Pub Date : 2024-10-21DOI: 10.1016/j.optmat.2024.116279
P.K. Nideesh , R. Antoine , N. Kalarikkal
This article extends our previous investigation into random lasers (RLs), focusing on the incorporation of Rhodamine 6G (R6G) dye in methanol with Kaolinite nanoclay scatterers as a disordered active medium for colloidal RLs. Building upon the prior exploration, which specifically focused on understanding the performance dependence related to the concentration of gain medium and scatterers, this report takes a closer look. It conducts a thorough statistical analysis of the incoherent dye-Kaolinite random lasing spectra, particularly in the context of replica symmetry breaking (RSB) and Lévy statistics. This study highlights that RSB is observed around the threshold energy and can serve as an indicator of the threshold. Gaussian distribution prevailed below, near, and far above the lasing threshold estimated from the levy () exponent, suggesting the absence of Lévy flight behavior. Additionally, Pearson correlation coefficients (PCC) were used to quantify the correlation between intensity fluctuations at different wavelengths, with the results visually represented by heatmaps. Furthermore, the random lasing output is utilized to achieve speckle-free imaging.
{"title":"Exploring statistical complexity and enabling speckle-free imaging with Dye-Kaolinite colloidal random lasers","authors":"P.K. Nideesh , R. Antoine , N. Kalarikkal","doi":"10.1016/j.optmat.2024.116279","DOIUrl":"10.1016/j.optmat.2024.116279","url":null,"abstract":"<div><div>This article extends our previous investigation into random lasers (RLs), focusing on the incorporation of Rhodamine 6G (R6G) dye in methanol with Kaolinite nanoclay scatterers as a disordered active medium for colloidal RLs. Building upon the prior exploration, which specifically focused on understanding the performance dependence related to the concentration of gain medium and scatterers, this report takes a closer look. It conducts a thorough statistical analysis of the incoherent dye-Kaolinite random lasing spectra, particularly in the context of replica symmetry breaking (RSB) and Lévy statistics. This study highlights that RSB is observed around the threshold energy and can serve as an indicator of the threshold. Gaussian distribution prevailed below, near, and far above the lasing threshold estimated from the levy (<span><math><mi>α</mi></math></span>) exponent, suggesting the absence of Lévy flight behavior. Additionally, Pearson correlation coefficients (PCC) were used to quantify the correlation between intensity fluctuations at different wavelengths, with the results visually represented by heatmaps. Furthermore, the random lasing output is utilized to achieve speckle-free imaging.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"157 ","pages":"Article 116279"},"PeriodicalIF":3.8,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study involved the synthesis of modified ZnO materials for photoelectrocatalysis (PEC) by a simple and environmentally friendly electrochemical procedure. The objective was to assess their capacity to photochemically breakdown ofloxacin (OFX) in an aqueous solution. To enhance the PEC performance of pure ZnO, a zinc oxide–reduced graphene oxide (ZnO–rGO) composite was synthesized through an electrochemical co-deposition process without the use of a reducing agent. Subsequently, ZnO–rGO was doped with N (ZnO–rGO:N) to further augment the PEC performance of the photoanode. The surface morphology, microstructure, and optical characteristics of the materials were systematically investigated through X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and UV–visible spectroscopy. The parameters for synthesizing ZnO–rGO were optimized based on the experimental results” if it can more simply convey your intended meaning. Electrochemical tests demonstrated that N-doping significantly enhanced the photocurrent density of the ZnO–rGO films, which reached 15.14 μA cm−2, representing 1.6- and 1.3-fold enhancements with respect to those of pure ZnO (9.25 μA cm−2) and ZnO–rGO (12.0 μA cm−2), respectively. Additionally, the band gap in ZnO was narrowed from 3.4 to 3.18 eV owing to rGO co-deposition and N-doping. After 180 min of Xe lamp irradiation, with a bias potential of 0.7 V (referenced to Ag/AgCl), ZnO–rGO:N demonstrated an OFX degradation rate of 55.7 %. Thus, the N-doped material exhibited higher PEC performance than either ZnO (31.8 %) or ZnO–rGO (36.3 %), implying its enhanced PEC capabilities. Therefore, the modified ZnO-based photoanode prepared using the straightforward electrochemical deposition method satisfied the objective of this study, which was to enhance its PEC activity while providing a viable foundation for nitrogen doping through electrochemical methods.
