Pub Date : 2023-11-10DOI: 10.1007/s13391-023-00467-8
Tran Thi Ngoc Van, Bonggeun Shong
Atomic layer deposition (ALD) is a promising technique for fabricating high-quality thin films. For improving the process conditions and material quality of ALD, understanding the surface chemical mechanisms at the molecular level is important as the entire ALD process is based on the reactions of precursors on the substrate surfaces. Zinc oxynitride (ZnON) is gaining significant research interest as a p-type semiconductor material. Although the ALD of ZnON can be performed by dosing H2O and NH3 as oxygen and nitrogen sources, respectively, the elemental ratio of O and N in the deposited film differs considerably from that in the gaseous sources. In this study, the surface reactions of ZnON ALD are analyzed employing density functional theory calculations. All the ALD surface reactions of ZnO and ZnN are facile and expected to occur rapidly. However, the substitution of a surface *NH2 by H2O to form *OH is preferred, whereas the inverse reaction is implausible. We propose that the differences in the reactivity could originate from the higher bond energy of Zn–O than that of Zn–N.
{"title":"Surface Chemical Reactions During Atomic Layer Deposition of Zinc Oxynitride (ZnON)","authors":"Tran Thi Ngoc Van, Bonggeun Shong","doi":"10.1007/s13391-023-00467-8","DOIUrl":"10.1007/s13391-023-00467-8","url":null,"abstract":"<div><p>Atomic layer deposition (ALD) is a promising technique for fabricating high-quality thin films. For improving the process conditions and material quality of ALD, understanding the surface chemical mechanisms at the molecular level is important as the entire ALD process is based on the reactions of precursors on the substrate surfaces. Zinc oxynitride (ZnON) is gaining significant research interest as a<i> p</i>-type semiconductor material. Although the ALD of ZnON can be performed by dosing H<sub>2</sub>O and NH<sub>3</sub> as oxygen and nitrogen sources, respectively, the elemental ratio of O and N in the deposited film differs considerably from that in the gaseous sources. In this study, the surface reactions of ZnON ALD are analyzed employing density functional theory calculations. All the ALD surface reactions of ZnO and ZnN are facile and expected to occur rapidly. However, the substitution of a surface *NH<sub>2</sub> by H<sub>2</sub>O to form *OH is preferred, whereas the inverse reaction is implausible. We propose that the differences in the reactivity could originate from the higher bond energy of Zn–O than that of Zn–N.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"20 4","pages":"500 - 507"},"PeriodicalIF":2.1,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135141879","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 : 2023-11-08DOI: 10.1007/s13391-023-00466-9
Yunnan Fang, Manos M. Tentzeris
This work reports the first demonstration that a chemoresistive sensor can be used to detect the aggregation pheromone of flour beetles. To prepare the sensing element of such a sensor, a novel functionalization method was developed to amplify amine groups on the surface of carbon nanotubes (CNTs). Unlike traditional amine-amplification approaches in which amplification efficiency is significantly reduced by self-crosslinking, the current amine amplification process was self-crosslinking-free due to the use of a home-made compound in which amine groups were protected by Boc (tert-butyloxycarbonyl) protecting groups and could be deprotected as needed. The inkjet ink formulated from the functionalized CNTs, together with an amine-rich compound and a commercial silver nanoparticle-based inkjet ink, was used to fabricate (via inkjet-printing and drop-casting) lightweight, flexible, and miniature-sized chemiresistive sensors for 4,8-dimethyldecanal (DMD), a compound known to be the aggregation pheromone of several species of flour beetles. A home-built gas sensing system, including a commercial gas generator, a DMD permeation tube with its emission rate certified, a data-acquisition system, and some home-developed LabVIEW-based programs, was utilized to perform the DMD sensing trials. The sensors showed ultra-high sensitivity to synthetic aggregation pheromone DMD, as indicated by their prompt and significant responses to 100 ppb DMD vapor. A mechanism for the sensitive sensing of DMD is proposed.
