{"title":"Degradation of crystallinity in tin oxide incorporated with manganese and cobalt synthesized using co-precipitation method","authors":"Karishma Jain , Deepika Maan , Ashish Kumar , Sushil Kumar Jain , Balram Tripathi","doi":"10.1016/j.jlumin.2025.121369","DOIUrl":"10.1016/j.jlumin.2025.121369","url":null,"abstract":"<div><div>Tin oxide (SnO<sub>2</sub>) incorporated with manganese and cobalt atoms has been synthesized using co-precipitation route. Structural characteristics were estimated using X-ray diffraction (XRD) and Transmission electron microscopy (TEM). Optical characteristics were investigated using UV–Visible and Photoluminescence spectroscopy. Morphological properties were investigated using Field emission scanning electron microscopy (FESEM), optical characteristics were investigated using UV–Visible and Photoluminescence spectroscopic techniques, and elemental characteristics were confirmed by using Energy Dispersive X-Ray (EDX) analysis. Incorporation of manganese and cobalt in SnO<sub>2</sub>, degraded the crystallinity. Band gap narrowing was evident from Tauc plot. The morphological and elemental analysis indicated that prepared sample has some agglomeration. The sample showcased good photocatalytic properties under sunlight and degraded rose bengal dye up to 96.08 %.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"286 ","pages":"Article 121369"},"PeriodicalIF":3.3,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144470629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
{"title":"Temperature-dependent photoluminescence and exciton recombination processes in naphthalene/TCNB charge-transfer cocrystal","authors":"Wei-Long Xu, Xiangrun Chen, Qiuyu Gu, Fei Zhao, Yannan Zhang, Yuebin Lian","doi":"10.1016/j.jlumin.2025.121371","DOIUrl":"10.1016/j.jlumin.2025.121371","url":null,"abstract":"<div><div>Cocrystal engineering offers a promising strategy to synthesize materials with novel physicochemical properties by integrating electron-rich donors and electron-deficient acceptors through non-covalent interactions. This work focuses on the preparation and characterization of naphthalene/1,2,4,5-tetracyanobenzene (TCNB) charge-transfer cocrystal using a controlled slow solvent evaporation method. Millimeter-scale cocrystals with preferential growth along the (110) plane were synthesized by mixing equimolar acetonitrile solutions of naphthalene and TCNB. Temperature-dependent photoluminescence (PL) studies demonstrated a significant redshift in emission peaks and a broadening of the full width at half maximum (FWHM) from 122 nm to 173 nm, attributed to enhanced electron-phonon coupling and thermal quenching. An exciton binding energy of 142 meV was derived, supporting efficient radiative recombination. Power-dependent PL spectra revealed exciton annihilation effects under high excitation intensity, suppressing short-wavelength emission. The relatively uniform fluorescence lifetime across the sample was observed in time-resolved fluorescence lifetime imaging (FLIM) image. Two decay components were assigned to localized exciton (14.4 ns) and charge transfer exciton (40.3 ns) recombination. These results highlight the tunable optoelectronic properties of naphthalene/TCNB cocrystals and their potential for applications in light-emitting devices and photonic systems.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"286 ","pages":"Article 121371"},"PeriodicalIF":3.3,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144470628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Madara Klave, Milena Dile, Marija Dunce, Ernests Einbergs, Aleksejs Zolotarjovs
{"title":"Electroluminescence in thick-film devices with ZnS:Mn prepared by microwave-assisted synthesis","authors":"Madara Klave, Milena Dile, Marija Dunce, Ernests Einbergs, Aleksejs Zolotarjovs","doi":"10.1016/j.jlumin.2025.121366","DOIUrl":"10.1016/j.jlumin.2025.121366","url":null,"abstract":"<div><div>Electroluminescent devices are essential components in modern lighting and display technologies, offering uniform and efficient light emission. Research in this field has focused on optimizing luminescent materials such as manganese-doped zinc sulphide (ZnS:Mn), which is prized for its bright emission and environmental compatibility. However, current