I. Carrillo-Berdugo, J. J. Gallardo, Nazaret Ruiz-Marín, Violeta Guillén-Domínguez, Rodrigo Alcántara, J. Navas, J. A. Poce-Fatou
This work discusses the applicability of lightweight aggregate-encapsulated n-octadecane with 1.0 wt.% of Cu nanoparticles, for enhanced thermal comfort in buildings by providing thermal energy storage functionality to no-fines concrete. A straightforward two-step procedure (impregnation and occlusion) for the encapsulation of the nano-additivated phase change material in lightweight aggregates is presented. Encapsulation efficiencies of 30–40% are achieved. Phase change behavior is consistent across cycles. Cu nanoparticles provide nucleation points for phase change and increase the rate of progression of phase change fronts due to the enhancement in the effective thermal conductivity of n-octadecane. The effective thermal conductivity of the composites remains like that of regular lightweight aggregates and can still fulfil thermal insulation requirements. The thermal response of no-fines concrete blocks prepared with these new aggregates is also studied. Under artificial sunlight, with a standard 1000 W·m−2 irradiance and AM1.5G filter, concrete samples with the epoxy-coated aggregate-encapsulated n-octadecane-based dispersion of Cu nanoparticles (with a phase change material content below 8% of the total concrete mass) can effectively maintain a significant 5 °C difference between irradiated and non-irradiated sides of the block for ca. 30 min.
{"title":"Thermal Energy Storage in Concrete by Encapsulation of a Nano-Additivated Phase Change Material in Lightweight Aggregates","authors":"I. Carrillo-Berdugo, J. J. Gallardo, Nazaret Ruiz-Marín, Violeta Guillén-Domínguez, Rodrigo Alcántara, J. Navas, J. A. Poce-Fatou","doi":"10.3390/nano14141180","DOIUrl":"https://doi.org/10.3390/nano14141180","url":null,"abstract":"This work discusses the applicability of lightweight aggregate-encapsulated n-octadecane with 1.0 wt.% of Cu nanoparticles, for enhanced thermal comfort in buildings by providing thermal energy storage functionality to no-fines concrete. A straightforward two-step procedure (impregnation and occlusion) for the encapsulation of the nano-additivated phase change material in lightweight aggregates is presented. Encapsulation efficiencies of 30–40% are achieved. Phase change behavior is consistent across cycles. Cu nanoparticles provide nucleation points for phase change and increase the rate of progression of phase change fronts due to the enhancement in the effective thermal conductivity of n-octadecane. The effective thermal conductivity of the composites remains like that of regular lightweight aggregates and can still fulfil thermal insulation requirements. The thermal response of no-fines concrete blocks prepared with these new aggregates is also studied. Under artificial sunlight, with a standard 1000 W·m−2 irradiance and AM1.5G filter, concrete samples with the epoxy-coated aggregate-encapsulated n-octadecane-based dispersion of Cu nanoparticles (with a phase change material content below 8% of the total concrete mass) can effectively maintain a significant 5 °C difference between irradiated and non-irradiated sides of the block for ca. 30 min.","PeriodicalId":508599,"journal":{"name":"Nanomaterials","volume":"112 24","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141657297","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}
We report on the use of 2D Ruddlesden–Popper (RP) perovskites as optoelectronic materials in building-integrated applications, addressing the challenge of balancing transparency, photoluminescence, and stability. With the addition of polyvinylpyrrolidone (PVP), the 2D RP films exhibit superior transparency compared to their 3D counterparts with an average visible transmittance (AVT) greater than 50% and photoluminescence stability under continuous illumination and 85 °C heat for up to 100 h as bare, unencapsulated films. Structural investigations show a stress relaxation in the 3D perovskite films after degradation from thermal aging that is not observed in the 2D RP films, which retain their phase after thermal and light aging. We also demonstrate ultrasmooth, wide-bandgap 2D Dion–Jacobson (DJ) films with PVP incorporation up to 2.95 eV, an AVT above 70%, and roughnesses of ~2 nm. These findings contribute to the development of next-generation solar materials, paving the way for their integration into built structures.