{"title":"Inkjet-Printed Flexible Ultrasensitive Chemiresistive Sensors for Aggregation Pheromone of Flour Beetles","authors":"Yunnan Fang, Manos M. Tentzeris","doi":"10.1007/s13391-023-00466-9","DOIUrl":"10.1007/s13391-023-00466-9","url":null,"abstract":"<div><p>This work reports the first demonstration that a chemoresistive sensor can be used to detect the aggregation pheromone of flour beetles. To prepare the sensing element of such a sensor, a novel functionalization method was developed to amplify amine groups on the surface of carbon nanotubes (CNTs). Unlike traditional amine-amplification approaches in which amplification efficiency is significantly reduced by self-crosslinking, the current amine amplification process was self-crosslinking-free due to the use of a home-made compound in which amine groups were protected by Boc (tert-butyloxycarbonyl) protecting groups and could be deprotected as needed. The inkjet ink formulated from the functionalized CNTs, together with an amine-rich compound and a commercial silver nanoparticle-based inkjet ink, was used to fabricate (via inkjet-printing and drop-casting) lightweight, flexible, and miniature-sized chemiresistive sensors for 4,8-dimethyldecanal (DMD), a compound known to be the aggregation pheromone of several species of flour beetles. A home-built gas sensing system, including a commercial gas generator, a DMD permeation tube with its emission rate certified, a data-acquisition system, and some home-developed LabVIEW-based programs, was utilized to perform the DMD sensing trials. The sensors showed ultra-high sensitivity to synthetic aggregation pheromone DMD, as indicated by their prompt and significant responses to 100 ppb DMD vapor. A mechanism for the sensitive sensing of DMD is proposed.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"20 3","pages":"244 - 253"},"PeriodicalIF":2.1,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135341583","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 : 2023-11-07DOI: 10.1007/s13391-023-00465-w
Chen Li, Yangtong Luo, Zhangyan Wang, Chengyong Zhong, Shuo Li
The utilization of two-dimensional porous materials as anodes in ion batteries has garnered significant interest within the field of clean energy because of their flexible architecture, high conductivity, rapid diffusion process and high specific ion capacity. Herein, we developed a new metal-free 2D porous compound, namely, B4O2. The stability of the B4O2 monolayer was verified through the ab-initio molecular dynamics simulations and phonon spectrum calculations. The results demonstrate that the adsorption of K, Na, and Li atoms onto the B4O2 monolayer surface is remarkably stable, with all three species exhibiting a shared diffusion path. Specifically, we found that the adsorption of K atoms on the B4O2 monolayer surpasses that of Na and Li atoms, and the diffusion of K atoms occurs at a faster rate than Na and Li atoms on the same monolayer surface. The maximum theoretical specific capacity of K+, Na+ and Li+ is calculated to be 626.1 mAh/g. In addition, the B4O2 monolayer retains good electronic conductivity and electron activity during the atomic adsorption processes. Based on our findings, the B4O2 monolayer exhibits significant potential as anode material for ion batteries. This study paves the way for a novel approach in designing new 2D porous materials specifically tailored for energy storage and conversion applications.
Graphical Abstract
由于二维多孔材料具有灵活的结构、高导电性、快速扩散过程和高比离子容量，因此将其用作离子电池的阳极在清洁能源领域引起了极大的兴趣。在此，我们开发了一种新型无金属二维多孔化合物，即 B4O2。通过非线性分子动力学模拟和声子谱计算验证了 B4O2 单层的稳定性。结果表明，K、Na 和 Li 原子在 B4O2 单层表面的吸附非常稳定，而且这三种原子都有共同的扩散路径。具体来说，我们发现 K 原子在 B4O2 单层上的吸附量超过了 Na 原子和 Li 原子，而且 K 原子在同一单层表面上的扩散速度快于 Na 原子和 Li 原子。经计算，K+、Na+ 和 Li+ 的最大理论比容量为 626.1 mAh/g。此外，B4O2 单层在原子吸附过程中保持了良好的电子导电性和电子活性。根据我们的研究结果，B4O2 单层作为离子电池的阳极材料具有巨大的潜力。这项研究为设计专门用于能量储存和转换应用的新型二维多孔材料铺平了道路。