synthesis methods often struggle with long processing times, poor control over particle size, and phase instability, limiting the performance and scalability of these materials. Here we show that microwave-assisted solvothermal synthesis, followed by a sintering step, enables the production of high-quality ZnS:Mn particles suitable for fabricating efficient alternating current powder electroluminescent (ACPEL) panels. Using this approach, the ZnS:Mn particles predominantly form in a stable crystalline phase with a secondary phase emerging after sintering, as confirmed by X-ray diffraction. Photoluminescence measurements reveal a strong orange-yellow emission, indicating effective Mn<sup>2+</sup> incorporation. ACPEL panels fabricated with these particles exhibit optimal performance with a thin electroluminescent film, achieving peak luminescence under moderate excitation conditions. These findings demonstrate that the refined synthesis method provides uniform particle morphology, enhanced luminescent properties, and reliable device performance. These results advance the field by offering a scalable and energy-efficient route to produce high-performance electroluminescent materials, paving the way for improved lighting and display applications. Immediate implications include the potential for more consistent manufacturing processes and enhanced device longevity in commercial ACPEL systems.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"286 ","pages":"Article 121366"},"PeriodicalIF":3.3,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144313718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Sonia Redhu , Devender Singh , Sofia Malik , Anuj Dalal , Sumit Kumar , Rajender Singh Malik , Parvin Kumar , Jayant Sindhu
{"title":"Designing luminescent Eu(III) complexes with heteroligands: A comprehensive spectroscopic, DFT and Judd-Ofelt study","authors":"Sonia Redhu , Devender Singh , Sofia Malik , Anuj Dalal , Sumit Kumar , Rajender Singh Malik , Parvin Kumar , Jayant Sindhu","doi":"10.1016/j.jlumin.2025.121364","DOIUrl":"10.1016/j.jlumin.2025.121364","url":null,"abstract":"<div><div>This research article explores effective strategies for designing luminescent lanthanide complexes, with a focus on europium (Eu) complexes. Four Eu(III) complexes, designated Eu(TFPD)<sub>3</sub>L, each with octa-coordinated geometry were synthesized using the ligand TFPD: 4,4,4- trifluoro-1-phenyl-1,3-butadionate and various bipyridine derivatives: 5,5ʹ-dibromo-2,2ʹ-bipyridine (B1), 5-bromo-5ʹ-(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl]-2,2ʹ-bipyridine (B2) and 5,5ʹ-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-2,2ʹ-bipyridine (B3). Structural insights were gained through elemental analysis, IR and NMR spectroscopy, while optical and electrochemical studies revealed promising band gap properties, positioning these complexes as potential candidates for semiconducting applications. Eu(III) complexes exhibited intense red emission under photoluminescence analysis, driven by the <sup>5</sup>D<sub>0</sub>→<sup>7</sup>F<sub>2</sub> transition, with accuracy validated <em>via</em> CIE 1931 coordinates. Further, excited-state lifetime studies and Judd-Ofelt parameters provided valuable data on the local environment around the Eu(III) ions, illustrating the role of neutral ligands in enhancing luminescent properties. This study overlays the way for Eu(III) complexes with tailored luminescence, opening new possibilities for advanced optical and electronic applications.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"286 ","pages":"Article 121364"},"PeriodicalIF":3.3,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Xiaolong Yang, Peng Sun, Lin Huang, Chaoyi Zhang, Wudi Wang, Xiaotong Peng, Chenbo Zhang, Jun Xu, Huili Tang, Bo Liu
