Pub Date : 2025-04-03DOI: 10.1016/j.optmat.2025.117018
Feihong Yang , Weiwei Li , Peng Luo , Jing Cheng , Laiming Chen
Transparent Yb:CaF2 ceramics have recently emerged as a promising ultra-fast laser medium with broad emission bandwidth, long lifetime and suitable thermal properties. However, Yb3+ clustering in the CaF2 host strongly influences the performance of these materials as solid-state laser gain media, and mitigating this clustering remains a challenge. Herein, we introduced Y3+ and Gd3+ buffer ions simultaneously for the first time to modulate the fluorescence properties of transparent Yb:CaF2 ceramics and explore the effect of Y3+ and Gd3+ ions co-doping on the optical quality and microstructure of the ceramics. It was found that transmittance in the short wavelength was improved and fluorescence properties could be modulated to a larger extent compared to single buffer ion doping. This finding establishes the correlation between the double buffer ions doping and the fluorescence properties in transparent Yb:CaF2 ceramics, and may lead to innovative techniques of transmitting enhancement, as well as its ultrafast laser applications.
{"title":"Fabrication and spectral properties of Y3+ and Gd3+ ions co-doped transparent Yb:CaF2 ceramics","authors":"Feihong Yang , Weiwei Li , Peng Luo , Jing Cheng , Laiming Chen","doi":"10.1016/j.optmat.2025.117018","DOIUrl":"10.1016/j.optmat.2025.117018","url":null,"abstract":"<div><div>Transparent Yb:CaF<sub>2</sub> ceramics have recently emerged as a promising ultra-fast laser medium with broad emission bandwidth, long lifetime and suitable thermal properties. However, Yb<sup>3+</sup> clustering in the CaF<sub>2</sub> host strongly influences the performance of these materials as solid-state laser gain media, and mitigating this clustering remains a challenge. Herein, we introduced Y<sup>3+</sup> and Gd<sup>3+</sup> buffer ions simultaneously for the first time to modulate the fluorescence properties of transparent Yb:CaF<sub>2</sub> ceramics and explore the effect of Y<sup>3+</sup> and Gd<sup>3+</sup> ions co-doping on the optical quality and microstructure of the ceramics. It was found that transmittance in the short wavelength was improved and fluorescence properties could be modulated to a larger extent compared to single buffer ion doping. This finding establishes the correlation between the double buffer ions doping and the fluorescence properties in transparent Yb:CaF<sub>2</sub> ceramics, and may lead to innovative techniques of transmitting enhancement, as well as its ultrafast laser applications.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"163 ","pages":"Article 117018"},"PeriodicalIF":3.8,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143785578","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 : 2025-04-02DOI: 10.1016/j.optmat.2025.117013
Guodi Zhang, Hang Guo, Xinyue Ma, Zhuoran Jia, Wenzhi Wu, Jianhui Sun
The CuInS2 quantum dots (QDs) exhibit exceptional potential in semiconductor light-emitting diodes and photovoltaic devices. Investigating their fundamental excitonic photophysical processes involving the recombination dynamics and exciton−phonon coupling is crucial for advancing their applications. Type-I CuInS2/ZnS and type-II CuInS2/CdS core/shell QDs were synthesized to investigate the impact of excitonic wavefunction-distribution on carrier dynamics and exciton-phonon interaction by femtosecond transient-absorption-spectroscopy (fs-TAS) and temperature-dependent photoluminescence spectroscopy (TD-PLS), respectively. The synthesized CuInS2/CdS core/shell QDs have a notably longer PL lifetime than that of CuInS2/ZnS core/shell QDs due to their type-II exciton confinement, in consistent with the theoretical calculations based on the model of spherical box with finite potential barrier. However, in the analysis of ultrafast fs-TAS dynamics, the CuInS2/CdS core/shell QDs exhibit short excited-state lifetimes, primarily due to the elevated density of defect states. These defect states exhibit a significant thermal PL quenching effect by our TD-PLS analysis, where thermal activation energy of CuInS2/CdS core/shell QDs is determined to be 40.1 meV, lower than that of CuInS2/ZnS core/shell QDs (68.7 meV). This is ascribed to expanding of the electron wavefunction from CuInS2 core to CdS shell, making electron transitions susceptible to the influence of interface defects and surface defects. Correspondingly, the evolution trend of PL lifetime on CuInS2/CdS core/shell QDs with the temperature exhibits two parts which are attributed to thermal activation of interface defects and surface defects, respectively. These results suggest the wavefunction engineering can be employed to regulate the excitonic photophysical processes of QDs for their potential applications.