{"title":"An Ideal Two-Dimensional Porous B4O2 as Anode Material for Enhancing Ion Storage Performance","authors":"Chen Li, Yangtong Luo, Zhangyan Wang, Chengyong Zhong, Shuo Li","doi":"10.1007/s13391-023-00465-w","DOIUrl":"10.1007/s13391-023-00465-w","url":null,"abstract":"<div><p>The utilization of two-dimensional porous materials as anodes in ion batteries has garnered significant interest within the field of clean energy because of their flexible architecture, high conductivity, rapid diffusion process and high specific ion capacity. Herein, we developed a new metal-free 2D porous compound, namely, B<sub>4</sub>O<sub>2</sub>. The stability of the B<sub>4</sub>O<sub>2</sub> monolayer was verified through the ab-initio molecular dynamics simulations and phonon spectrum calculations. The results demonstrate that the adsorption of K, Na, and Li atoms onto the B<sub>4</sub>O<sub>2</sub> monolayer surface is remarkably stable, with all three species exhibiting a shared diffusion path. Specifically, we found that the adsorption of K atoms on the B<sub>4</sub>O<sub>2</sub> monolayer surpasses that of Na and Li atoms, and the diffusion of K atoms occurs at a faster rate than Na and Li atoms on the same monolayer surface. The maximum theoretical specific capacity of K<sup>+</sup>, Na<sup>+</sup> and Li<sup>+</sup> is calculated to be 626.1 mAh/g. In addition, the B<sub>4</sub>O<sub>2</sub> monolayer retains good electronic conductivity and electron activity during the atomic adsorption processes. Based on our findings, the B<sub>4</sub>O<sub>2</sub> monolayer exhibits significant potential as anode material for ion batteries. This study paves the way for a novel approach in designing new 2D porous materials specifically tailored for energy storage and conversion applications.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"20 3","pages":"275 - 282"},"PeriodicalIF":2.1,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135432681","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 : 2023-11-02DOI: 10.1007/s13391-023-00469-6
Fang Wang, Yu Liu, Tian Yu, Cai, Wenfeng Xiang
In recent years, significant attention has been directed toward exploring heterojunctions based on perovskite materials for ultraviolet photodetectors. This study focuses on the fabrication of high-quality single-crystal Nb:SrTiO3 (NSTO) films on Si substrates, achieved through the utilization of a TiN thin film as a buffer layer. The investigation delves into the lateral photovoltaic effect exhibited by the film. Characterization using X-ray diffraction and high-resolution transmission electron microscopy confirms the exceptional quality of the NSTO film. Notably, the observed position sensitivity attains an impressive value of 43.9 mV mm−1. Analysis of the lateral photovoltaic effect reveals response and relaxation times of approximately 105.6 ns and 4.49 µs, respectively. Intriguingly, fitting results for the relaxation time indicate minimal defects within the NSTO/TiN/Si heterostructures. These findings underscore the significant potential of NSTO/TiN/Si heterojunctions, presenting a promising avenue for their widespread application in the realm of position change technology.
Graphical Abstract
近年来，基于包晶体材料的紫外光探测器异质结的研究备受关注。本研究的重点是通过使用 TiN 薄膜作为缓冲层，在硅基底上制备高质量的单晶 Nb:SrTiO3 (NSTO) 薄膜。该研究深入探讨了薄膜表现出的横向光伏效应。利用 X 射线衍射和高分辨率透射电子显微镜进行的表征证实了 NSTO 薄膜的卓越品质。值得注意的是，观察到的位置灵敏度达到了令人印象深刻的 43.9 mV mm-1。对横向光伏效应的分析表明，响应时间和弛豫时间分别约为 105.6 毫微秒和 4.49 微秒。有趣的是，弛豫时间的拟合结果表明，NSTO/TiN/Si 异质结构中的缺陷极少。这些发现凸显了 NSTO/TiN/Si 异质结的巨大潜力，为其在位置变化技术领域的广泛应用提供了前景广阔的途径。
{"title":"Near-Ultraviolet Lateral Photovoltaic Effect of Epitaxial Nb:SrTiO3 Films on Si Substrate Using TiN as a Buffer Layer","authors":"Fang Wang, Yu Liu, Tian Yu, Cai, Wenfeng Xiang","doi":"10.1007/s13391-023-00469-6","DOIUrl":"10.1007/s13391-023-00469-6","url":null,"abstract":"<div><p>In recent years, significant attention has been directed toward exploring heterojunctions based on perovskite materials for ultraviolet photodetectors. This study focuses on the fabrication of high-quality single-crystal Nb:SrTiO<sub>3</sub> (NSTO) films on Si substrates, achieved through the utilization of a TiN thin film as a buffer layer. The investigation delves into the lateral photovoltaic effect exhibited by the film. Characterization using X-ray diffraction and high-resolution transmission electron microscopy confirms the exceptional quality of the NSTO film. Notably, the observed position sensitivity attains an impressive value of 43.9 mV mm−1. Analysis of the lateral photovoltaic effect reveals response and relaxation times of approximately 105.6 ns and 4.49 µs, respectively. Intriguingly, fitting results for the relaxation time indicate minimal defects within the NSTO/TiN/Si heterostructures. These findings underscore the significant potential of NSTO/TiN/Si heterojunctions, presenting a promising avenue for their widespread application in the realm of position change technology.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"20 3","pages":"269 - 274"},"PeriodicalIF":2.1,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135934212","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 : 2023-10-30DOI: 10.1007/s13391-023-00468-7