{"title":"The effect of air annealing on the optical and luminescence properties of Bi-doped β-Ga2O3 single crystals","authors":"Xiaolong Yang, Peng Sun, Lin Huang, Chaoyi Zhang, Wudi Wang, Xiaotong Peng, Chenbo Zhang, Jun Xu, Huili Tang, Bo Liu","doi":"10.1016/j.jlumin.2025.121367","DOIUrl":"10.1016/j.jlumin.2025.121367","url":null,"abstract":"<div><div>β-Ga<sub>2</sub>O<sub>3</sub>, as a highly promising fourth-generation ultra-wide bandgap semiconductor material, can be grown as Bi-doped single crystals using the optical floating zone method. This work investigated the effects of air annealing on the optical and luminescence properties of Bi-doped β-Ga<sub>2</sub>O<sub>3</sub> single crystals. Comparing the as-grown and air-annealed samples revealed that annealing reduced the concentration of V<sub>O</sub> in Bi-doped β-Ga<sub>2</sub>O<sub>3</sub> single crystal through environmental oxygen compensation. After annealing, transmission spectra indicated a significant decrease in carrier concentration, while the PL spectra exhibited enhanced intensity and prolonged decay time, with an increased proportion of GL emission, attributed to the increase in V<sub>Ga</sub>. This phenomenon is due to the effective suppression of Auger recombination by the reduced carrier concentration, thereby enhancing the radiative recombination-dominated luminescence process. These findings not only elucidate the effect of annealing on the optical properties of Bi-doped β-Ga<sub>2</sub>O<sub>3</sub> single crystals but also further expand our understanding of their recombination transitions.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"286 ","pages":"Article 121367"},"PeriodicalIF":3.3,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144313719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
C. Aparna , M.G. Mahesha , N. Karunakara , I. Yashodhara , Pramoda Kumara Shetty
{"title":"Enhancement of gamma radiation sensitivity in tungsten-doped indium oxide thin films","authors":"C. Aparna , M.G. Mahesha , N. Karunakara , I. Yashodhara , Pramoda Kumara Shetty","doi":"10.1016/j.jlumin.2025.121368","DOIUrl":"10.1016/j.jlumin.2025.121368","url":null,"abstract":"<div><div>This paper reports on enhancement of gamma sensitivity in indium oxide doped with tungsten. Using the spray pyrolysis process, the thin films are deposited on a heated glass substrate. Gamma doses ranging from 25, 50, 100 and 200 Gy were utilized. According to XRD analysis, the films showed a single-phase and polycrystalline cubic structure with (400) preferred orientation. FESEM was used to conduct morphological studies. The cubic crystalline structure of the deposits is further supported by the micro-Raman measurement. After irradiation, it was discovered that the optical bandgap shrank. The dominant process of defect generation is responsible for the rise in the photoluminescence peak intensities following gamma exposure. The irradiated film was studied for thermoluminescence and deconvolution of the experimental glow curve indicated the emergence of a new peak corresponding to the dopant along with the primary peak around 230 °C. The elements contained in the sample are identified using XPS. The oxygen vacancies produced during gamma exposure determine the structural, optical, and electrical characteristics. The estimated sensitivities for applied voltages ranging from 1 V to 5 V fall within the range of 92.3–467.9 mA/cm<sup>2</sup>/Gy, exceeding both pristine and previously reported values.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"286 ","pages":"Article 121368"},"PeriodicalIF":3.3,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144306298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Jianliang Bai , Xuejia Zhang , Zidan Yin , Yanru Liu , Longlong Ma , Mengzhao Li , Cuixing Xu , Runfang Pei , Lili Ren
{"title":"Concentration-dependent and color-tunable room temperature afterglow of carbon dots@boric acid composites","authors":"Jianliang Bai , Xuejia Zhang , Zidan Yin , Yanru Liu , Longlong Ma , Mengzhao Li , Cuixing Xu , Runfang Pei , Lili Ren","doi":"10.1016/j.jlumin.2025.121365","DOIUrl":"10.1016/j.jlumin.2025.121365","url":null,"abstract":"<div><div>Color-tunable room temperature afterglow (RTA) materials have become excellent candidates for a wide range of applications in information encryption and anti-counterfeiting. However, the achievement of color-tunable afterglow materials in a simple way remains a considerable challenge. In recent years, carbon dots (CDs) have attracted more and more attention in preparing metal-free long afterglow materials. Herein, a convenient and low-cost strategy with different doping concentrations for the preparation of carbon dots@boric acid (CDs@BA) composites with ultralong lifetime RTA has been proposed. Excitingly, the CDs@BA-(Ⅰ, Ⅱ, Ⅲ and Ⅳ) composites not only have ultralong afterglow lifetimes, but also exhibit color-tunable properties ranging from turquoise to deep yellow afterglow. In addition, these CDs@BA composites have been successfully used in the optical pattern design of safety exit signs and hazardous material signs. These findings may provide a new approach for the design of CDs-based nanomaterials with ultralong and color-tunable afterglow under ambient conditions.