我们报告了二维 Ruddlesden-Popper (RP) 包晶石作为光电材料在建筑集成应用中的应用，解决了平衡透明度、光致发光和稳定性的难题。添加聚乙烯吡咯烷酮（PVP）后，二维 RP 薄膜的透明度优于三维 RP 薄膜，平均可见光透射率（AVT）超过 50%，在连续光照和 85 °C 高温下，光致发光稳定性可达 100 小时，如同未封装的裸膜一样。结构研究表明，热老化降解后的三维包晶薄膜会出现应力松弛，而二维 RP 薄膜则不会出现这种现象。我们还展示了超平滑、宽带隙的二维 Dion-Jacobson (DJ) 薄膜，其 PVP 含量高达 2.95 eV，AVT 超过 70%，粗糙度约为 2 nm。这些发现有助于下一代太阳能材料的开发，为将其集成到建筑结构中铺平了道路。
{"title":"2D Ruddlesden–Popper Perovskites with Polymer Additive as Stable and Transparent Optoelectronic Materials for Building-Integrated Applications","authors":"Adianne Alamban, Muneeza Ahmad, Nicholas Rolston","doi":"10.3390/nano14141184","DOIUrl":"https://doi.org/10.3390/nano14141184","url":null,"abstract":"We report on the use of 2D Ruddlesden–Popper (RP) perovskites as optoelectronic materials in building-integrated applications, addressing the challenge of balancing transparency, photoluminescence, and stability. With the addition of polyvinylpyrrolidone (PVP), the 2D RP films exhibit superior transparency compared to their 3D counterparts with an average visible transmittance (AVT) greater than 50% and photoluminescence stability under continuous illumination and 85 °C heat for up to 100 h as bare, unencapsulated films. Structural investigations show a stress relaxation in the 3D perovskite films after degradation from thermal aging that is not observed in the 2D RP films, which retain their phase after thermal and light aging. We also demonstrate ultrasmooth, wide-bandgap 2D Dion–Jacobson (DJ) films with PVP incorporation up to 2.95 eV, an AVT above 70%, and roughnesses of ~2 nm. These findings contribute to the development of next-generation solar materials, paving the way for their integration into built structures.","PeriodicalId":508599,"journal":{"name":"Nanomaterials","volume":"135 42","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141656376","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}
Transition metal (TM) single-atom catalysts (SACs) have been widely applied in photocatalytic CO2 reduction. In this work, n–p codoping engineering is introduced to account for the modulation of photocatalytic CO2 reduction on a two-dimensional (2D) bismuth-oxyhalide-based cathode by using first-principles calculation. n–p codoping is established via the Coulomb interactions between the negatively charged TM SACs and the positively charged Cl vacancy (VCl) in the dopant–defect pairs. Based on the formation energy of charged defects, neutral dopant–defect pairs for the Fe, Co, and Ni SACs (PTM0) and the −1e charge state of the Cu SAC-based pair (PCu−1) are stable. The electrostatic attraction of the n–p codoping strengthens the stability and solubility of TM SACs by neutralizing the oppositely charged VCl defect and TM dopant. The n–p codoping stabilizes the electron accumulation around the TM SACs. Accumulated electrons modify the d-orbital alignment and shift the d-band center toward the Fermi level, enhancing the reducing capacity of TM SACs based on the d-band theory. Besides the electrostatic attraction of the n–p codoping, the PCu−1 also accumulates additional electrons surrounding Cu SACs and forms a half-occupied dx2−y2 state, which further upshifts the d-band center and improves photocatalytic CO2 reduction. The metastability of Cl multivacancies limits the concentration of the n–p pairs with Cl multivacancies (PTM@nCl (n > 1)). Positively charged centers around the PTM@nCl (n > 1) hinders the CO2 reduction by shielding the charge transfer to the CO2 molecule.