Seung Jo Yoo, Tae Gyu Yun, Jae Hyuck Jang, Ji-Hyun Lee, Changhyun Park, Sung-Yoon Chung
The formation of oxygen vacancies in heteroepitaxial LaCoO3 thin films deposited on different substrates was investigated by using electron beam irradiation in atomic-scale scanning transmission electron microscopy (STEM). As the electron beam irradiation intensified, distinctive dark stripe patterns were identified in high-angle annular dark-field STEM images, demonstrating the formation and subsequent ordering of oxygen vacancies. A comprehensive quantitative analysis of the lattice parameter changes verified the significant expansion of unit cells associated with the presence of oxygen vacancies. In particular, a uniform distribution of these expanded unit cells was observed in the films under large tensile strain. These experimental findings emphasize the significant role of strain in generating oxygen vacancies in perovskite oxide materials.
{"title":"Electron-Beam-Induced Formation of Oxygen Vacancies in Epitaxial LaCoO3 Thin Films","authors":"Seung Jo Yoo, Tae Gyu Yun, Jae Hyuck Jang, Ji-Hyun Lee, Changhyun Park, Sung-Yoon Chung","doi":"10.1007/s13391-023-00468-7","DOIUrl":"10.1007/s13391-023-00468-7","url":null,"abstract":"<div><p>The formation of oxygen vacancies in heteroepitaxial LaCoO<sub>3</sub> thin films deposited on different substrates was investigated by using electron beam irradiation in atomic-scale scanning transmission electron microscopy (STEM). As the electron beam irradiation intensified, distinctive dark stripe patterns were identified in high-angle annular dark-field STEM images, demonstrating the formation and subsequent ordering of oxygen vacancies. A comprehensive quantitative analysis of the lattice parameter changes verified the significant expansion of unit cells associated with the presence of oxygen vacancies. In particular, a uniform distribution of these expanded unit cells was observed in the films under large tensile strain. These experimental findings emphasize the significant role of strain in generating oxygen vacancies in perovskite oxide materials.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"20 4","pages":"491 - 499"},"PeriodicalIF":2.1,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136103635","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 : 2023-10-24DOI: 10.1007/s13391-023-00464-x
Aryal Krishna Prasad, Jong-Young Park, Soon-Hyung Kang, Kwang-Soon Ahn
Reduced graphene oxide (rGO)-embedded WO3 composite thin film (rGO-WO3) is synthesized and investigated for its electrochromic performances. Furthermore, a novel application of quantum dot-sensitized solar cells (QDSSCs), to operate the rGO-WO3 electrochromic devices (ECDs), is demonstrated with development of an integrated device. The co-existence of both WO3 nanostructure and rGO sheet ameliorates the EC performances of composite thin film, compared to WO3 thin film. The rGO-WO3, possessing 0.1 g of rGO, nanocomposite shows an optimum optical contrast (%ΔT) of 66.3% and excellent optical stability displaying 1.7% degradation in %ΔT, while the WO3 film only exhibits a %ΔT of 52.2% and, 4.2% of optical degradation. Incorporation of rGO sheet into the WO3 nanostructure introduces de-agglomerated morphology, enhances electrochemically active surface area, and which facilitates the ion-transfer kinetics. The series-connected QDSSCs results an optimum open circuit voltage (Voc) of 1.03 V upon 1 sun illumination, which is found to be adequate for the study of switching performances of ECDs. QDSSCs assisted rGO-WO3 EC film exhibits a significant %ΔT of 43% and coloration time of 7 s. Additionally, QDSSCs device is illuminated with various light intensities to study the intensity and Voc dependent EC performances of rGO-WO3.