{"title":"Wavefunction engineering for regulation of recombination dynamics and exciton-phonon coupling in CuInS2 quantum dots","authors":"Guodi Zhang, Hang Guo, Xinyue Ma, Zhuoran Jia, Wenzhi Wu, Jianhui Sun","doi":"10.1016/j.optmat.2025.117013","DOIUrl":"10.1016/j.optmat.2025.117013","url":null,"abstract":"<div><div>The CuInS<sub>2</sub> quantum dots (QDs) exhibit exceptional potential in semiconductor light-emitting diodes and photovoltaic devices. Investigating their fundamental excitonic photophysical processes involving the recombination dynamics and exciton−phonon coupling is crucial for advancing their applications. Type-I CuInS<sub>2</sub>/ZnS and type-II CuInS<sub>2</sub>/CdS core/shell QDs were synthesized to investigate the impact of excitonic wavefunction-distribution on carrier dynamics and exciton-phonon interaction by femtosecond transient-absorption-spectroscopy (fs-TAS) and temperature-dependent photoluminescence spectroscopy (TD-PLS), respectively. The synthesized CuInS<sub>2</sub>/CdS core/shell QDs have a notably longer PL lifetime than that of CuInS<sub>2</sub>/ZnS core/shell QDs due to their type-II exciton confinement, in consistent with the theoretical calculations based on the model of spherical box with finite potential barrier. However, in the analysis of ultrafast fs-TAS dynamics, the CuInS<sub>2</sub>/CdS core/shell QDs exhibit short excited-state lifetimes, primarily due to the elevated density of defect states. These defect states exhibit a significant thermal PL quenching effect by our TD-PLS analysis, where thermal activation energy of CuInS<sub>2</sub>/CdS core/shell QDs is determined to be 40.1 meV, lower than that of CuInS<sub>2</sub>/ZnS core/shell QDs (68.7 meV). This is ascribed to expanding of the electron wavefunction from CuInS<sub>2</sub> core to CdS shell, making electron transitions susceptible to the influence of interface defects and surface defects. Correspondingly, the evolution trend of PL lifetime on CuInS<sub>2</sub>/CdS core/shell QDs with the temperature exhibits two parts which are attributed to thermal activation of interface defects and surface defects, respectively. These results suggest the wavefunction engineering can be employed to regulate the excitonic photophysical processes of QDs for their potential applications.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"163 ","pages":"Article 117013"},"PeriodicalIF":3.8,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143785582","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 reports the fabrication of an FTO/C–TiO2/M-TiO2/CH3NH3PbI3/Spiro-MeOTAD/Au perovskite solar cell and investigates its stability under various environmental conditions. The degraded perovskite layer is shown to be recoverable under high humidity in dark conditions. A 15 % RH nitrogen (N2) flow effectively removes oxygen (O2) and water (H2O) molecules from the Spiro-MeOTAD/perovskite interface, enabling rapid recovery of the interface and enhancing the device's current density. The perovskite material exhibits temperature-dependent stability, achieving an efficiency of 20.24 % at 300 K with a fill factor of 86.88 %, JSC of 24.77 mA/cm2, and VOC of 0.94 V. High humidity induces trap states, lowering the photocurrent, whereas low humidity stabilizes the material. The 1/f noise measurements reveal critical insights into defect states in the perovskite layer: high humidity correlates with reduced noise, while low humidity leads to increased noise levels. The effects of humidity, temperature, UV light, and white light on defect states are further analyzed using 1/f noise spectra and I–V characteristics under white light illumination and dark conditions.
