CNTs) in a single device presents a unique platform that combines optical flexibility with high charge carrying capability. These qualities are desirable in many applications such as photovoltaic cells, photocatalysis, and light sensors. Here, we present hybrid devices that incorporate various CdSe/CdS core/shell NCs, such as seeded quantum dots and asymmetric seeded nanorods (a-sNRs), with a single-wall CNT in a field-effect transistor geometry. We used electrical measurements to probe a light-induced charge transfer (LICT) between the CdSe/CdS NCs and the CNT. We investigate the effect of gate voltage on the LICT magnitude and temporal characteristics. Surprisingly, the measured photo-response depends on the gate voltage, and we observe both electrons and holes transfer from the a-sNRs to the CNT. Furthermore, a comparison between LICT measurements on different devices with different CNTs and NC types reveals that the charge transfer time is directly proportional to the shell-thickness around the CdSe core and inversely correlated with the NCs size. The recovery of the charge trapped inside the CdSe/CdS NCs is characterized by two distinct fast and slow relaxation times, which depend on the NCs size and CNT type. Although, the charge relaxation time is similar between the symmetric QDs and the asymmetric sNRs, the overall percentage of the remaining charge in the QDs is significantly larger than in the sNRs. Understanding both gate voltage and NCs size effect on the LICT processes can optimize the performance of optoelectronic devices.
{"title":"Dynamics of light-induced charge transfer between carbon nanotube and CdSe/CdS core/shell nanocrystals","authors":"G. Zeevi, Joanna Dehnel, Adam K. Budniak, Y. Milyutin, G. Ankonina, H. Haick, E. Lifshitz, Y. Yaish","doi":"10.1088/2399-1984/ac3ccc","DOIUrl":"https://doi.org/10.1088/2399-1984/ac3ccc","url":null,"abstract":"The integration of semiconducting colloidal nanocrystals (NCs) with carbon nanotubes (CNTs) in a single device presents a unique platform that combines optical flexibility with high charge carrying capability. These qualities are desirable in many applications such as photovoltaic cells, photocatalysis, and light sensors. Here, we present hybrid devices that incorporate various CdSe/CdS core/shell NCs, such as seeded quantum dots and asymmetric seeded nanorods (a-sNRs), with a single-wall CNT in a field-effect transistor geometry. We used electrical measurements to probe a light-induced charge transfer (LICT) between the CdSe/CdS NCs and the CNT. We investigate the effect of gate voltage on the LICT magnitude and temporal characteristics. Surprisingly, the measured photo-response depends on the gate voltage, and we observe both electrons and holes transfer from the a-sNRs to the CNT. Furthermore, a comparison between LICT measurements on different devices with different CNTs and NC types reveals that the charge transfer time is directly proportional to the shell-thickness around the CdSe core and inversely correlated with the NCs size. The recovery of the charge trapped inside the CdSe/CdS NCs is characterized by two distinct fast and slow relaxation times, which depend on the NCs size and CNT type. Although, the charge relaxation time is similar between the symmetric QDs and the asymmetric sNRs, the overall percentage of the remaining charge in the QDs is significantly larger than in the sNRs. Understanding both gate voltage and NCs size effect on the LICT processes can optimize the performance of optoelectronic devices.","PeriodicalId":54222,"journal":{"name":"Nano Futures","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2021-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47890798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-23DOI: 10.1088/2399-1984/ac3c8f
Bowen Zheng, Zeyu Zheng, Grace X. Gu
Graphene aerogels (GAs), a special class of 3D graphene assemblies, are well known for their exceptional combination of high strength, lightweightness, and high porosity. However, due to microstructural randomness, the mechanical properties of GAs are also highly stochastic, an issue that has been observed but insufficiently addressed. In this work, we develop Gaussian process metamodels to not only predict important mechanical properties of GAs but also quantify their uncertainties. Using the molecular dynamics simulation technique, GAs are assembled from randomly distributed graphene flakes and spherical inclusions, and are subsequently subject to a quasi-static uniaxial tensile load to deduce mechanical properties. Results show that given the same density, mechanical properties such as the Young’s modulus and the ultimate tensile strength can vary substantially. Treating density, Young’s modulus, and ultimate tensile strength as functions of the inclusion size, and using the simulated GA results as training data, we build Gaussian process metamodels that can efficiently predict the properties of unseen GAs. In addition, statistically valid confidence intervals centered around the predictions are established. This metamodel approach is particularly beneficial when the data acquisition requires expensive experiments or computation, which is the case for GA simulations. The present research quantifies the uncertain mechanical properties of GAs, which may shed light on the statistical analysis of novel nanomaterials of a broad variety.
