Pub Date : 2025-03-27DOI: 10.1016/j.cap.2025.03.013
Thi-Hien Pham , Van Thanh Hoang , Lemma Teshome Tufa , Jaebeom Lee , Doan Van Huong , Van Tan Tran , Van-Tuan Hoang , Anh-Tuan Le
Superparamagnetic nanoparticles (NPs) have gained significant attention for their unique properties and applications, but facile and scalable synthesis combining their superparamagnetic traits with the stability of larger particles remains challenging. This study presents a novel one-pot solvothermal method for synthesizing size-tunable Fe3O4 microclusters that preserve superparamagnetic properties at the microscale. We systematically investigated the effects of reaction time and surfactant type on the formation and characteristics of these microclusters, achieving precise size control ranging from 0.37 to 1.8 μm. Through detailed analysis of intermediate products and final structures, we elucidated the growth mechanism, revealing a clear clustering process of primary nanocrystals into larger spherical microclusters. This study introduces a versatile and novel approach to controlling the properties of Fe3O4 microclusters, bridging the gap between nanoscale and microscale superparamagnetic materials. This research not only offers a versatile approach to tailoring Fe3O4 microcluster properties for specific applications but also contributes to the broader understanding of size-controlled synthesis of magnetic materials.
{"title":"One-pot synthesis of size-controlled Fe3O4 microclusters: Preserving superparamagnetism at microscale","authors":"Thi-Hien Pham , Van Thanh Hoang , Lemma Teshome Tufa , Jaebeom Lee , Doan Van Huong , Van Tan Tran , Van-Tuan Hoang , Anh-Tuan Le","doi":"10.1016/j.cap.2025.03.013","DOIUrl":"10.1016/j.cap.2025.03.013","url":null,"abstract":"<div><div>Superparamagnetic nanoparticles (NPs) have gained significant attention for their unique properties and applications, but facile and scalable synthesis combining their superparamagnetic traits with the stability of larger particles remains challenging. This study presents a novel one-pot solvothermal method for synthesizing size-tunable Fe<sub>3</sub>O<sub>4</sub> microclusters that preserve superparamagnetic properties at the microscale. We systematically investigated the effects of reaction time and surfactant type on the formation and characteristics of these microclusters, achieving precise size control ranging from 0.37 to 1.8 μm. Through detailed analysis of intermediate products and final structures, we elucidated the growth mechanism, revealing a clear clustering process of primary nanocrystals into larger spherical microclusters. This study introduces a versatile and novel approach to controlling the properties of Fe<sub>3</sub>O<sub>4</sub> microclusters, bridging the gap between nanoscale and microscale superparamagnetic materials. This research not only offers a versatile approach to tailoring Fe<sub>3</sub>O<sub>4</sub> microcluster properties for specific applications but also contributes to the broader understanding of size-controlled synthesis of magnetic materials.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"74 ","pages":"Pages 25-33"},"PeriodicalIF":2.4,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143747252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-24DOI: 10.1016/j.cap.2025.03.008
Vinuta , H.C. Manjunatha , Y.S. Vidya , S. Manjunatha , R. Munirathnam , M. Shivanna , Suman Kumar , K.N. Sridhar
Zn2V2O7:Ce Nanoparticles (NPs) (ZV:Ce), are produced by a solution combustion process mediated by an extract from leaves. The diffraction pattern shows alignment with the ZV host matrix. The crystals grown with monoclinic crystal structure and space group. Furthermore, as the dopant concentration changes, a shift in the diffraction pattern was noticed. Scherrer's approach yielded a crystallite size that nearly matched the results of transmission electron microscopy research. The surface morphology changes from irregularly shaped NPs to hexagonal ones. Furthermore, a modulation of Eg is shown by Tauc's plot analysis of the UV-visible absorption spectra, which shifts from 2.98 to 2.87 eV with increasing dopant quantity. The PL emission spectra at 310 nm consist of peaks located at 417, 457, 482 and 526 nm. The emission peaks at 417, 457 and 482 nm belong to the 5D3/2 → 2F7/2 transition and 526 nm can be attributed to the 5D3/2 → 2F7/2 transition of Ce3+ within the host matrix. The CIE coordinates fall in the light blue emission region. The average CCT of 9078 K shows a cooler appearance. From all these results, the present nano phosphor materials might be a promising candidate in blue LEDs and in display technology. The materials showing a cooler appearance find applications in museums, galleries, offices, outdoor lighting, etc. Electrochemical studies revealed that super capacitance values ranged from 94.67 to 158.12 F/g at a scan rate of 10 mV/s, with increasing Ce3+ quantity in Zn2V2O7 nanoparticles.