{"title":"Fabrication and characterization of FTO/C–TiO2/M-TiO2/CH3NH3PbI3/Spiro-MeOTAD/Au perovskite solar cell: Effect of moisture on stability and study of noise spectroscopy","authors":"Amrit Kumar Mishra , Vijay Kumar Mishra , Rajesh Kumar Shukla","doi":"10.1016/j.optmat.2025.117016","DOIUrl":"10.1016/j.optmat.2025.117016","url":null,"abstract":"<div><div>This study reports the fabrication of an FTO/C–TiO<sub>2</sub>/M-TiO<sub>2</sub>/CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub>/Spiro-MeOTAD/Au perovskite solar cell and investigates its stability under various environmental conditions. The degraded perovskite layer is shown to be recoverable under high humidity in dark conditions. A 15 % RH nitrogen (N<sub>2</sub>) flow effectively removes oxygen (O<sub>2</sub>) and water (H<sub>2</sub>O) molecules from the Spiro-MeOTAD/perovskite interface, enabling rapid recovery of the interface and enhancing the device's current density. The perovskite material exhibits temperature-dependent stability, achieving an efficiency of 20.24 % at 300 K with a fill factor of 86.88 %, J<sub>SC</sub> of 24.77 mA/cm<sup>2</sup>, and V<sub>OC</sub> of 0.94 V. High humidity induces trap states, lowering the photocurrent, whereas low humidity stabilizes the material. The 1/f noise measurements reveal critical insights into defect states in the perovskite layer: high humidity correlates with reduced noise, while low humidity leads to increased noise levels. The effects of humidity, temperature, UV light, and white light on defect states are further analyzed using 1/f noise spectra and I–V characteristics under white light illumination and dark conditions.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"163 ","pages":"Article 117016"},"PeriodicalIF":3.8,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143783927","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}
Metasurface is a kind artificial composite composed of subwavelength structures arranged for novel optical properties. Here we propose and demonstrate a metasurface made of hybrid metal-graphene structure for electrically tunable dual-band electromagnetic extraordinary optical transmission (EOT). Considering the tunability of the conductivity of graphene with applied voltage as well as the freely designed EOT operating in independent frequency bands, the transmission of the dual-band EOT can be efficiently controlled by tuning the biasing voltage on the graphene layer. The electrical tunability of the dual-band EOT behavior is confirmed by full-wave simulation and experimental characterization. The measured results show that the designed metasurface achieves 57.6 % and 32.2 % transmittance at 9.49 GHz and 11.47 GHz, respectively, and 45.7 % and 28 % modulation are achieved when the graphene is biased. The proposed hybrid metasurface enriches the modulation mechanism of electromagnetic EOT behavior through tunable properties of graphene and has certain application prospects in sensors and filter devices.
{"title":"Electrically tunable dual-band extraordinary transmission with a graphene hybrid metasurface","authors":"Yujing Zhang, Jiameng Nan, Weiqi Cai, Jing Xu, Hongkui Shi, Fuli Zhang, Yuancheng Fan","doi":"10.1016/j.optmat.2025.117014","DOIUrl":"10.1016/j.optmat.2025.117014","url":null,"abstract":"<div><div>Metasurface is a kind artificial composite composed of subwavelength structures arranged for novel optical properties. Here we propose and demonstrate a metasurface made of hybrid metal-graphene structure for electrically tunable dual-band electromagnetic extraordinary optical transmission (EOT). Considering the tunability of the conductivity of graphene with applied voltage as well as the freely designed EOT operating in independent frequency bands, the transmission of the dual-band EOT can be efficiently controlled by tuning the biasing voltage on the graphene layer. The electrical tunability of the dual-band EOT behavior is confirmed by full-wave simulation and experimental characterization. The measured results show that the designed metasurface achieves 57.6 % and 32.2 % transmittance at 9.49 GHz and 11.47 GHz, respectively, and 45.7 % and 28 % modulation are achieved when the graphene is biased. The proposed hybrid metasurface enriches the modulation mechanism of electromagnetic EOT behavior through tunable properties of graphene and has certain application prospects in sensors and filter devices.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"163 ","pages":"Article 117014"},"PeriodicalIF":3.8,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143747965","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}
Recently, the application of rare earth elements in LEDs has attracted widespread attention. This article conducts in-depth research on rare earth fluorescent nanofiber membrane materials. Firstly, Eu3+, 2-thenoyltrifluomacetonate (tta), and 1,10-phenanthroline (Phen) undergo a complexation reaction to form the Eu(tta)3Phen complexes. The highly efficient fluorescent hybrid material SiO2@Eu(tta)3Phen prepared by using a straightforward doping method to mix the Eu(tta)3phen complexes with synthetic silica nanoparticles. Fluorescent nanofiber membranes that emit uniform red light was prepared by loading SiO2@Eu(tta)3Phen onto PVA nanofiber membrane (PNM) and SiO2 nanofiber film (SNF) by filtration. After calculation, the loading amount of FSNF and FPNM were 55.6 % and 38.4 %, respectively. It was found that SiO2 fluorescent nanofiber film (FSNF) had better fluorescence performance than PVA fluorescent nanofiber membrane (FPNM) under excitation at 384 nm wavelength. FSNF and FPNM were applied to LED components, both of which exhibited excellent fluorescence. The chromaticity coordinate (x, y) of FSNF is (0.6545, 0.3418), the correlated color temperature (CCT) is 1000K. The chromaticity coordinate (x, y) of FPNM is (0.6496, 0.3396), with a correlated color temperature (CCT) of 1000K. However, FSNF has a significant improvement in the persistence of ultraviolet irradiation compared to FPNM. These findings demonstrate that the developed FSNF have tremendous potential in white LEDs.