过渡金属（TM）单原子催化剂（SAC）已广泛应用于光催化二氧化碳还原。本研究通过第一原理计算，引入了正负掺杂工程，以解释二维（2D）双铋氧卤化物基阴极上光催化还原 CO2 的调制。正负掺杂是通过带负电的 TM SAC 与掺杂剂-缺陷对中带正电的 Cl 空位（VCl）之间的库仑相互作用而建立的。根据带电缺陷的形成能，Fe、Co 和 Ni SAC 的中性掺杂剂-缺陷对（PTM0）以及基于 Cu SAC 的-1e 电荷态对（PCu-1）是稳定的。n-p 编码掺杂的静电吸引力通过中和带相反电荷的 VCl 缺陷和 TM 掺杂，增强了 TM SAC 的稳定性和可溶性。n-p 编码掺杂稳定了 TM SAC 周围的电子积累。积累的电子改变了 d 轨道的排列，并使 d 带中心向费米级移动，从而提高了基于 d 带理论的 TM SAC 的还原能力。除了 n-p codoping 的静电吸引外，PCu-1 还在 Cu SACs 周围积累了额外的电子，形成了半占位的 dx2-y2 态，从而进一步上移了 d 带中心，提高了光催化还原 CO2 的能力。Cl 多空位的逸散性限制了带有 Cl 多空位的 n 对的浓度（PTM@nCl（n > 1））。PTM@nCl (n > 1) 周围带正电的中心会屏蔽电荷转移到 CO2 分子，从而阻碍 CO2 还原。
{"title":"Modulation of Photocatalytic CO2 Reduction by n–p Codoping Engineering of Single-Atom Catalysts","authors":"Guowei Yin, Chunxiao Zhang, Yundan Liu, Yuping Sun, Xiang Qi","doi":"10.3390/nano14141183","DOIUrl":"https://doi.org/10.3390/nano14141183","url":null,"abstract":"Transition metal (TM) single-atom catalysts (SACs) have been widely applied in photocatalytic CO2 reduction. In this work, n–p codoping engineering is introduced to account for the modulation of photocatalytic CO2 reduction on a two-dimensional (2D) bismuth-oxyhalide-based cathode by using first-principles calculation. n–p codoping is established via the Coulomb interactions between the negatively charged TM SACs and the positively charged Cl vacancy (VCl) in the dopant–defect pairs. Based on the formation energy of charged defects, neutral dopant–defect pairs for the Fe, Co, and Ni SACs (PTM0) and the −1e charge state of the Cu SAC-based pair (PCu−1) are stable. The electrostatic attraction of the n–p codoping strengthens the stability and solubility of TM SACs by neutralizing the oppositely charged VCl defect and TM dopant. The n–p codoping stabilizes the electron accumulation around the TM SACs. Accumulated electrons modify the d-orbital alignment and shift the d-band center toward the Fermi level, enhancing the reducing capacity of TM SACs based on the d-band theory. Besides the electrostatic attraction of the n–p codoping, the PCu−1 also accumulates additional electrons surrounding Cu SACs and forms a half-occupied dx2−y2 state, which further upshifts the d-band center and improves photocatalytic CO2 reduction. The metastability of Cl multivacancies limits the concentration of the n–p pairs with Cl multivacancies (PTM@nCl (n > 1)). Positively charged centers around the PTM@nCl (n > 1) hinders the CO2 reduction by shielding the charge transfer to the CO2 molecule.","PeriodicalId":508599,"journal":{"name":"Nanomaterials","volume":"80 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141655318","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}
L. Gence, Franck Quero, Miguel Escalona, Robert Wheatley, Birger Seifert, Donovan Diaz-Droguett, M. J. Retamal, Sascha Wallentowitz, U. Volkmann, Heman Bhuyan
In this study, we present a novel method for fabricating semi-transparent electrodes by combining silver nanowires (AgNW) with titanium nitride (TiN) layers, resulting in conductive nanocomposite coatings with exceptional electromechanical properties. These nanocomposites were deposited on cellulose nanopaper (CNP) using a plasma-enhanced pulsed laser deposition (PE-PLD) technique at low temperatures (below 200 ∘C). Repetitive bending tests demonstrate that incorporating AgNW into TiN coatings significantly enhances the microstructure, increasing the electrode’s electromechanical robustness by up to four orders of magnitude compared to commercial PET/ITO substrates. Furthermore, the optical and electrical conductivities can be optimized by adjusting the AgNW network density and TiN synthesis temperature. Our results also indicate that the nanocomposite electrodes exhibit improved stability in air and superior adhesion compared to bare AgNW coatings.