{"title":"Photoluminescence and electrochemical studies of Ce3+-doped Zn2V2O7 nanoparticles synthesized via green route","authors":"Vinuta , H.C. Manjunatha , Y.S. Vidya , S. Manjunatha , R. Munirathnam , M. Shivanna , Suman Kumar , K.N. Sridhar","doi":"10.1016/j.cap.2025.03.008","DOIUrl":"10.1016/j.cap.2025.03.008","url":null,"abstract":"<div><div>Zn<sub>2</sub>V<sub>2</sub>O<sub>7</sub>:Ce Nanoparticles (NPs) (ZV:Ce), are produced by a solution combustion process mediated by an extract from <span><math><mi>M</mi><mi>e</mi><mi>n</mi><mi>t</mi><mi>h</mi><mi>a</mi><mi>s</mi><mi>p</mi><mi>i</mi><mi>c</mi><mi>a</mi><mi>t</mi><mi>a</mi></math></span> leaves. The diffraction pattern shows alignment with the ZV host matrix. The crystals grown with monoclinic crystal structure and <span><math><mi>C</mi><mn>2</mn><mo>/</mo><mi>c</mi><mo>(</mo><mn>2</mn><mo>/</mo><mi>m</mi><mo>)</mo></math></span> space group. Furthermore, as the dopant concentration changes, a shift in the diffraction pattern was noticed. Scherrer's approach yielded a crystallite size that nearly matched the results of transmission electron microscopy research. The surface morphology changes from irregularly shaped NPs to hexagonal ones. Furthermore, a modulation of E<sub><em>g</em></sub> is shown by Tauc's plot analysis of the UV-visible absorption spectra, which shifts from 2.98 to 2.87 eV with increasing dopant quantity. The PL emission spectra at 310 nm consist of peaks located at 417, 457, 482 and 526 nm. The emission peaks at 417, 457 and 482 nm belong to the 5D<sub>3/2</sub> → <sup>2</sup>F<sub>7/2</sub> transition and 526 nm can be attributed to the 5D<sub>3/2</sub> → <sup>2</sup>F<sub>7/2</sub> transition of Ce<sup>3+</sup> within the host matrix. The CIE coordinates fall in the light blue emission region. The average CCT of 9078 K shows a cooler appearance. From all these results, the present nano phosphor materials might be a promising candidate in blue LEDs and in display technology. The materials showing a cooler appearance find applications in museums, galleries, offices, outdoor lighting, etc. Electrochemical studies revealed that super capacitance values ranged from 94.67 to 158.12 F/g at a scan rate of 10 mV/s, with increasing Ce<sup>3+</sup> quantity in Zn<sub>2</sub>V<sub>2</sub>O<sub>7</sub> nanoparticles.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"74 ","pages":"Pages 1-11"},"PeriodicalIF":2.4,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143696858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-19DOI: 10.1016/j.cap.2025.03.009
Noor ul Ain , Saqlain Yousuf , Zi-Yu Cao , Anir S. Sharbirin , Afrizal L. Fadli , Jeongyong Kim , Yongmin Kim , Hanoh Lee , Tuson Park
Recent observation of superconductivity in La3Ni2O7-δ have sparked renewed interest in high-temperature superconductors. Despite years of research, challenges with existing samples have raised questions about their intrinsic features, demanding on exploring new synthesis routes on this material. In this study, single crystals of La3Ni2O7-δ were grown using CsCl flux for the first time, while polycrystalline synthesis was explored through solid-state reaction. The electrical resistivity of the polycrystalline samples showed an insulating behavior, whereas the single crystals exhibited metallic behavior with an anomaly at T∗ ∼110 K, likely due to a density wave order. A distinct V-shaped magnetoresistance is observed at temperatures below T∗ in a single crystal sample. Furthermore, Raman spectroscopy of the single crystals highlights prominent phonon modes, reflecting the complex bilayer structure of La3Ni2O7-δ. These findings emphasized a new synthesis route for La3Ni2O7-δ and highlight the influence of synthesis conditions on its magnetic and electronic properties.