{"title":"Novel electrochemical synthesis of N-doped ZnO–rGO films for the photoelectrocatalytic degradation of antibiotics","authors":"Shutong Chen, Xiaosan Song, Xichen Song, Yue Zhang","doi":"10.1016/j.optmat.2024.116308","DOIUrl":"10.1016/j.optmat.2024.116308","url":null,"abstract":"<div><div>This study involved the synthesis of modified ZnO materials for photoelectrocatalysis (PEC) by a simple and environmentally friendly electrochemical procedure. The objective was to assess their capacity to photochemically breakdown ofloxacin (OFX) in an aqueous solution. To enhance the PEC performance of pure ZnO, a zinc oxide–reduced graphene oxide (ZnO–rGO) composite was synthesized through an electrochemical co-deposition process without the use of a reducing agent. Subsequently, ZnO–rGO was doped with N (ZnO–rGO:N) to further augment the PEC performance of the photoanode. The surface morphology, microstructure, and optical characteristics of the materials were systematically investigated through X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and UV–visible spectroscopy. The parameters for synthesizing ZnO–rGO were optimized based on the experimental results” if it can more simply convey your intended meaning. Electrochemical tests demonstrated that N-doping significantly enhanced the photocurrent density of the ZnO–rGO films, which reached 15.14 μA cm<sup>−2</sup>, representing 1.6- and 1.3-fold enhancements with respect to those of pure ZnO (9.25 μA cm<sup>−2</sup>) and ZnO–rGO (12.0 μA cm<sup>−2</sup>), respectively. Additionally, the band gap in ZnO was narrowed from 3.4 to 3.18 eV owing to rGO co-deposition and N-doping. After 180 min of Xe lamp irradiation, with a bias potential of 0.7 V (referenced to Ag/AgCl), ZnO–rGO:N demonstrated an OFX degradation rate of 55.7 %. Thus, the N-doped material exhibited higher PEC performance than either ZnO (31.8 %) or ZnO–rGO (36.3 %), implying its enhanced PEC capabilities. Therefore, the modified ZnO-based photoanode prepared using the straightforward electrochemical deposition method satisfied the objective of this study, which was to enhance its PEC activity while providing a viable foundation for nitrogen doping through electrochemical methods.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"157 ","pages":"Article 116308"},"PeriodicalIF":3.8,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-20DOI: 10.1016/j.optmat.2024.116299
Ni Wang , Linye Zhang , Guangxiang Duan , Wen Wang , Yanling Zhou , Guangtao Wei , Deyuan Xiong , Huanrong Wang , Xinlan Huang
An efficient TiO2/ARM(2:1) catalyst was prepared by sol-gel method, in which the ratio of TiO2 to ARM was 2:1, and the prepared TiO2/ARM(2:1) catalyst was utilized to activate peroxymonosulfate (PMS) for the degradation of metronidazole (MET). X-ray diffractometry (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) analyses showed that the pore volume, pore diameter, and specific surface area of RM were significantly increased by acidification. Acidified RM provided more loading space for TiO2, allowing more TiO2 to be dispersed on the RM surface and in the pore interstitials. The TiO2/ARM(2:1) composite could expose more highly reactive components, thereby increasing the catalytic activity of the catalyst. X-ray photoelectron spectroscopy (XPS) and electrochemical analyses demonstrated the excellent activity of TiO2/ARM(2:1) composite in separating and transferring photoinduced electrons and holes. Approximately, 91.0 % of MET (10 mg/L) was decomposed at 60 min under the optimal reaction conditions of the TiO2/ARM(2:1) catalyst [TiO2/ARM(2:1)] = 0.05 g/L, [PMS] = 3 mM, and the pH of 5.9. The results of the quenching experiments indicated that the •O2−, 1O2 and h+ were the main reactive species responsible for the degradation of MET in the TiO2/ARM(2:1)/PMS/vis system. The possible degradation pathways of MET were proposed through Density-Functional Theory (DFT) calculations and liquid chromatography-mass spectrometry (LC-MS). Results. The prediction results of the Toxicity Evaluation Software Tool (T.E.S.T) suggested that the toxicity of MET was effectively reduced after treatment in the TiO2/ARM(2:1)/PMS/vis system. After five cycling experiments, TiO2/ARM (2:1) showed excellent stability. This work provided a new perspective on the modification of industrial waste RM applied in the direction of catalysis.