在本研究中，我们提出了一种制造半透明电极的新方法，将银纳米线（AgNW）与氮化钛（TiN）层结合在一起，制成具有优异机电特性的导电纳米复合涂层。这些纳米复合材料采用等离子体增强脉冲激光沉积（PE-PLD）技术，在低温（低于 200 ∘C）下沉积在纤维素纳米纸（CNP）上。重复弯曲测试表明，在 TiN 涂层中加入 AgNW 能显著增强微观结构，与商用 PET/ITO 基底相比，电极的机电稳健性最多可提高四个数量级。此外，还可以通过调整 AgNW 网络密度和 TiN 合成温度来优化光导率和电导率。我们的研究结果还表明，与裸 AgNW 涂层相比，纳米复合电极在空气中表现出更高的稳定性和更优越的附着力。
{"title":"Wrinkled TiNAgNW Nanocomposites for High-Performance Flexible Electrodes on TEMPO-Oxidized Nanocellulose","authors":"L. Gence, Franck Quero, Miguel Escalona, Robert Wheatley, Birger Seifert, Donovan Diaz-Droguett, M. J. Retamal, Sascha Wallentowitz, U. Volkmann, Heman Bhuyan","doi":"10.3390/nano14141178","DOIUrl":"https://doi.org/10.3390/nano14141178","url":null,"abstract":"In this study, we present a novel method for fabricating semi-transparent electrodes by combining silver nanowires (AgNW) with titanium nitride (TiN) layers, resulting in conductive nanocomposite coatings with exceptional electromechanical properties. These nanocomposites were deposited on cellulose nanopaper (CNP) using a plasma-enhanced pulsed laser deposition (PE-PLD) technique at low temperatures (below 200 ∘C). Repetitive bending tests demonstrate that incorporating AgNW into TiN coatings significantly enhances the microstructure, increasing the electrode’s electromechanical robustness by up to four orders of magnitude compared to commercial PET/ITO substrates. Furthermore, the optical and electrical conductivities can be optimized by adjusting the AgNW network density and TiN synthesis temperature. Our results also indicate that the nanocomposite electrodes exhibit improved stability in air and superior adhesion compared to bare AgNW coatings.","PeriodicalId":508599,"journal":{"name":"Nanomaterials","volume":"7 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141661645","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}
Hang Xu, Ping Yu, R. Bandari, Charles J. Smith, Michael R. Aro, Amolak Singh, Lixin Ma
We developed a novel site-specific bimodal MRI/fluorescence nanoparticle contrast agent targeting gastrin-releasing peptide receptors (GRPrs), which are overexpressed in aggressive prostate cancers. Biocompatible ultra-small superparamagnetic iron oxide (USPIO) nanoparticles were synthesized using glucose and casein coatings, followed by conjugation with a Cy7.5-K-8AOC-BBN [7-14] peptide conjugate. The resulting USPIO(Cy7.5)-BBN nanoparticles were purified by 100 kDa membrane dialysis and fully characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier transform infrared (FTIR) spectroscopy, and magnetic resonance imaging (MRI) relaxivity, as well as evaluated for in vitro and in vivo binding specificity and imaging efficacy in PC-3 prostate cancer cells and xenografted tumor-bearing mice. The USPIO(Cy7.5)-BBN nanoparticles had a core diameter of 4.93 ± 0.31 nm and a hydrodynamic diameter of 35.56 ± 0.58 nm. The r2 relaxivity was measured to be 70.2 ± 2.5 s−1 mM−1 at 7T MRI. The Cy7.5-K-8AOC-BBN [7-14] peptide-to-nanoparticle ratio was determined to be 21:1. The in vitro GRPr inhibitory binding (IC50) value was 2.5 ± 0.7 nM, indicating a very high binding affinity of USPIO(Cy7.5)-BBN to the GRPr on PC-3 cells. In vivo MRI showed significant tumor-to-muscle contrast enhancement in the uptake group at 4 h (31.1 ± 3.4%) and 24 h (25.7 ± 2.1%) post-injection compared to the blocking group (4 h: 15.3 ± 2.0% and 24 h: −2.8 ± 6.8%; p < 0.005). In vivo and ex vivo near-infrared fluorescence (NIRF) imaging revealed significantly increased fluorescence in tumors in the uptake group compared to the blocking group. These findings demonstrate the high specificity of bimodal USPIO(Cy7.5)-BBN nanoparticles towards GRPr-expressing PC-3 cells, suggesting their potential for targeted imaging in aggressive prostate cancer.