{"title":"Synthesis and characterization of single crystal and polycrystalline La3Ni2O7-δ","authors":"Noor ul Ain , Saqlain Yousuf , Zi-Yu Cao , Anir S. Sharbirin , Afrizal L. Fadli , Jeongyong Kim , Yongmin Kim , Hanoh Lee , Tuson Park","doi":"10.1016/j.cap.2025.03.009","DOIUrl":"10.1016/j.cap.2025.03.009","url":null,"abstract":"<div><div>Recent observation of superconductivity in La<sub>3</sub>Ni<sub>2</sub>O<sub>7-<em>δ</em></sub> have sparked renewed interest in high-temperature superconductors. Despite years of research, challenges with existing samples have raised questions about their intrinsic features, demanding on exploring new synthesis routes on this material. In this study, single crystals of La<sub>3</sub>Ni<sub>2</sub>O<sub>7-<em>δ</em></sub> were grown using CsCl flux for the first time, while polycrystalline synthesis was explored through solid-state reaction. The electrical resistivity of the polycrystalline samples showed an insulating behavior, whereas the single crystals exhibited metallic behavior with an anomaly at <em>T</em>∗ ∼110 K, likely due to a density wave order. A distinct V-shaped magnetoresistance is observed at temperatures below <em>T</em>∗ in a single crystal sample. Furthermore, Raman spectroscopy of the single crystals highlights prominent phonon modes, reflecting the complex bilayer structure of La<sub>3</sub>Ni<sub>2</sub>O<sub>7-<em>δ</em></sub>. These findings emphasized a new synthesis route for La<sub>3</sub>Ni<sub>2</sub>O<sub>7-<em>δ</em></sub> and highlight the influence of synthesis conditions on its magnetic and electronic properties.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"74 ","pages":"Pages 19-24"},"PeriodicalIF":2.4,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143735115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-18DOI: 10.1016/j.cap.2025.03.010
Junho Yun, Dongchul Sung, Yunjae Kim, Suklyun Hong
A notable feature of 2D materials is their ability to form van der Waals heterostructures, enabling tailored electronic properties. Among these, Janus TMDs, with their asymmetric structure and dipole moment, exhibit unique properties like piezoelectricity, Rashba effect, and catalytic activity. In this study, we have performed density functional theory (DFT) calculations to investigate the electronic properties of a heterostructure composed of bilayer graphene (BLG) and a Janus MoSTe monolayer, focusing on the difference in interfacial contact behaviors between them. Our calculations indicate that the Dirac cone in BLG within the BLG/Janus MoSTe heterostructure opens due to electron transfer at the metal-semiconductor interface and the electric field generated by the asymmetry of Janus MoSTe. Depending on the contact orientation, this interaction results in BLG's bandgaps of 46 meV and 70 meV, respectively, highlighting the tunability and potential applications of BLG/Janus TMD heterostructures in optoelectronic devices.