{"title":"Insight into peroxymonosulfate-assisted photocatalysis over acidified red mud-supported TiO2 composite for highly efficient degradation of metronidazole","authors":"Ni Wang , Linye Zhang , Guangxiang Duan , Wen Wang , Yanling Zhou , Guangtao Wei , Deyuan Xiong , Huanrong Wang , Xinlan Huang","doi":"10.1016/j.optmat.2024.116299","DOIUrl":"10.1016/j.optmat.2024.116299","url":null,"abstract":"<div><div>An efficient TiO<sub>2</sub>/ARM<sub>(2:1)</sub> catalyst was prepared by sol-gel method, in which the ratio of TiO<sub>2</sub> to ARM was 2:1, and the prepared TiO<sub>2</sub>/ARM<sub>(2:1)</sub> catalyst was utilized to activate peroxymonosulfate (PMS) for the degradation of metronidazole (MET). X-ray diffractometry (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) analyses showed that the pore volume, pore diameter, and specific surface area of RM were significantly increased by acidification. Acidified RM provided more loading space for TiO<sub>2</sub>, allowing more TiO<sub>2</sub> to be dispersed on the RM surface and in the pore interstitials. The TiO<sub>2</sub>/ARM<sub>(2:1)</sub> composite could expose more highly reactive components, thereby increasing the catalytic activity of the catalyst. X-ray photoelectron spectroscopy (XPS) and electrochemical analyses demonstrated the excellent activity of TiO<sub>2</sub>/ARM<sub>(2:1)</sub> composite in separating and transferring photoinduced electrons and holes. Approximately, 91.0 % of MET (10 mg/L) was decomposed at 60 min under the optimal reaction conditions of the TiO<sub>2</sub>/ARM<sub>(2:1)</sub> catalyst [TiO<sub>2</sub>/ARM<sub>(2:1)</sub>] = 0.05 g/L, [PMS] = 3 mM, and the pH of 5.9. The results of the quenching experiments indicated that the •O<sub>2</sub><sup>−</sup>, <sup>1</sup>O<sub>2</sub> and h<sup>+</sup> were the main reactive species responsible for the degradation of MET in the TiO<sub>2</sub>/ARM<sub>(2:1)</sub>/PMS/vis system. The possible degradation pathways of MET were proposed through Density-Functional Theory (DFT) calculations and liquid chromatography-mass spectrometry (LC-MS). Results. The prediction results of the Toxicity Evaluation Software Tool (T.E.S.T) suggested that the toxicity of MET was effectively reduced after treatment in the TiO<sub>2</sub>/ARM<sub>(2:1)</sub>/PMS/vis system. After five cycling experiments, TiO<sub>2</sub>/ARM <sub>(2:1)</sub> showed excellent stability. This work provided a new perspective on the modification of industrial waste RM applied in the direction of catalysis.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"157 ","pages":"Article 116299"},"PeriodicalIF":3.8,"publicationDate":"2024-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-20DOI: 10.1016/j.optmat.2024.116283
Jamshina Sanam P.K. , Midhun Shah , P.P. Pradyumnan
Bandgap tuning is a key approach to optimizing materials for advanced technologies, enabling the development of more efficient and specialized devices. In this study, we demonstrate the tunability of the bandgap of CuCrO from 2.38 to 4.37 eV via single cation-doping with Ni and Zn, and multi-cation doping with Ni-Zn and Ni-Zn-Mg. XRD analysis reveals structural changes due to lattice distortions by cationic substitution, while FESEM shows the impact of doping on particle size, surface morphology, and crystallinity. The lamellar structure observed with multi-cation doping in FESEM investigations indicates increased structural disorder and defects, causing tailing above the valence band and below the conduction band, significantly reducing the bandgap. The effect of Zn-Ni doping on the lattice is reversed with Mg insertion due to p-p orbital interactions between Mg-O, replacing the d-p interaction in the Cr3＋-O bond, as confirmed by optical studies. UV–Vis and photoluminescence analyses reveal significant shifts in bandgaps and emission spectra, with Ni doping yielding a bandgap of 3.97 eV, Zn doping 3.16 eV, Zn-Ni doping expanding it to 4.37 eV, and Zn-Ni-Mg doping reducing it to 2.38 eV. The dopants also affect emission characteristics, including band edge and deep-level emissions. This study provides valuable insights into the relationship between cationic doping and material properties, guiding the design of CuCrO-based materials with tailored functionalities.