{"title":"Bimodal MRI/Fluorescence Nanoparticle Imaging Contrast Agent Targeting Prostate Cancer","authors":"Hang Xu, Ping Yu, R. Bandari, Charles J. Smith, Michael R. Aro, Amolak Singh, Lixin Ma","doi":"10.3390/nano14141177","DOIUrl":"https://doi.org/10.3390/nano14141177","url":null,"abstract":"We developed a novel site-specific bimodal MRI/fluorescence nanoparticle contrast agent targeting gastrin-releasing peptide receptors (GRPrs), which are overexpressed in aggressive prostate cancers. Biocompatible ultra-small superparamagnetic iron oxide (USPIO) nanoparticles were synthesized using glucose and casein coatings, followed by conjugation with a Cy7.5-K-8AOC-BBN [7-14] peptide conjugate. The resulting USPIO(Cy7.5)-BBN nanoparticles were purified by 100 kDa membrane dialysis and fully characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier transform infrared (FTIR) spectroscopy, and magnetic resonance imaging (MRI) relaxivity, as well as evaluated for in vitro and in vivo binding specificity and imaging efficacy in PC-3 prostate cancer cells and xenografted tumor-bearing mice. The USPIO(Cy7.5)-BBN nanoparticles had a core diameter of 4.93 ± 0.31 nm and a hydrodynamic diameter of 35.56 ± 0.58 nm. The r2 relaxivity was measured to be 70.2 ± 2.5 s−1 mM−1 at 7T MRI. The Cy7.5-K-8AOC-BBN [7-14] peptide-to-nanoparticle ratio was determined to be 21:1. The in vitro GRPr inhibitory binding (IC50) value was 2.5 ± 0.7 nM, indicating a very high binding affinity of USPIO(Cy7.5)-BBN to the GRPr on PC-3 cells. In vivo MRI showed significant tumor-to-muscle contrast enhancement in the uptake group at 4 h (31.1 ± 3.4%) and 24 h (25.7 ± 2.1%) post-injection compared to the blocking group (4 h: 15.3 ± 2.0% and 24 h: −2.8 ± 6.8%; p < 0.005). In vivo and ex vivo near-infrared fluorescence (NIRF) imaging revealed significantly increased fluorescence in tumors in the uptake group compared to the blocking group. These findings demonstrate the high specificity of bimodal USPIO(Cy7.5)-BBN nanoparticles towards GRPr-expressing PC-3 cells, suggesting their potential for targeted imaging in aggressive prostate cancer.","PeriodicalId":508599,"journal":{"name":"Nanomaterials","volume":"1 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141658644","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}
Strain-free GaAs cone-shell quantum dots have a unique shape, which allows a wide tunability of the charge-carrier probability densities by external electric and magnetic fields. Here, the influence of a lateral electric field on the optical emission is studied experimentally using simulations. The simulations predict that the electron and hole form a lateral dipole when subjected to a lateral electric field. To evaluate this prediction experimentally, we integrate the dots in a lateral gate geometry and measure the Stark-shift of the exciton energy, the exciton intensity, the radiative lifetime, and the fine-structure splitting (FSS) using single-dot photoluminescence spectroscopy. The respective gate voltage dependencies show nontrivial trends with three pronounced regimes. We assume that the respective dominant processes are charge-carrier deformation at a low gate voltage U, a vertical charge-carrier shift at medium U, and a lateral charge-carrier polarization at high U. The lateral polarization forms a dipole, which can either enhance or compensate the intrinsic FSS induced by the QD shape anisotropy, dependent on the in-plane orientation of the electric field. Furthermore, the data show that the biexciton peak can be suppressed by a lateral gate voltage, and we assume the presence of an additional vertical electric field induced by surface charges.
无应变砷化镓锥壳量子点具有独特的形状，可通过外部电场和磁场对电荷载流子概率密度进行广泛的调节。本文通过模拟实验研究了横向电场对光发射的影响。模拟预测电子和空穴在横向电场作用下会形成横向偶极子。为了在实验中评估这一预测，我们在横向栅极几何中整合了点，并使用单点光致发光光谱法测量了激子能量的星移、激子强度、辐射寿命和精细结构分裂（FSS）。各自的栅极电压依赖性呈现出非对称的趋势，有三种明显的状态。我们假设各自的主导过程分别是低栅极电压 U 下的电荷载流子变形、中等 U 下的垂直电荷载流子偏移和高 U 下的横向电荷载流子极化。横向极化形成一个偶极子，它可以增强或补偿由 QD 形状各向异性诱导的固有 FSS，这取决于电场的面内取向。此外，数据还显示，双激子峰值可被横向栅极电压抑制，我们假设存在由表面电荷诱导的额外垂直电场。
{"title":"GaAs Cone-Shell Quantum Dots in a Lateral Electric Field: Exciton Stark-Shift, Lifetime, and Fine-Structure Splitting","authors":"Ahmed Alshaikh, R. Blick, Christian Heyn","doi":"10.3390/nano14141174","DOIUrl":"https://doi.org/10.3390/nano14141174","url":null,"abstract":"Strain-free GaAs cone-shell quantum dots have a unique shape, which allows a wide tunability of the charge-carrier probability densities by external electric and magnetic fields. Here, the influence of a lateral electric field on the optical emission is studied experimentally using simulations. The simulations predict that the electron and hole form a lateral dipole when subjected to a lateral electric field. To evaluate this prediction experimentally, we integrate the dots in a lateral