{"title":"Electronic properties of bilayer graphene/Janus MoSTe heterostructure","authors":"Junho Yun, Dongchul Sung, Yunjae Kim, Suklyun Hong","doi":"10.1016/j.cap.2025.03.010","DOIUrl":"10.1016/j.cap.2025.03.010","url":null,"abstract":"<div><div>A notable feature of 2D materials is their ability to form van der Waals heterostructures, enabling tailored electronic properties. Among these, Janus TMDs, with their asymmetric structure and dipole moment, exhibit unique properties like piezoelectricity, Rashba effect, and catalytic activity. In this study, we have performed density functional theory (DFT) calculations to investigate the electronic properties of a heterostructure composed of bilayer graphene (BLG) and a Janus MoSTe monolayer, focusing on the difference in interfacial contact behaviors between them. Our calculations indicate that the Dirac cone in BLG within the BLG/Janus MoSTe heterostructure opens due to electron transfer at the metal-semiconductor interface and the electric field generated by the asymmetry of Janus MoSTe. Depending on the contact orientation, this interaction results in BLG's bandgaps of 46 meV and 70 meV, respectively, highlighting the tunability and potential applications of BLG/Janus TMD heterostructures in optoelectronic devices.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"74 ","pages":"Pages 12-18"},"PeriodicalIF":2.4,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143714479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-15DOI: 10.1016/j.cap.2025.03.007
Raji S, K. Prabhakaran
A process for preparing thermally insulating carbon composite panels (CCP) from used cotton cloth is reported. The pliable cotton cloth is transformed into rigid carbon grid sheets by carbonization after impregnation with a sucrose solution. The layered carbon composite panels are obtained by hand layup of phenol-formaldehyde (PF) polymer solution-impregnated carbon grid sheet followed by curing and carbonization. The carbon composite panels exhibit grid-like pores in the X-Y plane and lamellar-type pores in the lateral plane. Due to their layered structure, the carbon composite panels exhibit pseudo-plastic failure under flexural mode. The density, compressive strength, and flexural strength are modulated in the ranges of 0.45 ± 0.0004 to 0.57 ± 0.0068 g cm−3, 0.86 ± 0.04 to 2.03 ± 0.10 MPa, and 2.6 ± 0.11 to 4.5 ± 0.16 MPa, respectively, by varying the PF solution concentrations from 60 to 100 vol%. The carbon composite panels exhibit oxidation resistance up to 470 °C, excellent fire resistance, and low thermal conductivity in the 0.187 ± 0.0004 to 0.273 ± 0.0014 W m−1. K−1 range. The high EMI shielding effectiveness in the range of 40–67 dB exhibited by the carbon composite panels of 5 mm thickness is due to the conductive and dielectric losses and multiple internal reflections within the grid-like and lamellar-type pores.
{"title":"Fire-resistant layered carbon composite panels from used cotton cloth for thermal insulation and EMI shielding applications","authors":"Raji S, K. Prabhakaran","doi":"10.1016/j.cap.2025.03.007","DOIUrl":"10.1016/j.cap.2025.03.007","url":null,"abstract":"<div><div>A process for preparing thermally insulating carbon composite panels (CCP) from used cotton cloth is reported. The pliable cotton cloth is transformed into rigid carbon grid sheets by carbonization after impregnation with a sucrose solution. The layered carbon composite panels are obtained by hand layup of phenol-formaldehyde (PF) polymer solution-impregnated carbon grid sheet followed by curing and carbonization. The carbon composite panels exhibit grid-like pores in the X-Y plane and lamellar-type pores in the lateral plane. Due to their layered structure, the carbon composite panels exhibit pseudo-plastic failure under flexural mode. The density, compressive strength, and flexural strength are modulated in the ranges of 0.45 ± 0.0004 to 0.57 ± 0.0068 g cm<sup>−3</sup>, 0.86 ± 0.04 to 2.03 ± 0.10 MPa, and 2.6 ± 0.11 to 4.5 ± 0.16 MPa, respectively, by varying the PF solution concentrations from 60 to 100 vol%. The carbon composite panels exhibit oxidation resistance up to 470 °C, excellent fire resistance, and low thermal conductivity in the 0.187 ± 0.0004 to 0.273 ± 0.0014 W m<sup>−1</sup>. K<sup>−1</sup> range. The high EMI shielding effectiveness in the range of 40–67 dB exhibited by the carbon composite panels of 5 mm thickness is due to the conductive and dielectric losses and multiple internal reflections within the grid-like and lamellar-type pores.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"73 ","pages":"Pages 117-126"},"PeriodicalIF":2.4,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-12DOI: 10.1016/j.cap.2025.03.006