{"title":"Multi-cation doped CuCrO2 crystallite matrix: Exploring bandgap tunability through Ni-Zn and Ni-Zn-Mg doping for optoelectronic application","authors":"Jamshina Sanam P.K. , Midhun Shah , P.P. Pradyumnan","doi":"10.1016/j.optmat.2024.116283","DOIUrl":"10.1016/j.optmat.2024.116283","url":null,"abstract":"<div><div>Bandgap tuning is a key approach to optimizing materials for advanced technologies, enabling the development of more efficient and specialized devices. In this study, we demonstrate the tunability of the bandgap of CuCrO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> from 2.38 to 4.37 eV via single cation-doping with Ni and Zn, and multi-cation doping with Ni-Zn and Ni-Zn-Mg. XRD analysis reveals structural changes due to lattice distortions by cationic substitution, while FESEM shows the impact of doping on particle size, surface morphology, and crystallinity. The lamellar structure observed with multi-cation doping in FESEM investigations indicates increased structural disorder and defects, causing tailing above the valence band and below the conduction band, significantly reducing the bandgap. The effect of Zn-Ni doping on the lattice is reversed with Mg<span><math><msup><mrow></mrow><mrow><mn>2</mn><mo>+</mo></mrow></msup></math></span> insertion due to p-p orbital interactions between Mg<span><math><msup><mrow></mrow><mrow><mn>2</mn><mo>+</mo></mrow></msup></math></span>-O, replacing the d-p interaction in the Cr<sup>3＋</sup>-O bond, as confirmed by optical studies. UV–Vis and photoluminescence analyses reveal significant shifts in bandgaps and emission spectra, with Ni doping yielding a bandgap of 3.97 eV, Zn doping 3.16 eV, Zn-Ni doping expanding it to 4.37 eV, and Zn-Ni-Mg doping reducing it to 2.38 eV. The dopants also affect emission characteristics, including band edge and deep-level emissions. This study provides valuable insights into the relationship between cationic doping and material properties, guiding the design of CuCrO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>-based materials with tailored functionalities.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"157 ","pages":"Article 116283"},"PeriodicalIF":3.8,"publicationDate":"2024-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-19DOI: 10.1016/j.optmat.2024.116300
Hervin Maulina , Eri Widianto , Emmistasega Subama , Muhammad Riswan , Cipto Driyo , Dwi Nugraheni Rositawati , Fahrudin Nugroho , Moh Edi Wibowo , Iman Santoso
Incorporating graphene into relevant technologies requires its integration with commercially suitable substrates. Understanding the interactions between graphene and these substrates is crucial, as graphene serves as an ideal model system for investigating electronic phenomena. In this work, we report the optical properties of multilayer graphene on nickel substrates using spectroscopic ellipsometry. We provide information on the spectral dependence of optical properties of multilayer graphene, such as the complex dielectric constant, refractive index, and optical conductivity in the energy range of 1.6–5.0 eV. The optical conductivity profile obtained from SE analysis showed a symmetrical peak at 4.38 eV, suggesting an interband transition from the to orbital at the M point. The graphene/Ni interaction generated changes in the number of available states below the Fermi level, leading to significant changes in electron density. Our result provides the information essential for understanding relevant research and developing graphene-based optoelectronic applications.