{"title":"Uncertainty quantification and prediction for mechanical properties of graphene aerogels via Gaussian process metamodels","authors":"Bowen Zheng, Zeyu Zheng, Grace X. Gu","doi":"10.1088/2399-1984/ac3c8f","DOIUrl":"https://doi.org/10.1088/2399-1984/ac3c8f","url":null,"abstract":"Graphene aerogels (GAs), a special class of 3D graphene assemblies, are well known for their exceptional combination of high strength, lightweightness, and high porosity. However, due to microstructural randomness, the mechanical properties of GAs are also highly stochastic, an issue that has been observed but insufficiently addressed. In this work, we develop Gaussian process metamodels to not only predict important mechanical properties of GAs but also quantify their uncertainties. Using the molecular dynamics simulation technique, GAs are assembled from randomly distributed graphene flakes and spherical inclusions, and are subsequently subject to a quasi-static uniaxial tensile load to deduce mechanical properties. Results show that given the same density, mechanical properties such as the Young’s modulus and the ultimate tensile strength can vary substantially. Treating density, Young’s modulus, and ultimate tensile strength as functions of the inclusion size, and using the simulated GA results as training data, we build Gaussian process metamodels that can efficiently predict the properties of unseen GAs. In addition, statistically valid confidence intervals centered around the predictions are established. This metamodel approach is particularly beneficial when the data acquisition requires expensive experiments or computation, which is the case for GA simulations. The present research quantifies the uncertain mechanical properties of GAs, which may shed light on the statistical analysis of novel nanomaterials of a broad variety.","PeriodicalId":54222,"journal":{"name":"Nano Futures","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2021-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46786747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-22DOI: 10.1088/2399-1984/ac3bd4
Min-Won Kim, Ji-Hun Kim, Jun-Seong Park, Byoung-Seok Lee, S. Yoo, T. Shim, Jea‐Gun Park
In a two-terminal-electrode vertical thyristor, the latch-up and latch-down voltages are decreased when the memory operation temperature of the memory cells increases, resulting in a severe reliability issue (i.e. thermal instability). This study fundamentally solves the thermal instability of a vertical-thyristor by achieving a cross-point memory-cell array using a vertical-thyristor with a structure of vertical n++-emitter, p+-base, n+-base, and p++-emitter. The vertical-thyristor using a Schottky contact metal emitter instead of an n++-Si emitter significantly improves the thermal stability between 293 K and 373 K. Particularly, the improvement degree of the thermal stability is increased significantly with the use of the Schottky contact metal work function. Because the thermal instability (i.e. degree of latch-up voltage decrement vs. memory operation temperature) decreases with an increase in the Schottky contact metal work function, the dependency of the forward current density between the Schottky contact metal and p+-Si based on the memory operation temperature reduces with increase in the Schottky contact metal work function. Consequently, a higher Schottky contact metal work function produces a higher degree of improvement in the thermal stability, i.e. W (4.50 eV), Ti (4.33 eV), Ta (4.25 eV), and Al (4.12 eV). Further research on the fabrication process of a Schottky contact metal emitter vertical-thyristor is essential for the fabrication of a 3D cross-point memory-cell.