Twinkle Khanna , Subhrajit Konwar , Saloni Saloni , S.N.F. Yusuf , Pramod K. Singh , Geeta Durga
Perylene diimides (PDIs) have emerged as an excellent n-type semiconductor substitute for fullerenes in energy devices. A novel PDI, N, N′-bis-(2-phenylethyl)-3,4,9,10-perylene bis(dicarboximide)(PDEA), was synthesized and its structure was thoroughly characterized using Fourier transforms infrared spectroscopy (FTIR), High-resolution mass spectroscopy (HRMS), Proton Nuclear magnetic resonance (1H NMR). The optical properties of the PDI were evaluated using UV–visible, and Photoluminescence (PL) spectroscopic techniques. The UV–Visible spectrum of PDEA exhibited a broad absorption band in the visible range (400–800 nm), with yellowish-green fluorescence emission under a UV lamp. The structure of PDEA was optimized using Density Functional Theory (DFT) with the B3LYP/6-31G (d, p) basis set, and its optoelectronic properties were evaluated in a variety of solvents of different polarities. Further, Cyclic Voltammetry (CV) was utilized to examine the electrochemical redox behaviour of PDEA in acetonitrile which was observed to be one-electron quasi-reversible. The as-synthesized PDEA was used to fabricate the DSSC and was found to exhibit a good photovoltaic performance with a fill factor (FF) of 72, an open-circuit voltage (Voc) of 0.52 V, a PCE (power conversion efficiency) of 0.63 %, and a Jsc (short circuit current density) of 1.67 mA/cm2. The above-mentioned characteristics of the PDEA may have applications in photovoltaics, fluorescence-based detectors, n-channel field-effect transistors, and other related areas.
{"title":"Structural and optoelectronic analysis of a novel perylene diimide as a light-harvesting material for dye-sensitized solar cells","authors":"Twinkle Khanna , Subhrajit Konwar , Saloni Saloni , S.N.F. Yusuf , Pramod K. Singh , Geeta Durga","doi":"10.1016/j.cap.2025.03.006","DOIUrl":"10.1016/j.cap.2025.03.006","url":null,"abstract":"<div><div>Perylene diimides (PDIs) have emerged as an excellent n-type semiconductor substitute for fullerenes in energy devices. A novel PDI, N, N′-bis-(2-phenylethyl)-3,4,9,10-perylene bis(dicarboximide)(PDEA), was synthesized and its structure was thoroughly characterized using Fourier transforms infrared spectroscopy (FTIR), High-resolution mass spectroscopy (HRMS), Proton Nuclear magnetic resonance (<sup>1</sup>H NMR). The optical properties of the PDI were evaluated using UV–visible, and Photoluminescence (PL) spectroscopic techniques. The UV–Visible spectrum of PDEA exhibited a broad absorption band in the visible range (400–800 nm), with yellowish-green fluorescence emission under a UV lamp. The structure of PDEA was optimized using Density Functional Theory (DFT) with the B3LYP/6-31G (d, p) basis set, and its optoelectronic properties were evaluated in a variety of solvents of different polarities. Further, Cyclic Voltammetry (CV) was utilized to examine the electrochemical redox behaviour of PDEA in acetonitrile which was observed to be one-electron quasi-reversible. The as-synthesized PDEA was used to fabricate the DSSC and was found to exhibit a good photovoltaic performance with a fill factor (FF) of 72, an open-circuit voltage (V<sub>oc</sub>) of 0.52 V, a PCE (power conversion efficiency) of 0.63 %, and a Jsc (short circuit current density) of 1.67 mA/cm<sup>2</sup>. The above-mentioned characteristics of the PDEA may have applications in photovoltaics, fluorescence-based detectors, n-channel field-effect transistors, and other related areas.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"73 ","pages":"Pages 127-135"},"PeriodicalIF":2.4,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143680654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-12DOI: 10.1016/j.cap.2025.03.005