要将石墨烯应用到相关技术中，就必须将其与商业上适用的基底相结合。了解石墨烯与这些基底之间的相互作用至关重要，因为石墨烯是研究电子现象的理想模型系统。在这项工作中，我们利用光谱椭偏仪报告了镍基底上多层石墨烯的光学特性。我们提供了多层石墨烯光学特性的光谱依赖性信息，如复介电常数、折射率和 1.6-5.0 eV 能量范围内的光导率。通过 SE 分析获得的光导率曲线在 4.38 eV 处显示出一个对称峰，表明在 M 点存在从 π 到 π∗ 轨道的带间跃迁。石墨烯/镍的相互作用导致费米级以下可用态的数量发生变化，从而导致电子密度的显著变化。我们的研究结果为了解相关研究和开发基于石墨烯的光电应用提供了重要信息。
{"title":"Optical properties of CVD-grown multilayer graphene on nickel using spectroscopic ellipsometry","authors":"Hervin Maulina , Eri Widianto , Emmistasega Subama , Muhammad Riswan , Cipto Driyo , Dwi Nugraheni Rositawati , Fahrudin Nugroho , Moh Edi Wibowo , Iman Santoso","doi":"10.1016/j.optmat.2024.116300","DOIUrl":"10.1016/j.optmat.2024.116300","url":null,"abstract":"<div><div>Incorporating graphene into relevant technologies requires its integration with commercially suitable substrates. Understanding the interactions between graphene and these substrates is crucial, as graphene serves as an ideal model system for investigating electronic phenomena. In this work, we report the optical properties of multilayer graphene on nickel substrates using spectroscopic ellipsometry. We provide information on the spectral dependence of optical properties of multilayer graphene, such as the complex dielectric constant, refractive index, and optical conductivity in the energy range of 1.6–5.0 eV. The optical conductivity profile obtained from SE analysis showed a symmetrical peak at 4.38 eV, suggesting an interband transition from the <span><math><mrow><mi>π</mi></mrow></math></span> to <span><math><mrow><msup><mi>π</mi><mo>∗</mo></msup></mrow></math></span> orbital at the <em>M</em> point. The graphene/Ni interaction generated changes in the number of available states below the Fermi level, leading to significant changes in electron density. Our result provides the information essential for understanding relevant research and developing graphene-based optoelectronic applications.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"157 ","pages":"Article 116300"},"PeriodicalIF":3.8,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-19DOI: 10.1016/j.optmat.2024.116301
Dapeng Xu, Zhanpeng Wang, Song Zhang, Wei Yang, Lin Zhou, Jiajia Li, Qiaoqin Guo, Wei Gao, Jian Chen
Surface-Enhanced Raman Scattering (SERS) is a fast-responding and non-destructive ultra-sensitive detection technique that can replace traditional chromatographic and spectroscopic analysis techniques. In this experiment, dendritic copper nanostructures were prepared by the solid-state ionics method and the vacuum hot evaporation process with an applied current of I = 9 μA. Using them as a SERS substrate, Raman detection was performed on the dye molecules Rhodamine 6G (R6G) and Congo Red (CR) to determine SERS enhancement performance. It is found that the growth of the prepared copper nanostructures has a top-end dominant phenomenon. The fractal dimension of the copper nanostructure was calculated using fractal theory, and it was revealed to be 1.560. Scanning electron microscopy (SEM) results showed that a large number of 60–80 nm regularly arranged copper nanoparticles were attached to the surface of the dendritic copper nanostructure. This is beneficial to increase the surface roughness of the substrate and improve the detection level of dye molecules. Subsequently, copper nanostructures can sensitively detect R6G and CR solutions as low as 1 × 10−13 mol/L and 1 × 10−7 mol/L, reaching single-molecule levels. The Raman mapping experiment showed that the mean relative standard deviation (RSD) values of R6G and CR were 12.3 % and 12.9 %, indicating high uniformity and reproducibility of the structure. This structure effectively achieves the fusion of uniformity, repeatability, and sensitivity, and shows broad application prospects in food detection.