{"title":"SiO2 fluorescent nanofiber film incorporating Eu3+-doped for inorganic red light-emitting diode","authors":"Leixuan Li, Yanxin Wang, Wei Xing, Xiaotong Zhang, Hanwen Wang, Huiyi Wu, Jian Wang, Linjun Huang, Jianguo Tang","doi":"10.1016/j.optmat.2025.117009","DOIUrl":"10.1016/j.optmat.2025.117009","url":null,"abstract":"<div><div>Recently, the application of rare earth elements in LEDs has attracted widespread attention. This article conducts in-depth research on rare earth fluorescent nanofiber membrane materials. Firstly, Eu<sup>3+</sup>, 2-thenoyltrifluomacetonate (tta), and 1,10-phenanthroline (Phen) undergo a complexation reaction to form the Eu(tta)<sub>3</sub>Phen complexes. The highly efficient fluorescent hybrid material SiO<sub>2</sub>@Eu(tta)<sub>3</sub>Phen prepared by using a straightforward doping method to mix the Eu(tta)<sub>3</sub>phen complexes with synthetic silica nanoparticles. Fluorescent nanofiber membranes that emit uniform red light was prepared by loading SiO<sub>2</sub>@Eu(tta)<sub>3</sub>Phen onto PVA nanofiber membrane (PNM) and SiO<sub>2</sub> nanofiber film (SNF) by filtration. After calculation, the loading amount of FSNF and FPNM were 55.6 % and 38.4 %, respectively. It was found that SiO<sub>2</sub> fluorescent nanofiber film (FSNF) had better fluorescence performance than PVA fluorescent nanofiber membrane (FPNM) under excitation at 384 nm wavelength. FSNF and FPNM were applied to LED components, both of which exhibited excellent fluorescence. The chromaticity coordinate (x, y) of FSNF is (0.6545, 0.3418), the correlated color temperature (CCT) is 1000K. The chromaticity coordinate (<em>x</em>, <em>y</em>) of FPNM is (0.6496, 0.3396), with a correlated color temperature (CCT) of 1000K. However, FSNF has a significant improvement in the persistence of ultraviolet irradiation compared to FPNM. These findings demonstrate that the developed FSNF have tremendous potential in white LEDs.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"163 ","pages":"Article 117009"},"PeriodicalIF":3.8,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739009","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 : 2025-03-28DOI: 10.1016/j.optmat.2025.117008
Yi Shi , Lizhi Fang , Haiping Xia , Hongwei Song , Baojiu Chen
A hitherto undeveloped Pr3+/Ho3+: LiYF4 single crystal by introducing non-active Lu3+ ions was synthesized by a reformative Bridgman technique. The crystalline phases and optical properties of the crystals were characterized using various methods, including absorption spectra, X-ray diffraction (XRD), Rietveld refinement, emission spectra, and lifetimes. The band gaps of Ho3+/Pr3+: LiYF4 (Ho3+/Pr3+: LYF) and Ho3+/Pr3+/Lu3+: LiYF4 (Ho3+/Pr3+: LLYF) single crystal were calculated by density functional theory, the value is ∼7.902 eV and ∼7.692 eV, respectively. The ∼2.9 μm emission intensity significantly increased about two times when Lu3+ (3.0 mol%) was added to 0.1Pr3+/0.5Ho3+: LiYF4single crystal due to the disruption of [Ho3+-Ho3+] quenching clusters formed by Ho3+ ions. The maximum emission cross section of 0.1Pr3+/0.5Ho3/3.0Lu3+: LiYF4 single crystal was ∼22.7 × 10−21 cm2. The doping of Lu3+ ions reduced significantly the lifetime of 5I7 energy level and mitigates effectively the self-termination phenomenon. Thus, the incorporation of Pr3+/Ho3+/Lu3+ into LiYF4 single crystal represented a promising choice for a laser gain medium operating at ∼2.9 μm, as well as for other optoelectronic devices.