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"286 ","pages":"Article 121365"},"PeriodicalIF":3.3,"publicationDate":"2025-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144279722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Xue Sun , Yaochuan Wang , Haoran Ni , Ding Zhang , Yizhuo Wang , Yu Li , Dajun Liu , Xuesong Xu , Xiaoqiang Yu
{"title":"Study on charge transfer and photoabsorption characteristics of N-methylpyridinium iodide salt fluorescence probes","authors":"Xue Sun , Yaochuan Wang , Haoran Ni , Ding Zhang , Yizhuo Wang , Yu Li , Dajun Liu , Xuesong Xu , Xiaoqiang Yu","doi":"10.1016/j.jlumin.2025.121362","DOIUrl":"10.1016/j.jlumin.2025.121362","url":null,"abstract":"<div><div>To investigate the effect of charge transfer on photoabsorption characteristics of N-methylpyridinium iodide salt-based fluorescence probes, 9B-MVC of asymmetric D-π-A structure together with symmetric A-π-D-π-A structural 9E-BMVC have been investigated using a combination of experimental and theoretical methods. TPA cross-section of symmetric structural 9E-BMVC measured by femtosecond open-aperture Z-scan at 800 nm is 3.3 times larger than that of the asymmetric conjugated structural 9B-MVC, which indicates that the symmetric conjugated structure with two D-π-A subunits obtains great nonlinear enhancement of two-photon absorption (TPA) response, which is closely related to the longer conjugation length. In addition, TPA spectra calculated by Sum-Over-States (SOS) model also indicates obvious redshit, which effective expands the response wavelength region of the N-methylpyridinium iodide salt probes. The excitation processes of the primary states have been visualized in transition density matrix (TDM) and charge density difference (CDD) heatmaps, strong coupling interactions between two D-π-A subunits have been approved in the symmetric A-π-D-π-A structural N-methylphridinium iodide salt fluorescence probe, which is also an important reason for the great nonlinear enhancement of TPA response.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"286 ","pages":"Article 121362"},"PeriodicalIF":3.3,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144322007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Akshay Pimpalkar , Rajesh M. Bhagat , Shruti P. Dhale , Ashok A. Mistry , Nilesh S. Ugemuge , Rujuta Joshi , R. Nithya , Prachita A. Patil , K.M. Nissamudeen
{"title":"Synthesis and spectroscopic analysis in Ca3NbGa3Si2O14: Ln3+(Ln= Sm,Tb) phosphor for optical applications","authors":"Akshay Pimpalkar , Rajesh M. Bhagat , Shruti P. Dhale , Ashok A. Mistry , Nilesh S. Ugemuge , Rujuta Joshi , R. Nithya , Prachita A. Patil , K.M. Nissamudeen","doi":"10.1016/j.jlumin.2025.121363","DOIUrl":"10.1016/j.jlumin.2025.121363","url":null,"abstract":"<div><div>The orange red emitting Ca<sub>3</sub>NbGa<sub>3</sub>Si<sub>2</sub>O<sub>14</sub>: Sm<sup>3+</sup>, Tb<sup>3+</sup> phosphor was synthesized by solid-state reaction (SSR) method at 1280 °C for 10 h followed by annealing at 400 °C for 7hrs. X-ray diffraction pattern confirms the hexagonal structure with <em>P</em>321(No.150) space group. Compound formation, elemental analysis, photoluminescence and energy transfer mechanism from Tb<sup>3+</sup> to Sm<sup>3+</sup> were studied. Ca<sub>3</sub>NbGa<sub>3</sub>Si<sub>2</sub>O<sub>14</sub>:Sm<sup>3+</sup> phosphor exhibits orange-red emission at 601 nm attributed to <sup>4</sup>G<sub>5/2</sub><span><math><mrow><mo>→</mo></mrow></math></span><sup>6</sup>H<sub>7/2</sub> transition. Ca<sub>3</sub>NbGa<sub>3</sub>Si<sub>2</sub>O<sub>14</sub>:Tb<sup>3+</sup> phosphor exhibits green emission at 544 nm attributed to <sup>5</sup>D<sub>4</sub> <span><math><mrow><mo>→</mo></mrow></math></span> <sup>7</sup>F<sub>5</sub> transition. The optimum concentration for