Aggregation properties of a series of ester-flanked quinolines with D-π-A-A/D architecture were explored. Methoxy-functionalized quinoline derivatives showed strong solvent interactions ranging from toluene to acetonitrile, exhibiting positive solvatochromism. In contrast, halogen-substituted compounds showed little to no interaction. Photophysical studies of all compounds were carried out in a THF/water system, in which compounds without substitution and with the electron-withdrawing group exhibited AIE, and compounds with an electron-donating group resulted in ACQ properties. The observations were supported by single-crystal XRD and powder XRD studies. The fluorescence quantum yield studies suggested the stability of molecules in an aggregated phase. DLS particle size analysis confirmed the formation of stable aggregates. These analyses suggest the potential application of molecules in an aggregated phase.
{"title":"Fluorescence quenching and aggregation-induced emission behaviour of Ester-Flanked Quinolines","authors":"Sambit Kumar Lenka, Anshika Anjali, Murali Ardra, Samuthira Nagarajan","doi":"10.1016/j.jlumin.2025.121661","DOIUrl":"10.1016/j.jlumin.2025.121661","url":null,"abstract":"<div><div>Aggregation properties of a series of ester-flanked quinolines with D-π-A-A/D architecture were explored. Methoxy-functionalized quinoline derivatives showed strong solvent interactions ranging from toluene to acetonitrile, exhibiting positive solvatochromism. In contrast, halogen-substituted compounds showed little to no interaction. Photophysical studies of all compounds were carried out in a THF/water system, in which compounds without substitution and with the electron-withdrawing group exhibited AIE, and compounds with an electron-donating group resulted in ACQ properties. The observations were supported by single-crystal XRD and powder XRD studies. The fluorescence quantum yield studies suggested the stability of molecules in an aggregated phase. DLS particle size analysis confirmed the formation of stable aggregates. These analyses suggest the potential application of molecules in an aggregated phase.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"289 ","pages":"Article 121661"},"PeriodicalIF":3.6,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526059","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}
Pub Date : 2025-11-11DOI: 10.1016/j.jlumin.2025.121660
Jintian Lyu , Mingzi Li , Xiaopin Zhao , Nan Zhou , Jiamin Zhong , Dadong Shen , Kui Du
Nine donor-π-acceptor (D-π-A) phenothiazine isomers bearing different sulfur oxidation states as electron‐donating groups were rationally designed and synthesized. Their fluorescence properties before and after mechanical grinding were systematically studied, including emission spectra, quantum yields, and lifetimes. Among them, compound p-D1A exhibited remarkable Mechanofluorochromic (MFC) with a large emission shift of 107 nm, whereas the other compounds showed shifts of less than 10 nm. Furthermore, density functional theory (DFT) calculations were performed to analyze the frontier molecular orbital energies, donor and acceptor electronic distributions, and optimized molecular geometries. Powder wide‐angle X‐ray diffraction (PXRD) and solvatochromic studies were also conducted, and the single‐crystal structure of p-D1A was obtained to further elucidate its MFC behavior. Combining the experimental and theoretical results, the relationship between MFC behavior, molecular structure, and intramolecular charge transfer (ICT) processes was established. The findings reveal that energy‐level alignment between donor and acceptor plays a more decisive role in determining the ground‐state emission wavelength than structural isomerism within the D-π-A framework. Notably, para‐isomers adopt conformations favorable for the design of efficient MFC‐active molecules. A pronounced ICT process was also found to contribute significantly to the high‐contrast MFC response. Overall, this study demonstrates tunable emission and MFC behaviors achieved by modulating D-π-A structural isomerism and phenothiazine oxidation.