gate geometry and measure the Stark-shift of the exciton energy, the exciton intensity, the radiative lifetime, and the fine-structure splitting (FSS) using single-dot photoluminescence spectroscopy. The respective gate voltage dependencies show nontrivial trends with three pronounced regimes. We assume that the respective dominant processes are charge-carrier deformation at a low gate voltage U, a vertical charge-carrier shift at medium U, and a lateral charge-carrier polarization at high U. The lateral polarization forms a dipole, which can either enhance or compensate the intrinsic FSS induced by the QD shape anisotropy, dependent on the in-plane orientation of the electric field. Furthermore, the data show that the biexciton peak can be suppressed by a lateral gate voltage, and we assume the presence of an additional vertical electric field induced by surface charges.","PeriodicalId":508599,"journal":{"name":"Nanomaterials","volume":"21 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141659758","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}
Environmental pollution of phosphorus is becoming increasingly concerning, and phosphate removal from water has become an important issue for controlling eutrophication. Modified metal–organic framework (MOF) materials, such as UiO-66-NH2, are promising adsorbents for phosphate removal in aquatic environments due to their high specific surface area, high porosity, and open active metal sites. In this study, a millimeter-sized alginate/UiO-66-NH2 composite hydrogel modified by polyethyleneimine (UiO-66-NH2/SA@PEI) was prepared. The entrapping of UiO-66-NH2 in the alginate microspheres and its modification with PEI facilitate easy separation in addition to enhanced adsorption properties. The materials were characterized by SEM, FTIR, XRD, and BET. Static, dynamic, and cyclic adsorption experiments were conducted under different pH, temperature, adsorbent dosage, and initial concentration conditions to assess the phosphate adsorption ability of UiO-66-NH2/SA@PEI. Under optimal conditions of 65 °C and pH = 2, 0.05 g UiO-66-NH2/SA@PEI adsorbed 68.75 mg/g, and the adsorption rate remained at 99% after five cycles of UiO-66-NH2/SA@PEI. These results suggest that UiO-66-NH2/SA@PEI composite materials can be used as an effective adsorbent for phosphate removal from wastewater.
{"title":"Sodium Alginate/UiO-66-NH2 Nanocomposite for Phosphate Removal","authors":"Xiaohang Lin, Yuzhu Xiong, Fuping Dong","doi":"10.3390/nano14141176","DOIUrl":"https://doi.org/10.3390/nano14141176","url":null,"abstract":"Environmental pollution of phosphorus is becoming increasingly concerning, and phosphate removal from water has become an important issue for controlling eutrophication. Modified metal–organic framework (MOF) materials, such as UiO-66-NH2, are promising adsorbents for phosphate removal in aquatic environments due to their high specific surface area, high porosity, and open active metal sites. In this study, a millimeter-sized alginate/UiO-66-NH2 composite hydrogel modified by polyethyleneimine (UiO-66-NH2/SA@PEI) was prepared. The entrapping of UiO-66-NH2 in the alginate microspheres and its modification with PEI facilitate easy separation in addition to enhanced adsorption properties. The materials were characterized by SEM, FTIR, XRD, and BET. Static, dynamic, and cyclic adsorption experiments were conducted under different pH, temperature, adsorbent dosage, and initial concentration conditions to assess the phosphate adsorption ability of UiO-66-NH2/SA@PEI. Under optimal conditions of 65 °C and pH = 2, 0.05 g UiO-66-NH2/SA@PEI adsorbed 68.75 mg/g, and the adsorption rate remained at 99% after five cycles of UiO-66-NH2/SA@PEI. These results suggest that UiO-66-NH2/SA@PEI composite materials can be used as an effective adsorbent for phosphate removal from wastewater.","PeriodicalId":508599,"journal":{"name":"Nanomaterials","volume":"25 17","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141662414","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}
The rapid progress of flexible electronics has met the growing need for detecting human movement information in exoskeleton auxiliary equipment. This study provides a review of recent advancements in the design and fabrication of flexible electronics used for human motion detection. Firstly, a comprehensive introduction is provided on various self-powered wearable flexible sensors employed in detecting human movement information. Subsequently, the algorithms utilized to provide feedback on human movement are presented, followed by a thorough discussion of their methods and effectiveness. Finally, the review concludes with perspectives on the current challenges and opportunities in implementing self-powered wearable flexible sensors in exoskeleton technology.