{"title":"Dendritic copper nanostructures for ultrasensitive detection of rhodamine 6G and Congo red","authors":"Dapeng Xu, Zhanpeng Wang, Song Zhang, Wei Yang, Lin Zhou, Jiajia Li, Qiaoqin Guo, Wei Gao, Jian Chen","doi":"10.1016/j.optmat.2024.116301","DOIUrl":"10.1016/j.optmat.2024.116301","url":null,"abstract":"<div><div>Surface-Enhanced Raman Scattering (SERS) is a fast-responding and non-destructive ultra-sensitive detection technique that can replace traditional chromatographic and spectroscopic analysis techniques. In this experiment, dendritic copper nanostructures were prepared by the solid-state ionics method and the vacuum hot evaporation process with an applied current of I = 9 μA. Using them as a SERS substrate, Raman detection was performed on the dye molecules Rhodamine 6G (R6G) and Congo Red (CR) to determine SERS enhancement performance. It is found that the growth of the prepared copper nanostructures has a top-end dominant phenomenon. The fractal dimension of the copper nanostructure was calculated using fractal theory, and it was revealed to be 1.560. Scanning electron microscopy (SEM) results showed that a large number of 60–80 nm regularly arranged copper nanoparticles were attached to the surface of the dendritic copper nanostructure. This is beneficial to increase the surface roughness of the substrate and improve the detection level of dye molecules. Subsequently, copper nanostructures can sensitively detect R6G and CR solutions as low as 1 × 10<sup>−13</sup> mol/L and 1 × 10<sup>−7</sup> mol/L, reaching single-molecule levels. The Raman mapping experiment showed that the mean relative standard deviation (RSD) values of R6G and CR were 12.3 % and 12.9 %, indicating high uniformity and reproducibility of the structure. This structure effectively achieves the fusion of uniformity, repeatability, and sensitivity, and shows broad application prospects in food detection.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"157 ","pages":"Article 116301"},"PeriodicalIF":3.8,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Despite a decade of extensive research on two-dimensional transition metal dichalcogenides, there are still some gaps in our understanding of their remarkable properties, limiting their potential applications. One such gap relates to the properties of these alloys, which offer tunable band gaps and can serve as the basis for various optoelectronic and nonlinear optical devices. A comprehensive understanding of the ultrafast charge carrier excitation and relaxation dynamics as well as their characteristic relaxation time constants, is crucial for the further use of these materials in specific applications. In this work, we experimentally investigate the dynamics of ultrafast relaxation processes in monolayer MoS2xSe2(1-x) alloys on a Si/SiO2 substrate using time-resolved spectroscopy. We determine the characteristic relaxation time constants for structures with different stoichiometric compositions and refine these constants by accounting for interference effects arising from the substrate.
{"title":"Quantifying relaxation time constants in MoS2xSe2(1-x) alloys: Impact of Stoichiometry and Si/SiO2 interference","authors":"Nikita Pimenov, Ekaterina Lebedeva, Sergey Lavrov, Andrey Kudryavtsev, Fyodor Zhukov, Elena Mishina","doi":"10.1016/j.optmat.2024.116292","DOIUrl":"10.1016/j.optmat.2024.116292","url":null,"abstract":"<div><div>Despite a decade of extensive research on two-dimensional transition metal dichalcogenides, there are still some gaps in our understanding of their remarkable properties, limiting their potential applications. One such gap relates to the properties of these alloys, which offer tunable band gaps and can serve as the basis for various optoelectronic and nonlinear optical devices. A comprehensive understanding of the ultrafast charge carrier excitation and relaxation dynamics as well as their characteristic relaxation time constants, is crucial for the further use of these materials in specific applications. In this work, we experimentally investigate the dynamics of ultrafast relaxation processes in monolayer MoS<sub>2x</sub>Se<sub>2(1-x)</sub> alloys on a Si/SiO<sub>2</sub> substrate using time-resolved spectroscopy. We determine the characteristic relaxation time constants for structures with different stoichiometric compositions and refine these constants by accounting for interference effects arising from the substrate.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"157 ","pages":"Article 116292"},"PeriodicalIF":3.8,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-18DOI: 10.1016/j.optmat.2024.116295
Xiao-shan Miao , Jia-wei Sun , Fu Ma , Hong-jian Zhao , Yan Zhou , Zheng-bing Han , Xu Li
Zn–SnO2/BiOBr, a novel heterojunction material for photocatalytic dye degradation, was synthesized successfully using the one-step hydrothermal method. The formation of the heterojunction enhanced the vacancy coupling effect. The photocatalytic experiment results showed that the degradation rate of Rhodamine B (RhB) due to 0.3Zn–SnO2/BiOBr (the heterojunction formed when the molar ratio of Zn–SnO2 to BiOBr was 0.3) within 15 min was 9.27 and 476.9 times that of BiOBr and Zn–SnO2, respectively. Additionally, the degradation rate of basic fuchsin (BF) due to 0.3Zn–SnO2/BiOBr was 4.2 and 21.9 times that of BiOBr and Zn–SnO2, respectively. The significantly improved photocatalytic performance was because many oxygen vacancies in Zn–SnO2/BiOBr collaborated with the type-II heterojunction to promote a narrow bandgap value efficiently, increasing the photogenerated electrons (e–) and hole (h+), an increased charge separation efficiency under visible light, and favored the photocatalytic degradation of dyes.