{"title":"Electrochromic Performances of rGO-WO3 Thin Film and Its Application as an Integrated Device Powered with Quantum Dot-Sensitized Solar Cells","authors":"Aryal Krishna Prasad, Jong-Young Park, Soon-Hyung Kang, Kwang-Soon Ahn","doi":"10.1007/s13391-023-00464-x","DOIUrl":"10.1007/s13391-023-00464-x","url":null,"abstract":"<div><p>Reduced graphene oxide (rGO)-embedded WO<sub>3</sub> composite thin film (rGO-WO<sub>3</sub>) is synthesized and investigated for its electrochromic performances. Furthermore, a novel application of quantum dot-sensitized solar cells (QDSSCs), to operate the rGO-WO<sub>3</sub> electrochromic devices (ECDs), is demonstrated with development of an integrated device. The co-existence of both WO<sub>3</sub> nanostructure and rGO sheet ameliorates the EC performances of composite thin film, compared to WO<sub>3</sub> thin film. The rGO-WO<sub>3</sub>, possessing 0.1 g of rGO, nanocomposite shows an optimum optical contrast (%ΔT) of 66.3% and excellent optical stability displaying 1.7% degradation in %ΔT, while the WO<sub>3</sub> film only exhibits a %ΔT of 52.2% and, 4.2% of optical degradation. Incorporation of rGO sheet into the WO<sub>3</sub> nanostructure introduces de-agglomerated morphology, enhances electrochemically active surface area, and which facilitates the ion-transfer kinetics. The series-connected QDSSCs results an optimum open circuit voltage (V<sub>oc</sub>) of 1.03 V upon 1 sun illumination, which is found to be adequate for the study of switching performances of ECDs. QDSSCs assisted rGO-WO<sub>3</sub> EC film exhibits a significant %ΔT of 43% and coloration time of 7 s. Additionally, QDSSCs device is illuminated with various light intensities to study the intensity and V<sub>oc</sub> dependent EC performances of rGO-WO<sub>3</sub>.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"20 6","pages":"756 - 766"},"PeriodicalIF":2.1,"publicationDate":"2023-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135266441","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 : 2023-10-24DOI: 10.1007/s13391-023-00461-0
Hyo-Min Choi, Jong-Won Yoon
Co3O4 with a spinel structure has been utilized as supercapacitor materials due to their active surface sites, strong absorption capacity, excellent electrochemical activity, and stability. In this study, we tried to explore the optimized electrospinning conditions, including heat-treatment temperature for Co3O4 nanofiber fabrication for supercapacitor applications. The X-ray diffraction patterns of Co3O4 nanofibers annealed at 600 and 800 ºC showed a cubic spinel crystal structure without a secondary phase, but CoO was found in the specimens annealed at 400 ºC. From the XPS curve fitting, Co3+ increased in the Co3+/Co2+ ratio with increasing heat-treatment temperature. The electrical conductivity of the Co3O4 nanofibers heated at 400, 600, and 800 ºC is 7.53 × 10−3, 1.12 × 10−2, and 6.26 × 10−3 Ω−1 cm−1, respectively. The Co3O4 nanofibers heat treated at 600 ºC showed the highest conductivity value, and the conduction mechanism was polaron hopping between Co3+ and Co2+. The supercapacitor properties of Co3O4 nanofibers are evaluated by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance measurement using a three-electrode system in a 3 M KOH electrolyte. The GCD tests showed that the Co3O4 nanofibers heated at 600 ºC had the highest specific capacitance of 579.66 F/g. From the electrochemical impedance measurements, the charge transfer resistance (Rct) of calcined Co3O4 nanofibers at 600 ºC showed the lowest value of 1.27 Ω. Also, the Co3O4 nanofiber exhibits excellent cycle stability with capacitance retention over 99% until 1000 cycles at a current density of 2 A/g. Therefore, the excellent supercapacitor performance of Co3O4 nanofibers annealed at 600 ºC is due to its nanofiber structure without a secondary phase providing a larger surface area and charge transfer.