Xiangyuan Duan, Shuyan Xu
Fluorescent composite films were prepared using polyvinyl alcohol (PVA) as the substrate and NaYF4:Eu3+ phosphors and κ-carrageenan powder (KC) as the fillers by the casting method. The impact of incorporating NaYF4:Eu3+ on the structural, morphological, mechanical property, thermal stability, and optical characteristics of PVA/KC films was examined. The incorporation of KC promoted the formation of hydrogen bonds between KC and PVA. Consequently, the water contact angle of the films increased by approximately 10°, indicating improved water resistance. Meanwhile, the incorporation of NaYF4:Eu3+ increased the thermal stability of the films, with the temperature at 5 % mass loss rising by approximately 13 °C. Additionally, the mass retention at 600 °C improved by 3.47 %. Notably, the addition of NaYF4:Eu3+ had a negligible effect on the transparency of the films while imparting fluorescent properties. Under UV excitation at 395 nm, the films exhibited maximum fluorescence intensity at 616 nm, indicating a significant fluorescence effect.
{"title":"Synthesis and characterization of PVA/KC/NaYF4:Eu3+ composite fluorescent films","authors":"Xiangyuan Duan, Shuyan Xu","doi":"10.1016/j.cap.2025.03.005","DOIUrl":"10.1016/j.cap.2025.03.005","url":null,"abstract":"<div><div>Fluorescent composite films were prepared using polyvinyl alcohol (PVA) as the substrate and NaYF<sub>4</sub>:Eu<sup>3+</sup> phosphors and κ-carrageenan powder (KC) as the fillers by the casting method. The impact of incorporating NaYF<sub>4</sub>:Eu<sup>3+</sup> on the structural, morphological, mechanical property, thermal stability, and optical characteristics of PVA/KC films was examined. The incorporation of KC promoted the formation of hydrogen bonds between KC and PVA. Consequently, the water contact angle of the films increased by approximately 10°, indicating improved water resistance. Meanwhile, the incorporation of NaYF<sub>4</sub>:Eu<sup>3+</sup> increased the thermal stability of the films, with the temperature at 5 % mass loss rising by approximately 13 °C. Additionally, the mass retention at 600 °C improved by 3.47 %. Notably, the addition of NaYF<sub>4</sub>:Eu<sup>3+</sup> had a negligible effect on the transparency of the films while imparting fluorescent properties. Under UV excitation at 395 nm, the films exhibited maximum fluorescence intensity at 616 nm, indicating a significant fluorescence effect.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"73 ","pages":"Pages 136-144"},"PeriodicalIF":2.4,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143680655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-09DOI: 10.1016/j.cap.2025.03.001
Shengyi Liu , Shang Gao , Duan Gao , Li Wang , Wenbin Song , Han Yin , Ying Zhu , Jingjing Zhang , Qianmiao Yu , Xin Chen
Successfully synthesized LaCaGaO4: Er3+ and LaCaGaO4: Er3+/Yb3+ phosphors via high-temperature solid-state reactions and thoroughly investigated their up-conversion luminescence properties under 980 nm and 1550 nm excitation. X-ray diffraction analysis confirmed the phase purity of the materials, and up-conversion luminescence measurements demonstrated emissions in the visible and near-infrared regions, primarily at 530 nm, 550 nm, 670 nm, and 810 nm, corresponding to Er3+ transitions. Mechanistic studies revealed that under 980 nm excitation, both green and red emissions are two-photon processes, while under 1550 nm excitation, these emissions are driven by three-photon processes. Co-doping with Yb3+ enhanced luminescence intensity, with an increase in the red-to-green emission ratio as the Yb3+ concentration increased. Furthermore, these materials exhibited excellent temperature sensing capabilities, with fluorescence intensity ratios from thermally coupled energy levels showing good agreement with the Boltzmann distribution. Maximum sensitivities SAMAX of 0.00054 K-1 (980 nm excitation) and 0.00632 K-1 (1550 nm excitation) were achieved, highlighting their potential for applications in optical thermometry, color tuning, and anti-counterfeiting.