{"title":"Construction of Type-II Zn–SnO2/BiOBr heterojunctions with Dual-oxygen vacancies for enhanced photocatalytic degradation","authors":"Xiao-shan Miao , Jia-wei Sun , Fu Ma , Hong-jian Zhao , Yan Zhou , Zheng-bing Han , Xu Li","doi":"10.1016/j.optmat.2024.116295","DOIUrl":"10.1016/j.optmat.2024.116295","url":null,"abstract":"<div><div>Zn–SnO<sub>2</sub>/BiOBr, a novel heterojunction material for photocatalytic dye degradation, was synthesized successfully using the one-step hydrothermal method. The formation of the heterojunction enhanced the vacancy coupling effect. The photocatalytic experiment results showed that the degradation rate of Rhodamine B (RhB) due to 0.3Zn–SnO<sub>2</sub>/BiOBr (the heterojunction formed when the molar ratio of Zn–SnO<sub>2</sub> to BiOBr was 0.3) within 15 min was 9.27 and 476.9 times that of BiOBr and Zn–SnO<sub>2</sub>, respectively. Additionally, the degradation rate of basic fuchsin (BF) due to 0.3Zn–SnO<sub>2</sub>/BiOBr was 4.2 and 21.9 times that of BiOBr and Zn–SnO<sub>2</sub>, respectively. The significantly improved photocatalytic performance was because many oxygen vacancies in Zn–SnO<sub>2</sub>/BiOBr collaborated with the type-II heterojunction to promote a narrow bandgap value efficiently, increasing the photogenerated electrons (e<sup>–</sup>) and hole (h<sup>+</sup>), an increased charge separation efficiency under visible light, and favored the photocatalytic degradation of dyes.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"157 ","pages":"Article 116295"},"PeriodicalIF":3.8,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-10-18DOI: 10.1016/j.optmat.2024.116290
L. Kotsedi , A. Abdelmalek , V. Bharadwaj , C.B. Mtshali , Z.Y. Nuru , B. Sotillo , G. Coccia , S.M. Eaton , R. Ramponi , E.H. Amara , M. Maaza
The study of the relaxation mechanism of amorphous germanium after femtosecond laser irradiation is presented in this work. In particular, a thin germanium coating was deposited onto a glass substrate through the electron beam vacuum coating method. The substrate was kept at room temperature during the coating process, which resulted in a deposited layer characterized by an amorphous microstructure, as observed from the X-ray diffraction. The germanium layer was then irradiated with a femtosecond laser at 1030 nm wavelength, while varying the net fluence from 15 J cm−2 to 90 J cm−2. Moreover, an extended two temperature model was used to extract the electronic and lattice temperature of the laser heated germanium coating, showing a 32 % contribution from heating due to the thermal accumulation effect. The microstructural and morphological studies of the irradiated samples were carried out using θ-2θ X-ray diffraction and high-resolution scanning electron microscopy. From the X-ray diffraction results, it was observed that at higher laser fluence there is an emergence of crystallinity on the germanium layer, with no evidence of oxidation. On the surface, the morphology was observed to evolve to granular sphere, attributed to melting of the material. Finally, an increase in absorbance with laser fluence was observed and the optical band gap of the coating was calculated.