{"title":"Relationship Between Electrical Conductivity and Supercapacitor Properties of Co3O4 Nanofibers Fabricated by Electrospinning","authors":"Hyo-Min Choi, Jong-Won Yoon","doi":"10.1007/s13391-023-00461-0","DOIUrl":"10.1007/s13391-023-00461-0","url":null,"abstract":"<div><p>Co<sub>3</sub>O<sub>4</sub> with a spinel structure has been utilized as supercapacitor materials due to their active surface sites, strong absorption capacity, excellent electrochemical activity, and stability. In this study, we tried to explore the optimized electrospinning conditions, including heat-treatment temperature for Co<sub>3</sub>O<sub>4</sub> nanofiber fabrication for supercapacitor applications. The X-ray diffraction patterns of Co<sub>3</sub>O<sub>4</sub> nanofibers annealed at 600 and 800 ºC showed a cubic spinel crystal structure without a secondary phase, but CoO was found in the specimens annealed at 400 ºC. From the XPS curve fitting, Co<sup>3+</sup> increased in the Co<sup>3+</sup>/Co<sup>2+</sup> ratio with increasing heat-treatment temperature. The electrical conductivity of the Co<sub>3</sub>O<sub>4</sub> nanofibers heated at 400, 600, and 800 ºC is 7.53 × 10<sup>−3</sup>, 1.12 × 10<sup>−2</sup>, and 6.26 × 10<sup>−3</sup> Ω<sup>−1</sup> cm<sup>−1</sup>, respectively. The Co<sub>3</sub>O<sub>4</sub> nanofibers heat treated at 600 ºC showed the highest conductivity value, and the conduction mechanism was polaron hopping between Co<sup>3+</sup> and Co<sup>2+</sup>. The supercapacitor properties of Co<sub>3</sub>O<sub>4</sub> nanofibers are evaluated by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance measurement using a three-electrode system in a 3 M KOH electrolyte. The GCD tests showed that the Co<sub>3</sub>O<sub>4</sub> nanofibers heated at 600 ºC had the highest specific capacitance of 579.66 F/g. From the electrochemical impedance measurements, the charge transfer resistance (R<sub>ct</sub>) of calcined Co<sub>3</sub>O<sub>4</sub> nanofibers at 600 ºC showed the lowest value of 1.27 Ω. Also, the Co<sub>3</sub>O<sub>4</sub> nanofiber exhibits excellent cycle stability with capacitance retention over 99% until 1000 cycles at a current density of 2 A/g. Therefore, the excellent supercapacitor performance of Co<sub>3</sub>O<sub>4</sub> nanofibers annealed at 600 ºC is due to its nanofiber structure without a secondary phase providing a larger surface area and charge transfer.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"20 1","pages":"78 - 84"},"PeriodicalIF":2.1,"publicationDate":"2023-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135265886","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 : 2023-10-10DOI: 10.1007/s13391-023-00463-y
Jaewook Kim, Jahun Koo, Byungwoo Park, Chunjoong Kim, Chong Rae Park
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Pub Date : 2023-09-28DOI: 10.1007/s13391-023-00460-1
Manikandan Gunasekaran, Dhanalakshmi Dhandapani, Manivel Raja Muthuvel
An organic semiconductor (OSC) is a potential material in spintronics which is posses a long spin diffusion length due to its low spin-orbit coupling and hyperfine interaction. Among the OSC P3HT that already exists, in spintronic devices. In this report, An organic spin valve (OSV) device was fabricated using Regioregular Poly 3-hexylthiophene-2,5- diyl (RR-P3HT). The RR-P3HT was used as a spacer layer, with FeCo and NiFe used as bottom and top electrodes, respectively. The device magnetoresistance (MR) was observed to be a positive MR of 2.9% at 50 K while negative MR of 0.6, 0.4, and 0.014% were observed at 150, 200, and 300 K, respectively. Observed AMR is positive at room temperature for Feco and NiFe single layer as 0.08 and 0.18%, respectively. The magnetic electrodes were prepared using Ultra High Vacuum DC magnetron sputtering, and RR-P3HT was prepared using a spin coater. The magnetic properties of the device were studied by vibrating sample magnetometer (VSM) analysis. The VSM results conclude that both electrodes are magnetic materials with different coercive forces. The FeCo and NiFe, both electrodes crystal structures were analyzed from Gracing Incidence X-Ray Diffraction (GI-XRD) using Cobalt K alpha. FeCo and NiFe were the Body-Centered Cubic crystal structures, and the electrode’s JCPDS card numbers are 50–0795 and 37–0474, respectively.