{"title":"Two-terminal vertical thyristor using Schottky contact emitter to improve thermal instability","authors":"Min-Won Kim, Ji-Hun Kim, Jun-Seong Park, Byoung-Seok Lee, S. Yoo, T. Shim, Jea‐Gun Park","doi":"10.1088/2399-1984/ac3bd4","DOIUrl":"https://doi.org/10.1088/2399-1984/ac3bd4","url":null,"abstract":"In a two-terminal-electrode vertical thyristor, the latch-up and latch-down voltages are decreased when the memory operation temperature of the memory cells increases, resulting in a severe reliability issue (i.e. thermal instability). This study fundamentally solves the thermal instability of a vertical-thyristor by achieving a cross-point memory-cell array using a vertical-thyristor with a structure of vertical n++-emitter, p+-base, n+-base, and p++-emitter. The vertical-thyristor using a Schottky contact metal emitter instead of an n++-Si emitter significantly improves the thermal stability between 293 K and 373 K. Particularly, the improvement degree of the thermal stability is increased significantly with the use of the Schottky contact metal work function. Because the thermal instability (i.e. degree of latch-up voltage decrement vs. memory operation temperature) decreases with an increase in the Schottky contact metal work function, the dependency of the forward current density between the Schottky contact metal and p+-Si based on the memory operation temperature reduces with increase in the Schottky contact metal work function. Consequently, a higher Schottky contact metal work function produces a higher degree of improvement in the thermal stability, i.e. W (4.50 eV), Ti (4.33 eV), Ta (4.25 eV), and Al (4.12 eV). Further research on the fabrication process of a Schottky contact metal emitter vertical-thyristor is essential for the fabrication of a 3D cross-point memory-cell.","PeriodicalId":54222,"journal":{"name":"Nano Futures","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2021-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42429776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-04DOI: 10.1088/2399-1984/ac36b5
Fayong Liu, M. Muruganathan, Yu-Lun Feng, Shinichi Ogawa, Y. Morita, Chunmeng Liu, Jiayu Guo, Marek E. Schmidt, H. Mizuta
Graphene-based thermal rectification was investigated by measuring the thermal transport properties of asymmetric suspended graphene nanomesh devices. A sub-10 nm periodic nanopore phononic crystal structure was successfully patterned on the half area of the suspended graphene ribbon by helium ion beam milling technology. The ‘differential thermal leakage’ method was developed for thermal transport measurement without disturbance from the leakage of electron current through the suspended graphene bridge. A thermal rectification ratio of up to 60% was observed in a typical device with a nanopore pitch of 20 nm. By increasing the nanopore pitch in a particular range, the thermal rectification ratio showed an increment. However, this ratio was degraded by increasing the environmental temperature. This experiment suggests a promising way to develop a high-performance thermal rectifier by using a phononic crystal to introduce asymmetry on homogeneous material.
{"title":"Thermal rectification on asymmetric suspended graphene nanomesh devices","authors":"Fayong Liu, M. Muruganathan, Yu-Lun Feng, Shinichi Ogawa, Y. Morita, Chunmeng Liu, Jiayu Guo, Marek E. Schmidt, H. Mizuta","doi":"10.1088/2399-1984/ac36b5","DOIUrl":"https://doi.org/10.1088/2399-1984/ac36b5","url":null,"abstract":"Graphene-based thermal rectification was investigated by measuring the thermal transport properties of asymmetric suspended graphene nanomesh devices. A sub-10 nm periodic nanopore phononic crystal structure was successfully patterned on the half area of the suspended graphene ribbon by helium ion beam milling technology. The ‘differential thermal leakage’ method was developed for thermal transport measurement without disturbance from the leakage of electron current through the suspended graphene bridge. A thermal rectification ratio of up to 60% was observed in a typical device with a nanopore pitch of 20 nm. By increasing the nanopore pitch in a particular range, the thermal rectification ratio showed an increment. However, this ratio was degraded by increasing the environmental temperature. This experiment suggests a promising way to develop a high-performance thermal rectifier by using a phononic crystal to introduce asymmetry on homogeneous material.","PeriodicalId":54222,"journal":{"name":"Nano Futures","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2021-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44020411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-09DOI: 10.1088/2399-1984/ac1bfc
Deepika Chauhan, Smriti Sri, Robin Kumar, A. Panda, P. Solanki
Gadolinium (Gd) has a strong paramagnetic response and is used in advanced magnetic resonance imaging (MRI). Gd is used in the complex form in MRI, but these complexes lack in sensitivity, targeting, rapid elimination from the body, and low internalization into the cell. To replace these Gd complex, the nanostructure (NSs) form of Gd has emerged as a viable solution as the NSs are expected to increase cell uptake and biocompatibility. The cytotoxicity evaluation is the key component that needs to be addressed for translating NSs from the lab to the clinic, and their effect on the cells is a vast area of research. Hence, the present study reports the hydrothermal synthesis of gadolinium oxide nanorods (Gd2O3 NRs) and ex-situ functionalized with aspartic acid (Asp-Gd2O3 NRs). The cytotoxicity studies on two cells namely RAW 264.7 and MCF-7 was assessed in terms of cell viability, morphological changes, and cell cycle analysis. Both types of NRs were well characterized and it was found that Asp-Gd2O3 NRs exhibited enhanced hydrophilicity and dispersity. Cell viability assay revealed enhanced biocompatibility of Asp-Gd2O3 NRs with almost 75% viability even at a higher concentration of 250 µg ml−1. The morphological changes upon internalization of both NRs were done through fluorescent microscopy that revealed no significant change in the morphology of the cell or its nucleus. Further, the cell cycle studies again confirmed the biocompatible nature of these NRs. These results suggest that Asp-Gd2O3 NRs are well suited for therapeutic applications, such as thermal cancer therapy, due to their tunable shape, size, low toxicity, and the possibility of surface modification.