{"title":"Enhanced and modulated ∼2.9 μm mid-infrared emission of Ho3+/Pr3+: LiYF4 single crystal by co-doping non active Lu3+ ions","authors":"Yi Shi , Lizhi Fang , Haiping Xia , Hongwei Song , Baojiu Chen","doi":"10.1016/j.optmat.2025.117008","DOIUrl":"10.1016/j.optmat.2025.117008","url":null,"abstract":"<div><div>A hitherto undeveloped Pr<sup>3+</sup>/Ho<sup>3+</sup>: LiYF<sub>4</sub> single crystal by introducing non-active Lu<sup>3+</sup> ions was synthesized by a reformative Bridgman technique. The crystalline phases and optical properties of the crystals were characterized using various methods, including absorption spectra, X-ray diffraction (XRD), Rietveld refinement, emission spectra, and lifetimes. The band gaps of Ho<sup>3+</sup>/Pr<sup>3+</sup>: LiYF<sub>4</sub> (Ho<sup>3+</sup>/Pr<sup>3+</sup>: LYF) and Ho<sup>3+</sup>/Pr<sup>3+</sup>/Lu<sup>3+</sup>: LiYF<sub>4</sub> (Ho<sup>3+</sup>/Pr<sup>3+</sup>: LLYF) single crystal were calculated by density functional theory, the value is ∼7.902 eV and ∼7.692 eV, respectively. The ∼2.9 μm emission intensity significantly increased about two times when Lu<sup>3+</sup> (3.0 mol%) was added to 0.1Pr<sup>3+</sup>/0.5Ho<sup>3+</sup>: LiYF<sub>4</sub>single crystal due to the disruption of [Ho<sup>3+</sup>-Ho<sup>3+</sup>] quenching clusters formed by Ho<sup>3+</sup> ions. The maximum emission cross section of 0.1Pr<sup>3+</sup>/0.5Ho<sup>3</sup>/3.0Lu<sup>3+</sup>: LiYF<sub>4</sub> single crystal was ∼22.7 × 10<sup>−21</sup> cm<sup>2</sup>. The doping of Lu<sup>3+</sup> ions reduced significantly the lifetime of <sup>5</sup>I<sub>7</sub> energy level and mitigates effectively the self-termination phenomenon. Thus, the incorporation of Pr<sup>3+</sup>/Ho<sup>3+</sup>/Lu<sup>3+</sup> into LiYF<sub>4</sub> single crystal represented a promising choice for a laser gain medium operating at ∼2.9 μm, as well as for other optoelectronic devices.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"163 ","pages":"Article 117008"},"PeriodicalIF":3.8,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739132","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 : 2025-03-28DOI: 10.1016/j.optmat.2025.116977
Mohamed S.I. Koubisy , Wael Mohammed , Fatemah H. Alkallas , Amira Ben Gouider Trabelsi , Shoroog Alraddadi , Abdelaziz M. Aboraia
In the presented work, the influence of Sn doping on structural, morphological, and optical properties is systematically investigated. In this regard, in order to overcome such drawbacks, Sn was incorporated into the LiCoPO4 matrix through a solid-state synthesis route by varying the Sn concentration from 0 to 8 mol%. XRD recorded the structural changes upon Sn doping, which indicated that Sn incorporation did not change the LiCoPO4 primary orthorhombic olivine structure, though inducing minor changes in the lattice parameters due to the radius difference between Sn4+ and Co2+. TEM studies were performed to investigate the morphological properties. The optical properties were studied by UV–Vis spectrophotometer and showed a gradual decrease of the optical bandgap with increasing Sn content, the highest bandgap (3.94 eV) was obtained for x = 0 of Sn while the lowest value of band gap (3.64) was obtained for x = 0.08 of Sn. The refractive index decreased with an increase in the concentrations of Sn, 1.8 to 1.6 respectively. The non-linear absorption coefficient increases with Sn doping. Thus, these findings provide a new route to modify the properties of LiCoPO4 for energy storage and also manifest Sn as a potential dopant for enhancing the performances of transition metal phosphates, particularly in various technological uses. This study therefore paves the way for further optimization of LiCoPO4 and similar materials for high-performance batteries and other functional devices.