{"title":"Recent Advances in Self-Powered Wearable Flexible Sensors for Human Gaits Analysis","authors":"Xiaohe Hu, Zhiqiang Ma, Fuqun Zhao, Sheng Guo","doi":"10.3390/nano14141173","DOIUrl":"https://doi.org/10.3390/nano14141173","url":null,"abstract":"The rapid progress of flexible electronics has met the growing need for detecting human movement information in exoskeleton auxiliary equipment. This study provides a review of recent advancements in the design and fabrication of flexible electronics used for human motion detection. Firstly, a comprehensive introduction is provided on various self-powered wearable flexible sensors employed in detecting human movement information. Subsequently, the algorithms utilized to provide feedback on human movement are presented, followed by a thorough discussion of their methods and effectiveness. Finally, the review concludes with perspectives on the current challenges and opportunities in implementing self-powered wearable flexible sensors in exoskeleton technology.","PeriodicalId":508599,"journal":{"name":"Nanomaterials","volume":"51 17","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141660068","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}
Organic–inorganic nanocomposites have the potential to be used in photovoltaic materials due to their eco-friendliness, suitable band gaps, and high stability. In this work, we integrated gold and Fe3O4 magnetic nanoparticles with poly-m-amino benzene sulfonic (m-ABS) to synthesize Fe3O4@Au@poly-(m-aminobenzenesulfonic acid) (Fe3O4@Au@m-ABS) magneto-plasmonic nanoparticles (MPNPs) to enhance the performance of the organic photovoltaic (OPV). These MPNPs exhibit broad UV-Vis absorption and a low band gap of 2.878 eV, enhancing their suitability for photovoltaic applications. The MPNPs were introduced into the ZnO electron transporting layer (ETL) and active layer to investigate the influence of MPNPs on the power conversion efficiency (PCE) of the OPVs. When 0.1 vol% MPNPs were incorporated in the ETL, the OPVs achieved a PCE of 14.24% and a fill factor (FF) of 69.10%. On the other hand, when 0.1 vol% MPNPs were incorporated in the active layer, the OPVs showed a PCE of 14.11% and an FF of 68.83%. However, the OPVs without MPNPs only possessed a PCE of 13.15% and an FF of 63.69%. The incorporation of MPNPs increased the PCE by 8.3% in the OPV device. These findings suggest that Fe3O4@Au@m-ABS MPNPs are promising nanocomposite materials for enhancing the performance of OPVs.
{"title":"Enhancing Power Conversion Efficiency of Organic Solar Cells with Magnetoplasmonic Fe3O4@Au@m-ABS Nanoparticles","authors":"Pradeep Kumar, Shih-Han Huang, Chia-Yi Hsu, Ssu-Yung Chung, H. Cha, Chih-Min Chuang, Kuen-Lin Chen, Yu-Ching Huang","doi":"10.3390/nano14141175","DOIUrl":"https://doi.org/10.3390/nano14141175","url":null,"abstract":"Organic–inorganic nanocomposites have the potential to be used in photovoltaic materials due to their eco-friendliness, suitable band gaps, and high stability. In this work, we integrated gold and Fe3O4 magnetic nanoparticles with poly-m-amino benzene sulfonic (m-ABS) to synthesize Fe3O4@Au@poly-(m-aminobenzenesulfonic acid) (Fe3O4@Au@m-ABS) magneto-plasmonic nanoparticles (MPNPs) to enhance the performance of the organic photovoltaic (OPV). These MPNPs exhibit broad UV-Vis absorption and a low band gap of 2.878 eV, enhancing their suitability for photovoltaic applications. The MPNPs were introduced into the ZnO electron transporting layer (ETL) and active layer to investigate the influence of MPNPs on the power conversion efficiency (PCE) of the OPVs. When 0.1 vol% MPNPs were incorporated in the ETL, the OPVs achieved a PCE of 14.24% and a fill factor (FF) of 69.10%. On the other hand, when 0.1 vol% MPNPs were incorporated in the active layer, the OPVs showed a PCE of 14.11% and an FF of 68.83%. However, the OPVs without MPNPs only possessed a PCE of 13.15% and an FF of 63.69%. The incorporation of MPNPs increased the PCE by 8.3% in the OPV device. These findings suggest that Fe3O4@Au@m-ABS MPNPs are promising nanocomposite materials for enhancing the performance of OPVs.","PeriodicalId":508599,"journal":{"name":"Nanomaterials","volume":"9 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141661156","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}
To improve the wear resistance of the materials used for blades in engineering machinery, this study focused on the microstructural characteristics, mechanical properties, and wear behavior of HB500 grade wear-resistant steel developed using an optimized heat treatment system. To improve the temperature uniformity of the heat treatment furnace, the method of cyclic heating was used to heat the components. Carefully designing the quenching equipment, such as using a cross-shaped press, was employed to enhance the quenching effect and reduce the deformation of the steel plates. The crystal orientation analysis revealed a uniform and fine-grained microstructure, primarily characterized by plate-type tempered martensite, which indicated a good hardenability. The microstructure observations showed that the width of martensite is approximately 200 nm, with a significant presence of dislocations and carbides. Tensile tests and multi-temperature gradient impact tests indicated superior mechanical properties compared to similar grade wear-resistant steels, including a Rockwell hardness of 53, tensile strength of 1610 MPa, yield strength of 1404 MPa, and total elongation around 12.7%. The results of friction and wear experiments indicate that the wear rate decreases as the load increases from 100 N to 300 N, demonstrating an excellent wear resistance under a large load. Observations of the worn surfaces indicated that the wear mainly involved adhesive wear, fatigue wear, and oxidative wear. The properties’ improvements were attributed to microstructure refinement and precipitation strengthening. This study indicates that designing a heat treatment system to control temperature uniformity and stability is feasible.