{"title":"Up-conversion phosphor LaCaGaO4: Er3+/Yb3+ for the optical temperature sensing and anti-counterfeiting","authors":"Shengyi Liu , Shang Gao , Duan Gao , Li Wang , Wenbin Song , Han Yin , Ying Zhu , Jingjing Zhang , Qianmiao Yu , Xin Chen","doi":"10.1016/j.cap.2025.03.001","DOIUrl":"10.1016/j.cap.2025.03.001","url":null,"abstract":"<div><div>Successfully synthesized LaCaGaO<sub>4</sub>: Er<sup>3+</sup> and LaCaGaO<sub>4</sub>: Er<sup>3+</sup>/Yb<sup>3+</sup> phosphors via high-temperature solid-state reactions and thoroughly investigated their up-conversion luminescence properties under 980 nm and 1550 nm excitation. X-ray diffraction analysis confirmed the phase purity of the materials, and up-conversion luminescence measurements demonstrated emissions in the visible and near-infrared regions, primarily at 530 nm, 550 nm, 670 nm, and 810 nm, corresponding to Er<sup>3+</sup> transitions. Mechanistic studies revealed that under 980 nm excitation, both green and red emissions are two-photon processes, while under 1550 nm excitation, these emissions are driven by three-photon processes. Co-doping with Yb<sup>3+</sup> enhanced luminescence intensity, with an increase in the red-to-green emission ratio as the Yb<sup>3+</sup> concentration increased. Furthermore, these materials exhibited excellent temperature sensing capabilities, with fluorescence intensity ratios from thermally coupled energy levels showing good agreement with the Boltzmann distribution. Maximum sensitivities S<sub>A</sub><sup>MAX</sup> of 0.00054 K<sup>-1</sup> (980 nm excitation) and 0.00632 K<sup>-1</sup> (1550 nm excitation) were achieved, highlighting their potential for applications in optical thermometry, color tuning, and anti-counterfeiting.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"73 ","pages":"Pages 84-97"},"PeriodicalIF":2.4,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143610322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-09DOI: 10.1016/j.cap.2025.03.003
Younsik Kim , Suk Bum Chung , Changyoung Kim
In this work, we discuss a pedagogical method in deriving the expressions for anomalous position and velocity. While we follow the steps used in optics in the derivation of the group velocity, we use Bloch wave functions instead of plane wave states. In comparison to the plane wave case, application of Bloch wave functions results in two additional terms in the expression of the group velocity: the Berry phase factor and anomalous position contributions. These two new terms with distinct origins eventually lead to the known anomalous velocity. Aiming for an intuitive understanding, we simulate the situation under an electric field using linear-combination-of-atomic-orbital states and visually demonstrate that the envelope function exhibits the transverse motion expected from an anomalous velocity.