{"title":"Effect of Sn on the structural, morphological and optical properties of liCoPO4","authors":"Mohamed S.I. Koubisy , Wael Mohammed , Fatemah H. Alkallas , Amira Ben Gouider Trabelsi , Shoroog Alraddadi , Abdelaziz M. Aboraia","doi":"10.1016/j.optmat.2025.116977","DOIUrl":"10.1016/j.optmat.2025.116977","url":null,"abstract":"<div><div>In the presented work, the influence of Sn doping on structural, morphological, and optical properties is systematically investigated. In this regard, in order to overcome such drawbacks, Sn was incorporated into the LiCoPO<sub>4</sub> matrix through a solid-state synthesis route by varying the Sn concentration from 0 to 8 mol%. XRD recorded the structural changes upon Sn doping, which indicated that Sn incorporation did not change the LiCoPO<sub>4</sub> primary orthorhombic olivine structure, though inducing minor changes in the lattice parameters due to the radius difference between Sn<sup>4+</sup> and Co<sup>2+</sup>. TEM studies were performed to investigate the morphological properties. The optical properties were studied by UV–Vis spectrophotometer and showed a gradual decrease of the optical bandgap with increasing Sn content, the highest bandgap (3.94 eV) was obtained for x = 0 of Sn while the lowest value of band gap (3.64) was obtained for x = 0.08 of Sn. The refractive index decreased with an increase in the concentrations of Sn, 1.8 to 1.6 respectively. The non-linear absorption coefficient increases with Sn doping. Thus, these findings provide a new route to modify the properties of LiCoPO<sub>4</sub> for energy storage and also manifest Sn as a potential dopant for enhancing the performances of transition metal phosphates, particularly in various technological uses. This study therefore paves the way for further optimization of LiCoPO<sub>4</sub> and similar materials for high-performance batteries and other functional devices.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"163 ","pages":"Article 116977"},"PeriodicalIF":3.8,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143747962","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 : 2025-03-28DOI: 10.1016/j.optmat.2025.116965
Diego Pérez-Francés , Fernando Rodríguez , Rafael Valiente
In 1988, McCarthy and Güdel published the seminal review Optical Spectroscopy of Exchange-Coupled Transition Metal Complexes, which not only compiled key spectroscopic results but also provided a deep insight into the theoretical foundations of the field, originally developed by Tanabe in the 1960s, which is undoubtedly the most insightful review in this topic to date. The work presented here aims to pay a modest tribute to Prof. Hans U. Güdel for his outstanding contributions and career — a scientist who was a guiding figure for many of us entering the field of spectroscopy. This review provides an updated overview of key experimental findings where exchange-coupled systems play a fundamental role, many of which involved direct contributions from Prof. Güdel himself. We begin by discussing homonuclear transition-metal systems, such as Mn–Mn and Mn–Mn pairs, highlighting the unique features of their absorption and emission spectra, as well as their lifetimes — phenomena that are not observed in isolated ions. The discussion then extends to heteronuclear mixed-metal systems, specifically transition-metal/rare-earth ion pairs, such as Mn–Yb. In these systems, a novel upconversion luminescence mechanism was proposed, based on exchange interaction via the Tanabe mechanism between Yb and Mn. Significant enhancement of optical absorption and its temperature dependence was attributed to Mn–Cu exchange interaction units. Finally, we compare results from two Ni-doped isostructural materials — RbCdCl and RbMnCl — emphasizing the potential of exchange coupling mechanism to enhance luminescence efficiency.
{"title":"Optical spectroscopy of exchange-coupled ions: Insights into homonuclear, heteronuclear and mixed transition-metal/rare-earth systems","authors":"Diego Pérez-Francés , Fernando Rodríguez , Rafael Valiente","doi":"10.1016/j.optmat.2025.116965","DOIUrl":"10.1016/j.optmat.2025.116965","url":null,"abstract":"<div><div>In 1988, McCarthy and Güdel published the seminal review <em>Optical Spectroscopy of Exchange-Coupled Transition Metal Complexes</em>, which not only compiled key spectroscopic results but also provided a deep insight into the theoretical foundations of the field, originally developed by Tanabe in the 1960s, which is undoubtedly the most insightful review in this topic to date. The work presented here aims to pay a modest tribute to Prof. Hans U. Güdel for his outstanding contributions and career — a scientist who was a guiding figure for many of us entering the field of spectroscopy. This review provides an updated overview of key experimental findings where exchange-coupled systems play a fundamental role, many of which involved direct contributions from Prof. Güdel himself. We begin by discussing homonuclear transition-metal systems, such as Mn<span><math><msup><mrow></mrow><mrow><mn>2</mn><mo>+</mo></mrow></msup></math></span>–Mn<span><math><msup><mrow></mrow><mrow><mn>2</mn><mo>+</mo></mrow></msup></math></span> and