{"title":"Assessment of cytotoxicity profile of gadolinium oxide nanorods and the analogous surface-functionalized nanorods","authors":"Deepika Chauhan, Smriti Sri, Robin Kumar, A. Panda, P. Solanki","doi":"10.1088/2399-1984/ac1bfc","DOIUrl":"https://doi.org/10.1088/2399-1984/ac1bfc","url":null,"abstract":"Gadolinium (Gd) has a strong paramagnetic response and is used in advanced magnetic resonance imaging (MRI). Gd is used in the complex form in MRI, but these complexes lack in sensitivity, targeting, rapid elimination from the body, and low internalization into the cell. To replace these Gd complex, the nanostructure (NSs) form of Gd has emerged as a viable solution as the NSs are expected to increase cell uptake and biocompatibility. The cytotoxicity evaluation is the key component that needs to be addressed for translating NSs from the lab to the clinic, and their effect on the cells is a vast area of research. Hence, the present study reports the hydrothermal synthesis of gadolinium oxide nanorods (Gd2O3 NRs) and ex-situ functionalized with aspartic acid (Asp-Gd2O3 NRs). The cytotoxicity studies on two cells namely RAW 264.7 and MCF-7 was assessed in terms of cell viability, morphological changes, and cell cycle analysis. Both types of NRs were well characterized and it was found that Asp-Gd2O3 NRs exhibited enhanced hydrophilicity and dispersity. Cell viability assay revealed enhanced biocompatibility of Asp-Gd2O3 NRs with almost 75% viability even at a higher concentration of 250 µg ml−1. The morphological changes upon internalization of both NRs were done through fluorescent microscopy that revealed no significant change in the morphology of the cell or its nucleus. Further, the cell cycle studies again confirmed the biocompatible nature of these NRs. These results suggest that Asp-Gd2O3 NRs are well suited for therapeutic applications, such as thermal cancer therapy, due to their tunable shape, size, low toxicity, and the possibility of surface modification.","PeriodicalId":54222,"journal":{"name":"Nano Futures","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49056658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-23DOI: 10.1088/2399-1984/ac0c24
Z. Dang, Yuqing Luo, Yangbing Xu, Pingqi Gao, Xueseng Wang
Transmission electron microscopy (TEM) has been used in the characterizations of the lattice and defect structures as well as electronic and chemical properties of various materials. When TEM analyses were performed on lead halide perovskites (LHPs) and related materials, it has often been found that transformation and damage were easily induced in the specimens by electron beam irradiation. As the structural and chemical instabilities of LHPs and related materials are the main obstacle that must be overcome for their practical large-scale applications in solar cells and other optoelectronic applications, we examine whether and how the TEM-based irradiation and analyses can serve the purpose of rapid evaluation of the instabilities of a LHP to stimuli such as light and electric field which are crucial to its optoelectronic applications. We first provide a brief overview of the basic physical properties of LHPs related to the instability and the current understanding of the general mechanisms of sample damages induced by energetic electrons, followed with an analysis of the distinctive vulnerability and damaging features of LHPs with respect to electron beam irradiation. Based on the analysis of the similarities in the mechanisms of the damages generated by different stimuli, proper conditions are outlined with which the TEM-based investigations can be employed as a speed-up tester for the instabilities of LHPs against photon (including visible, ultraviolet and x-ray) exposure and an applied electric field. Furthermore, the perspectives of employing TEM-based processes in the fabrication of nanostructures and directly carrying out subsequent in situ analysis are elaborated, which is key to acquiring knowledge for improving focused electron beam-based industrial micro- and nanofabrication technologies.