本研究介绍了飞秒激光辐照后非晶锗的弛豫机制。其中，通过电子束真空镀膜法在玻璃基底上沉积了一层薄薄的锗涂层。在镀膜过程中，基片保持在室温下，根据 X 射线衍射的观察结果，沉积层的微观结构为非晶态。然后用波长为 1030 nm 的飞秒激光照射锗层，同时改变 15 J cm-2 至 90 J cm-2 的净通量。此外，还使用扩展的双温模型来提取激光加热锗涂层的电子温度和晶格温度，结果显示热累积效应导致的加热占 32%。利用 θ-2θ X 射线衍射和高分辨率扫描电子显微镜对辐照样品进行了微观结构和形态研究。从 X 射线衍射结果可以看出，在较高的激光能量下，锗层出现结晶，没有氧化迹象。在表面，观察到的形态演变为颗粒状球体，这归因于材料的熔化。最后，观察到吸光度随激光能量的增加而增加，并计算出涂层的光带隙。
{"title":"Optical and microstructural studies of femtosecond laser treated amorphous germanium thin coatings","authors":"L. Kotsedi , A. Abdelmalek , V. Bharadwaj , C.B. Mtshali , Z.Y. Nuru , B. Sotillo , G. Coccia , S.M. Eaton , R. Ramponi , E.H. Amara , M. Maaza","doi":"10.1016/j.optmat.2024.116290","DOIUrl":"10.1016/j.optmat.2024.116290","url":null,"abstract":"<div><div>The study of the relaxation mechanism of amorphous germanium after femtosecond laser irradiation is presented in this work. In particular, a thin germanium coating was deposited onto a glass substrate through the electron beam vacuum coating method. The substrate was kept at room temperature during the coating process, which resulted in a deposited layer characterized by an amorphous microstructure, as observed from the X-ray diffraction. The germanium layer was then irradiated with a femtosecond laser at 1030 nm wavelength, while varying the net fluence from 15 J cm<sup>−2</sup> to 90 J cm<sup>−2</sup>. Moreover, an extended two temperature model was used to extract the electronic and lattice temperature of the laser heated germanium coating, showing a 32 % contribution from heating due to the thermal accumulation effect. The microstructural and morphological studies of the irradiated samples were carried out using θ-2θ X-ray diffraction and high-resolution scanning electron microscopy. From the X-ray diffraction results, it was observed that at higher laser fluence there is an emergence of crystallinity on the germanium layer, with no evidence of oxidation. On the surface, the morphology was observed to evolve to granular sphere, attributed to melting of the material. Finally, an increase in absorbance with laser fluence was observed and the optical band gap of the coating was calculated.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"157 ","pages":"Article 116290"},"PeriodicalIF":3.8,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-18DOI: 10.1016/j.optmat.2024.116296
Thanh Phuong Nguyen , Huu Phuc Dang , Long Giang Nguyen , Cong Danh Le
Luminescent ZnO nano pigments with a hexagonal structure were successfully synthesized using the hydrothermal method. The color fluorescent emission of ink can be tuned by hydrothermal conditions in the synthesis of pigment or by adjusting the pH values of the ink formulation. The ink formula based on luminescent ZnO nano pigments with a concentration of 15 % (w/w) was dispersed and homogenized in the vehicle, including water, PVA, and ethylene glycol. The stable ZnO nano ink formula has the zeta potential value of ξ = −24.8 mV at pH = 7.2, and ZnO pigments have an average particle size of about 500 nm in length and 90 nm in width. The logo samples printed on graphic paper and Couche paper with luminescent ink using a screen printing method show a bright yellow fluorescence at 565 nm under UV irradiation 365 nm and are invisible under normal light. The QR code on paper is readable by a smartphone under UV light. The ZnO nano ink is suitable for information encryption and anti-counterfeiting applications.
{"title":"Synthesis of ZnO nanoparticles-based fluorescent ink for information encryption and security applications","authors":"Thanh Phuong Nguyen , Huu Phuc Dang , Long Giang Nguyen , Cong Danh Le","doi":"10.1016/j.optmat.2024.116296","DOIUrl":"10.1016/j.optmat.2024.116296","url":null,"abstract":"<div><div>Luminescent ZnO nano pigments with a hexagonal structure were successfully synthesized using the hydrothermal method. The color fluorescent emission of ink can be tuned by hydrothermal conditions in the synthesis of pigment or by adjusting the pH values of the ink formulation. The ink formula based on luminescent ZnO nano pigments with a concentration of 15 % (w/w) was dispersed and homogenized in the vehicle, including water, PVA, and ethylene glycol. The stable ZnO nano ink formula has the zeta potential value of ξ = −24.8 mV at pH = 7.2, and ZnO pigments have an average particle size of about 500 nm in length and 90 nm in width. The logo samples printed on graphic paper and Couche paper with luminescent ink using a screen printing method show a bright yellow fluorescence at 565 nm under UV irradiation 365 nm and are invisible under normal light. The QR code on paper is readable by a smartphone under UV light. The ZnO nano ink is suitable for information encryption and anti-counterfeiting applications.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"157 ","pages":"Article 116296"},"PeriodicalIF":3.8,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号