Mn<span><math><msup><mrow></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></math></span>–Mn<span><math><msup><mrow></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></math></span> pairs, highlighting the unique features of their absorption and emission spectra, as well as their lifetimes — phenomena that are not observed in isolated ions. The discussion then extends to heteronuclear mixed-metal systems, specifically transition-metal/rare-earth ion pairs, such as Mn<span><math><msup><mrow></mrow><mrow><mn>2</mn><mo>+</mo></mrow></msup></math></span>–Yb<span><math><msup><mrow></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></math></span>. In these systems, a novel upconversion luminescence mechanism was proposed, based on exchange interaction via the Tanabe mechanism between Yb<span><math><msup><mrow></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></math></span> and Mn<span><math><msup><mrow></mrow><mrow><mn>2</mn><mo>+</mo></mrow></msup></math></span>. Significant enhancement of optical absorption and its temperature dependence was attributed to Mn<span><math><msup><mrow></mrow><mrow><mn>2</mn><mo>+</mo></mrow></msup></math></span>–Cu<span><math><msup><mrow></mrow><mrow><mn>2</mn><mo>+</mo></mrow></msup></math></span> exchange interaction units. Finally, we compare results from two Ni<span><math><msup><mrow></mrow><mrow><mn>2</mn><mo>+</mo></mrow></msup></math></span>-doped isostructural materials — Rb<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>CdCl<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span> and Rb<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>MnCl<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span> — emphasizing the potential of exchange coupling mechanism to enhance luminescence efficiency.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"163 ","pages":"Article 116965"},"PeriodicalIF":3.8,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739011","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 : 2025-03-28DOI: 10.1016/j.optmat.2025.117010
Ahmed Belguenoune , Nadir Ouldhamadouche , Salah Bassaid , Abdelkader Dehbi , Abdallah Ben Rhaiem
This study explores the structural, linear, and nonlinear optical properties of lanthanum orthoferrite (LaFeO3) and the impact of bismuth (Bi) substitution at the A-site in varying concentrations (0.05, 0.1, and 0.15) on these properties. The La1-xBixFeO3 samples were synthesized via the sol-gel method using citric acid as a complexing agent. Structural characterization was conducted using X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). XRD analysis confirmed the formation of a perovskite phase with an orthorhombic structure (Pbnm space group), while Rietveld refinement provided precise crystallographic and geometric parameters. FTIR spectra verified the phase purity, revealing no detectable carboxyl or hydroxyl functional groups, indicating the absence of carbonates and minimal hygroscopicity. UV–visible spectroscopy was employed to assess absorbance and reflectance spectra, Which indicated enhanced absorption in the visible region upon doping. The calculated linear optical parameters stated an increase in bandgap energy from 2.045 eV to 2.139 eV with increasing Bi content, accompanied by a reduction in Urbach energy. Furthermore, Bi-doped samples exhibited anomalous dispersion behavior in the refractive index, in contrast to the normal dispersion observed in undoped LaFeO3. Dielectric properties, optical performance, and electrical conductivity were also improved upon Bi incorporation. The nonlinear optical analysis, including third-order nonlinear susceptibility (χ(3)) and nonlinear refractive index—enables, revealed that pristine LaFeO3 exhibited superior optical characteristics compared to Bi-doped samples.
{"title":"Impact of bismuth substitution on the structural and optical properties of lanthanum orthoferrite synthesized via sol-gel method","authors":"Ahmed Belguenoune , Nadir Ouldhamadouche , Salah Bassaid , Abdelkader Dehbi , Abdallah Ben Rhaiem","doi":"10.1016/j.optmat.2025.117010","DOIUrl":"10.1016/j.optmat.2025.117010","url":null,"abstract":"<div><div>This study explores the structural, linear, and nonlinear optical properties of lanthanum orthoferrite (LaFeO<sub>3</sub>) and the impact of bismuth (Bi) substitution at the A-site in varying concentrations (0.05, 0.1, and 0.15) on these properties. The La<sub>1-x</sub>BixFeO<sub>3</sub> samples were synthesized via the sol-gel method using citric acid as a complexing agent. Structural characterization was conducted using X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). XRD analysis confirmed the formation of a perovskite phase with an orthorhombic structure (Pbnm space group), while Rietveld refinement provided precise crystallographic and geometric parameters. FTIR spectra verified the phase purity, revealing no detectable carboxyl or hydroxyl functional groups, indicating the absence of carbonates and minimal hygroscopicity. UV–visible spectroscopy was employed to assess absorbance and reflectance spectra, Which indicated enhanced absorption in the visible region upon doping. The calculated linear optical parameters stated an increase in bandgap energy from 2.045 eV to 2.139 eV with increasing Bi content, accompanied by a reduction in Urbach energy. Furthermore, Bi-doped samples exhibited anomalous dispersion behavior in the refractive index, in contrast to the normal dispersion observed in undoped LaFeO<sub>3</sub>. Dielectric properties, optical performance, and electrical conductivity were also improved upon Bi incorporation. The nonlinear optical analysis, including third-order nonlinear susceptibility (χ(3)) and nonlinear refractive index—enables, revealed that pristine LaFeO<sub>3</sub> exhibited superior optical characteristics compared to Bi-doped samples.