{"title":"Transformation and degradation of metal halide perovskites induced by energetic electrons and their practical implications","authors":"Z. Dang, Yuqing Luo, Yangbing Xu, Pingqi Gao, Xueseng Wang","doi":"10.1088/2399-1984/ac0c24","DOIUrl":"https://doi.org/10.1088/2399-1984/ac0c24","url":null,"abstract":"Transmission electron microscopy (TEM) has been used in the characterizations of the lattice and defect structures as well as electronic and chemical properties of various materials. When TEM analyses were performed on lead halide perovskites (LHPs) and related materials, it has often been found that transformation and damage were easily induced in the specimens by electron beam irradiation. As the structural and chemical instabilities of LHPs and related materials are the main obstacle that must be overcome for their practical large-scale applications in solar cells and other optoelectronic applications, we examine whether and how the TEM-based irradiation and analyses can serve the purpose of rapid evaluation of the instabilities of a LHP to stimuli such as light and electric field which are crucial to its optoelectronic applications. We first provide a brief overview of the basic physical properties of LHPs related to the instability and the current understanding of the general mechanisms of sample damages induced by energetic electrons, followed with an analysis of the distinctive vulnerability and damaging features of LHPs with respect to electron beam irradiation. Based on the analysis of the similarities in the mechanisms of the damages generated by different stimuli, proper conditions are outlined with which the TEM-based investigations can be employed as a speed-up tester for the instabilities of LHPs against photon (including visible, ultraviolet and x-ray) exposure and an applied electric field. Furthermore, the perspectives of employing TEM-based processes in the fabrication of nanostructures and directly carrying out subsequent in situ analysis are elaborated, which is key to acquiring knowledge for improving focused electron beam-based industrial micro- and nanofabrication technologies.","PeriodicalId":54222,"journal":{"name":"Nano Futures","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2021-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42510393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-04DOI: 10.1088/2399-1984/ac14c8
Z. Balogh, G. Mezei, László Pósa, Botond Sánta, A. Magyarkuti, A. Halbritter
In this paper, we review the 1/f-type noise properties of nanoelectronic devices focusing on three demonstrative platforms: resistive switching memories, graphene nanogaps and single-molecule nanowires. The functionality of such ultrasmall devices is confined to an extremely small volume, where bulk considerations on the noise lose their validity: the relative contribution of a fluctuator heavily depends on its distance from the device bottleneck, and the noise characteristics are sensitive to the nanometer-scale device geometry and details of the mostly non-classical transport mechanism. All these are reflected by a highly system-specific dependence of the noise properties on the active device volume (and the related device resistance), the frequency, or the applied voltage. Accordingly, 1/f-type noise measurements serve as a rich fingerprint of the relevant transport and noise-generating mechanisms in the studied nanoelectronic systems. Finally, we demonstrate that not only the fundamental understanding and the targeted noise suppression is fueled by the 1/f-type noise analysis, but novel probabilistic computing hardware platforms heavily seek well tailorable nanoelectric noise sources.
{"title":"1/f noise spectroscopy and noise tailoring of nanoelectronic devices","authors":"Z. Balogh, G. Mezei, László Pósa, Botond Sánta, A. Magyarkuti, A. Halbritter","doi":"10.1088/2399-1984/ac14c8","DOIUrl":"https://doi.org/10.1088/2399-1984/ac14c8","url":null,"abstract":"In this paper, we review the 1/f-type noise properties of nanoelectronic devices focusing on three demonstrative platforms: resistive switching memories, graphene nanogaps and single-molecule nanowires. The functionality of such ultrasmall devices is confined to an extremely small volume, where bulk considerations on the noise lose their validity: the relative contribution of a fluctuator heavily depends on its distance from the device bottleneck, and the noise characteristics are sensitive to the nanometer-scale device geometry and details of the mostly non-classical transport mechanism. All these are reflected by a highly system-specific dependence of the noise properties on the active device volume (and the related device resistance), the frequency, or the applied voltage. Accordingly, 1/f-type noise measurements serve as a rich fingerprint of the relevant transport and noise-generating mechanisms in the studied nanoelectronic systems. Finally, we demonstrate that not only the fundamental understanding and the targeted noise suppression is fueled by the 1/f-type noise analysis, but novel probabilistic computing hardware platforms heavily seek well tailorable nanoelectric noise sources.","PeriodicalId":54222,"journal":{"name":"Nano Futures","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2021-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46484793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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