为提高工程机械叶片材料的耐磨性，本研究重点关注了采用优化热处理系统开发的 HB500 级耐磨钢的微观结构特征、机械性能和磨损行为。为了提高热处理炉的温度均匀性，采用了循环加热的方法对部件进行加热。对淬火设备进行了精心设计，如使用十字形压力机，以提高淬火效果并减少钢板变形。晶体取向分析表明，钢板的微观结构均匀且颗粒细小，主要特征是板型回火马氏体，这表明钢板具有良好的淬透性。显微结构观察结果表明，马氏体的宽度约为 200 nm，其中存在大量位错和碳化物。拉伸试验和多温度梯度冲击试验表明，与同类耐磨钢相比，该耐磨钢具有更优越的机械性能，包括洛氏硬度 53、抗拉强度 1610 兆帕、屈服强度 1404 兆帕和约 12.7% 的总伸长率。摩擦和磨损实验结果表明，当载荷从 100 N 增加到 300 N 时，磨损率降低，这表明在大载荷下具有出色的耐磨性。对磨损表面的观察表明，磨损主要涉及粘着磨损、疲劳磨损和氧化磨损。性能的改善归因于微观结构的细化和沉淀强化。这项研究表明，设计一个热处理系统来控制温度的均匀性和稳定性是可行的。
{"title":"Study of the Effects on the Strengthening Mechanism and Wear Behavior of Wear-Resistant Steel of Temperature Controlling in Heat Treatment","authors":"Xiaoyu Zhu, J. Lin, Shaoning Jiang, Aijun Cao, Yuan Yao, Yu Sun, Sensen Li, Zhanfeng Zhang","doi":"10.3390/nano14141171","DOIUrl":"https://doi.org/10.3390/nano14141171","url":null,"abstract":"To improve the wear resistance of the materials used for blades in engineering machinery, this study focused on the microstructural characteristics, mechanical properties, and wear behavior of HB500 grade wear-resistant steel developed using an optimized heat treatment system. To improve the temperature uniformity of the heat treatment furnace, the method of cyclic heating was used to heat the components. Carefully designing the quenching equipment, such as using a cross-shaped press, was employed to enhance the quenching effect and reduce the deformation of the steel plates. The crystal orientation analysis revealed a uniform and fine-grained microstructure, primarily characterized by plate-type tempered martensite, which indicated a good hardenability. The microstructure observations showed that the width of martensite is approximately 200 nm, with a significant presence of dislocations and carbides. Tensile tests and multi-temperature gradient impact tests indicated superior mechanical properties compared to similar grade wear-resistant steels, including a Rockwell hardness of 53, tensile strength of 1610 MPa, yield strength of 1404 MPa, and total elongation around 12.7%. The results of friction and wear experiments indicate that the wear rate decreases as the load increases from 100 N to 300 N, demonstrating an excellent wear resistance under a large load. Observations of the worn surfaces indicated that the wear mainly involved adhesive wear, fatigue wear, and oxidative wear. The properties’ improvements were attributed to microstructure refinement and precipitation strengthening. This study indicates that designing a heat treatment system to control temperature uniformity and stability is feasible.","PeriodicalId":508599,"journal":{"name":"Nanomaterials","volume":"5 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141665369","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：