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"163 ","pages":"Article 117010"},"PeriodicalIF":3.8,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760401","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 : 2025-03-28DOI: 10.1016/j.optmat.2025.117006
Fazal Rehman , Salih Yılmaz , İsmail Polat , Emin Bacaksız , Recep Zan , Mehmet Ali Olgar
The study investigated the characterization of photodetectors made from CZTS (Cu2ZnSnS4) thin films by introducing silver (Ag) as a dopant. CZTS thin films were grown on Mo-foil by two stage process, comprising sputter deposition of metallic precursor layers followed by sulfurization process employing Rapid Thermal Annealing (RTA) approach. The stacking order for the undoped and Ag-doped CZTS thin films were Substrate/ZnS/Cu/Sn/Cu and Substrate/ZnS/Cu/Sn/Cu/Ag, respectively. Photodetectors (PDs) were fabricated using sputter deposition on glass, including CZTS, Ag-doped CZTS-5 (8 nm Ag), Ag-doped CZTS-10 (16 nm Ag), and Ag-doped CZTS-15 (24 nm Ag). Various characterization methods were utilized to examine the prepared thin films, including Energy Dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Raman spectroscopy, Scanning Electron Microscopy (SEM), optical transmission, Photoluminescence (PL) and photodetection analyses. Among all devices, Ag-CZTS-10 PDs exhibited the best performance, showing a crystallite size (D) of 51.72 nm, band gap of 1.47 eV and favorable SEM surface morphology. For the photodetection characteristics, blue light at 443 nm and red light at 525 nm wavelength were used with an applied bias of 2V, and a light intensity of 17.3 mW/cm2. The highest responsivity (R) values recorded for Ag-CZTS-10-based PDs were 0.0024 A/W for blue and 0.0019 A/W for red light. Additionally, the detectivity (D∗) was 3.4 × 106 Jones for blue and 2.3 × 106 Jones for red light, while sensitivity (S) was 26 % for blue and 15 % for red light. This study successfully demonstrated, for the first time, the fabrication of low-cost, high-performance Ag-doped CZTS films-based PDs on glass substrates which hold promise for the development of cost-effective and efficient optoelectronic devices.
{"title":"Unveiling improvements in structural, optical, and photodetection characteristics of CZTS thin films through Ag-doping","authors":"Fazal Rehman , Salih Yılmaz , İsmail Polat , Emin Bacaksız , Recep Zan , Mehmet Ali Olgar","doi":"10.1016/j.optmat.2025.117006","DOIUrl":"10.1016/j.optmat.2025.117006","url":null,"abstract":"<div><div>The study investigated the characterization of photodetectors made from CZTS (Cu<sub>2</sub>ZnSnS<sub>4</sub>) thin films by introducing silver (Ag) as a dopant. CZTS thin films were grown on Mo-foil by two stage process, comprising sputter deposition of metallic precursor layers followed by sulfurization process employing Rapid Thermal Annealing (RTA) approach. The stacking order for the undoped and Ag-doped CZTS thin films were Substrate/ZnS/Cu/Sn/Cu and Substrate/ZnS/Cu/Sn/Cu/Ag, respectively. Photodetectors (PDs) were fabricated using sputter deposition on glass, including CZTS, Ag-doped CZTS-5 (8 nm Ag), Ag-doped CZTS-10 (16 nm Ag), and Ag-doped CZTS-15 (24 nm Ag). Various characterization methods were utilized to examine the prepared thin films, including Energy Dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Raman spectroscopy, Scanning Electron Microscopy (SEM), optical transmission, Photoluminescence (PL) and photodetection analyses. Among all devices, Ag-CZTS-10 PDs exhibited the best performance, showing a crystallite size (<em>D</em>) of 51.72 nm, band gap of 1.47 eV and favorable SEM surface morphology. For the photodetection characteristics, blue light at 443 nm and red light at 525 nm wavelength were used with an applied bias of 2V, and a light intensity of 17.3 mW/cm<sup>2</sup>. The highest responsivity (R) values recorded for Ag-CZTS-10-based PDs were 0.0024 A/W for blue and 0.0019 A/W for red light. Additionally, the detectivity (D∗) was 3.4 × 10<sup>6</sup> Jones for blue and 2.3 × 10<sup>6</sup> Jones for red light, while sensitivity (S) was 26 % for blue and 15 % for red light. This study successfully demonstrated, for the first time, the fabrication of low-cost, high-performance Ag-doped CZTS films-based PDs on glass substrates which hold promise for the development of cost-effective and efficient optoelectronic devices.</div></div>","PeriodicalId":19564,"journal":{"name":"Optical Materials","volume":"163 ","pages":"Article 117006"},"PeriodicalIF":3.8,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143747964","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}
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