{"title":"Pedagogical approach to anomalous position and velocity","authors":"Younsik Kim , Suk Bum Chung , Changyoung Kim","doi":"10.1016/j.cap.2025.03.003","DOIUrl":"10.1016/j.cap.2025.03.003","url":null,"abstract":"<div><div>In this work, we discuss a pedagogical method in deriving the expressions for anomalous position and velocity. While we follow the steps used in optics in the derivation of the group velocity, we use Bloch wave functions instead of plane wave states. In comparison to the plane wave case, application of Bloch wave functions results in two additional terms in the expression of the group velocity: the Berry phase factor and anomalous position contributions. These two new terms with distinct origins eventually lead to the known anomalous velocity. Aiming for an intuitive understanding, we simulate the situation under an electric field using linear-combination-of-atomic-orbital states and visually demonstrate that the envelope function exhibits the transverse motion expected from an anomalous velocity.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"73 ","pages":"Pages 112-116"},"PeriodicalIF":2.4,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143629562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-06DOI: 10.1016/j.cap.2025.03.004
Sachin Sharma Ashok Kumar , K. Ramesh , S. Ramesh
Graphene and its derivatives, such as graphene oxide (GO) are new materials with unique properties which have been widely employed as a reinforcing filler material in organic coatings. The superior properties of GO, such as its large surface area, surface wettability, stability, chemical resistance, and high mechanical strength, have resulted the GO material to be a promising additive in anti-corrosion coatings. On the other hand, due to the presence of oxygen-containing functional groups, the GO has exhibited high water dispersibility. In addition, the chemical functionalization that is facilitated by these functional groups on the GO surface resulted in the enhancement of dispersibility and corrosion protection performance. Hence, the GO-based polymer coatings have attracted significant attention globally especially in the corrosion industry. Although, the electrochemical characteristics of GO-polymer nanocomposite coatings have not been explored much. Therefore, in this study, a series of coatings were developed by incorporating various amounts of GO nanoparticles into the polymer matrix. These coatings were then coated on the steel substrates and the barrier protection performance of GO-based coatings was investigated using electrochemical impedance spectroscopy (EIS). In addition, the electrochemical activity was observed by determining the breakpoint frequencies () over a period of 90 days. The results revealed that the incorporation of GO nanoparticles significantly enhanced the corrosion protection performance of the coatings. The results demonstrated that the best corrosion resistance was achieved by the 0.5 % GO coating sample. Fourier transform infrared (FTIR) spectroscopy was employed to verify the chemical structure of the composite coatings.
{"title":"Enhancement of barrier protection of organic coatings with the incorporation of graphene oxide as a reinforcing filler","authors":"Sachin Sharma Ashok Kumar , K. Ramesh , S. Ramesh","doi":"10.1016/j.cap.2025.03.004","DOIUrl":"10.1016/j.cap.2025.03.004","url":null,"abstract":"<div><div>Graphene and its derivatives, such as graphene oxide (GO) are new materials with unique properties which have been widely employed as a reinforcing filler material in organic coatings. The superior properties of GO, such as its large surface area, surface wettability, stability, chemical resistance, and high mechanical strength, have resulted the GO material to be a promising additive in anti-corrosion coatings. On the other hand, due to the presence of oxygen-containing functional groups, the GO has exhibited high water dispersibility. In addition, the chemical functionalization that is facilitated by these functional groups on the GO surface resulted in the enhancement of dispersibility and corrosion protection performance. Hence, the GO-based polymer coatings have attracted significant attention globally especially in the corrosion industry. Although, the electrochemical characteristics of GO-polymer nanocomposite coatings have not been explored much. Therefore, in this study, a series of coatings were developed by incorporating various amounts of GO nanoparticles into the polymer matrix. These coatings were then coated on the steel substrates and the barrier protection performance of GO-based coatings was investigated using electrochemical impedance spectroscopy (EIS). In addition, the electrochemical activity was observed by determining the breakpoint frequencies (<span><math><mrow><msub><mi>f</mi><mi>b</mi></msub></mrow></math></span>) over a period of 90 days. The results revealed that the incorporation of GO nanoparticles significantly enhanced the corrosion protection performance of the coatings. The results demonstrated that the best corrosion resistance was achieved by the 0.5 % GO coating sample. Fourier transform infrared (FTIR) spectroscopy was employed to verify the chemical structure of the composite coatings.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"73 ","pages":"Pages 98-111"},"PeriodicalIF":2.4,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143620891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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