Sm<sup>3+</sup> and Tb<sup>3+</sup> is found to be 3.0 and 2.0 mol. % respectively. Lifetime decay measurements of Tb<sup>3+</sup> confirms the energy transfer mechanism which was proved to be a quadrupole-quadrupole interaction. The CIE chromaticity coordinates calculated for Sm<sup>3+</sup> (0.63, 0.37), Tb<sup>3+</sup> (0.27, 0.72) and 2.0 Tb<sup>3+</sup>, ySm<sup>3+</sup> (0.37, 0.40) suggests its potential use for fabrication of optical devices. Higher values of Ω<sub>4</sub> indicate centro-symmetric character of the field experienced by Sm<sup>3+</sup> ions. This confirms that magnetic dipole transitions are dominant over electric dipole transitions which are analogous to the PL results. Since the obtained values of the branching ratios with respect to transition, <sup>4</sup>G<sub>5/2</sub> <span><math><mrow><mo>→</mo></mrow></math></span> <sup>6</sup>H<sub>7/2</sub> are around 50 %, this material can be proposed as a potential laser material having emission wavelength around 601 nm.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"286 ","pages":"Article 121363"},"PeriodicalIF":3.3,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144298906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Mustafa İlhan , Mehmet İsmail Katı , Lütfiye Feray Güleryüz , Sibel Kılıç
{"title":"Judd-Ofelt analysis and structural, morphological, optical characteristics of Eu3+ doped Ca2GdMO6 (M=Nb, Ta) double perovskite phosphors","authors":"Mustafa İlhan , Mehmet İsmail Katı , Lütfiye Feray Güleryüz , Sibel Kılıç","doi":"10.1016/j.jlumin.2025.121361","DOIUrl":"10.1016/j.jlumin.2025.121361","url":null,"abstract":"<div><div>Rare-earth (RE) activated double perovskite phosphors have emerged as promising candidates for advanced optoelectronic applications due to their superior photoluminescence and high quantum efficiency. In this study, the structural, morphological, and spectroscopic properties of Ca<sub>2</sub>Gd<sub>1<em>-x</em></sub>MO<sub>6</sub>:<em>x</em>Eu<sup>3+</sup> (M = Nb, Ta and <em>x</em> = 2.5–50 mol%) double perovskites were systematically investigated to assess their suitability for red-emitting laser phosphor applications. X-ray diffraction (XRD) confirmed a stable single-phase monoclinic structure with successful Eu<sup>3+</sup> substitution at Gd<sup>3+</sup> sites up to 50 mol% for both host lattices. Scanning electron microscopy (SEM) revealed that Ca<sub>2</sub>GdNbO<sub>6</sub>:Eu<sup>3+</sup> formed irregular micron-sized grains, while Ca<sub>2</sub>GdTaO<sub>6</sub>:Eu<sup>3+</sup> developed larger, oval-shaped particles. Photoluminescence measurements showed enhanced emission intensities up to 40 mol% Eu<sup>3+</sup>, followed by quenching at 50 mol% due to concentration quenching effects. Increasing Eu<sup>3+</sup> concentration strengthened the hypersensitive <sup>5</sup>D<sub>0</sub>→<sup>7</sup>F<sub>2</sub> electric dipole transition, reflected in higher asymmetry ratios and increasing Judd–Ofelt parameters (<em>Ω</em><sub>2</sub>, <em>Ω</em><sub>4</sub>), indicating a gradual reduction in local symmetry and ligand electron density. Notably, Ca<sub>2</sub>Gd<sub>0.6</sub>NbO<sub>6</sub>:0.4Eu<sup>3+</sup> exhibited a higher stimulated emission cross-section (71.783 × 10<sup>−22</sup> cm<sup>2</sup>) and optical gain (3.242 × 10<sup>−24</sup> cm<sup>2</sup> s) compared to its Ta-based counterpart, along with superior quantum efficiency (<em>η</em><sub>QE</sub> = 100 %). Good agreement between theoretical and experimental quantum efficiency values (within 0–6 % deviation) validated the Judd–Ofelt analysis. Chromaticity evaluations demonstrated high color purity (∼95 %) and low correlated color temperatures (CCTs), making these materials attractive for warm white and red-light-emitting devices. Overall, the results underscore the strong red emission, structural tunability, and optical amplification potential of Eu<sup>3+</sup>-doped Ca<sub>2</sub>GdNbO<sub>6</sub> and Ca<sub>2</sub>GdTaO<sub>6</sub> phosphors, confirming their viability as efficient red laser materials and photonic components.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"286 ","pages":"Article 121361"},"PeriodicalIF":3.3,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144298905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}