Graphical Abstract
有机半导体（OSC）是一种潜在的自旋电子学材料，由于其自旋轨道耦合和超细相互作用较低，因此具有较长的自旋扩散长度。在已有的自旋电子器件中，P3HT 是一种有机半导体。在本报告中，我们使用 Regioregular Poly 3-hexylthiophene-2,5- diyl (RR-P3HT) 制作了一个有机自旋阀（OSV）器件。RR-P3HT 用作间隔层，FeCo 和 NiFe 分别用作底部和顶部电极。器件磁阻（MR）在 50 K 时为正 2.9%，而在 150、200 和 300 K 时分别为负 0.6%、0.4% 和 0.014%。在室温下观察到的 Feco 和 NiFe 单层 AMR 分别为 0.08% 和 0.18%。磁电极采用超高真空直流磁控溅射法制备，RR-P3HT 采用旋涂机制备。通过振动样品磁力计（VSM）分析研究了该器件的磁性能。VSM 分析结果表明，两种电极都是具有不同矫顽力的磁性材料。利用钴 K 阿尔法入射 X 射线衍射（GI-XRD）分析了铁钴和镍铁合金这两种电极的晶体结构。FeCo和NiFe为体心立方晶体结构，电极的JCPDS卡号分别为50-0795和37-0474。
{"title":"Spin Route Flipping in FeCo/RR-P3HT/ NiFe Organic Spin-Valve Device","authors":"Manikandan Gunasekaran, Dhanalakshmi Dhandapani, Manivel Raja Muthuvel","doi":"10.1007/s13391-023-00460-1","DOIUrl":"10.1007/s13391-023-00460-1","url":null,"abstract":"<div><p>An organic semiconductor (OSC) is a potential material in spintronics which is posses a long spin diffusion length due to its low spin-orbit coupling and hyperfine interaction. Among the OSC P3HT that already exists, in spintronic devices. In this report, An organic spin valve (OSV) device was fabricated using Regioregular Poly 3-hexylthiophene-2,5- diyl (RR-P3HT). The RR-P3HT was used as a spacer layer, with FeCo and NiFe used as bottom and top electrodes, respectively. The device magnetoresistance (MR) was observed to be a positive MR of 2.9% at 50 K while negative MR of 0.6, 0.4, and 0.014% were observed at 150, 200, and 300 K, respectively. Observed AMR is positive at room temperature for Feco and NiFe single layer as 0.08 and 0.18%, respectively. The magnetic electrodes were prepared using Ultra High Vacuum DC magnetron sputtering, and RR-P3HT was prepared using a spin coater. The magnetic properties of the device were studied by vibrating sample magnetometer (VSM) analysis. The VSM results conclude that both electrodes are magnetic materials with different coercive forces. The FeCo and NiFe, both electrodes crystal structures were analyzed from Gracing Incidence X-Ray Diffraction (GI-XRD) using Cobalt K alpha. FeCo and NiFe were the Body-Centered Cubic crystal structures, and the electrode’s JCPDS card numbers are 50–0795 and 37–0474, respectively.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"20 2","pages":"158 - 164"},"PeriodicalIF":2.1,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135386312","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 : 2023-09-25DOI: 10.1007/s13391-023-00462-z
Jiunan Xie, Hua Hu, Peixin Chen, Han Lei, Anmin Hu, Yunwen Wu, Ming Li
A low-temperature solid-state bonding technology using palladium-coated Co micro-nano cones array (MCA) and Sn-3.0Ag-0.5Cu (wt%) solder was investigated. The Pd modification layer on the surface of Co MCA reduced the growth of oxide film. Low-temperature solid-state bonding was achieved using Co/Pd MCA under the bonding condition of 750 gf, 175 °C and 150 s with the shear strength of 49.55 MPa, and there was no void found along the bonding interface. Microscopic observation revealed that Co/Pd MCA was fully embedded in the soft solder. The average shear strength of the bonding joint was measured and demonstrate that Co/Pd MCA has higher reliability than Co MCA. This work highlights the advantages of bonding based on Co/Pd MCA, which has great potential for extensive practical applications.
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