{"title":"Tunable emission behavior and mechanofluorochromism by D-π-A structural isomers and phenothiazine oxidation: a combined experimental and theoretical study","authors":"Jintian Lyu , Mingzi Li , Xiaopin Zhao , Nan Zhou , Jiamin Zhong , Dadong Shen , Kui Du","doi":"10.1016/j.jlumin.2025.121660","DOIUrl":"10.1016/j.jlumin.2025.121660","url":null,"abstract":"<div><div>Nine donor-π-acceptor (D-π-A) phenothiazine isomers bearing different sulfur oxidation states as electron‐donating groups were rationally designed and synthesized. Their fluorescence properties before and after mechanical grinding were systematically studied, including emission spectra, quantum yields, and lifetimes. Among them, compound <em>p</em>-D<sub>1</sub>A exhibited remarkable Mechanofluorochromic (MFC) with a large emission shift of 107 nm, whereas the other compounds showed shifts of less than 10 nm. Furthermore, density functional theory (DFT) calculations were performed to analyze the frontier molecular orbital energies, donor and acceptor electronic distributions, and optimized molecular geometries. Powder wide‐angle X‐ray diffraction (PXRD) and solvatochromic studies were also conducted, and the single‐crystal structure of <em>p</em>-D<sub>1</sub>A was obtained to further elucidate its MFC behavior. Combining the experimental and theoretical results, the relationship between MFC behavior, molecular structure, and intramolecular charge transfer (ICT) processes was established. The findings reveal that energy‐level alignment between donor and acceptor plays a more decisive role in determining the ground‐state emission wavelength than structural isomerism within the D-π-A framework. Notably, para‐isomers adopt conformations favorable for the design of efficient MFC‐active molecules. A pronounced ICT process was also found to contribute significantly to the high‐contrast MFC response. Overall, this study demonstrates tunable emission and MFC behaviors achieved by modulating D-π-A structural isomerism and phenothiazine oxidation.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"289 ","pages":"Article 121660"},"PeriodicalIF":3.6,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576645","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}
Pub Date : 2025-11-11DOI: 10.1016/j.jlumin.2025.121651
Shirun Yan
Luminescence thermal quenching (TQ) remains a critical challenge for the utilization of phosphors in high-temperature environments. Elucidating the TQ behavior and its underlying mechanisms for specific phosphors is vital for advancing both fundamental understanding and technological innovations. Traditionally, researchers have primarily relied on temperature-dependent fluorescence intensity measurements to evaluate TQ owing to their experimental simplicity. Variations in emission intensity are typically modeled using Arrhenius-type equations to extract activation energies and quenching temperatures. This paper examines the suitability of using temperature-dependent emission intensity as a metric for characterizing luminescence TQ in solid samples by analyzing existing literature data from two perspectives: (1) Can temperature-dependent emission intensity variations be consistently replicated across nominally identical phosphors under controlled experimental conditions? (2) Does the temperature-dependent emission intensity trend systematically reflect changes in quantum yield (QY) for a particular phosphor. The two-fold analysis reveals that temperature-dependent fluorescence emission intensity is an inadequate metric for assessing luminescence TQ of solid phosphors. Its limitations stem from sensitivity to extrinsic factors, such as spectral shifts, or instrumental drift at elevated temperatures, that obscure intrinsic QY variations. To achieve robust characterization of TQ in solid phosphors, it is recommended to measure the QY of the phosphor using an integrating sphere setup across temperature gradients.
{"title":"Is temperature-dependent emission intensity a reliable metric for characterizing luminescence thermal quenching in solid-state phosphors?","authors":"Shirun Yan","doi":"10.1016/j.jlumin.2025.121651","DOIUrl":"10.1016/j.jlumin.2025.121651","url":null,"abstract":"<div><div>Luminescence thermal quenching (TQ) remains a critical challenge for the utilization of phosphors in high-temperature environments. Elucidating the TQ behavior and its underlying mechanisms for specific phosphors is vital for advancing both fundamental understanding and technological innovations. Traditionally, researchers have primarily relied on temperature-dependent fluorescence intensity measurements to evaluate TQ owing to their experimental simplicity. Variations in emission intensity are typically modeled using Arrhenius-type equations to extract activation energies and quenching temperatures. This paper examines the suitability of using temperature-dependent emission intensity as a metric for characterizing luminescence TQ in solid samples by analyzing existing literature data from two perspectives: (1) Can temperature-dependent emission intensity variations be consistently replicated across nominally identical phosphors under controlled experimental conditions? (2) Does the temperature-dependent emission intensity trend systematically reflect changes in quantum yield (QY) for a particular phosphor. The two-fold analysis reveals that temperature-dependent fluorescence emission intensity is an inadequate metric for assessing luminescence TQ of solid phosphors. Its limitations stem from sensitivity to extrinsic factors, such as spectral shifts, or instrumental drift at elevated temperatures, that obscure intrinsic QY variations. To achieve robust characterization of TQ in solid phosphors, it is recommended to measure the QY of the phosphor using an integrating sphere setup across temperature gradients.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"289 ","pages":"Article 121651"},"PeriodicalIF":3.6,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145525990","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}
Pub Date : 2025-11-10DOI: 10.1016/j.jlumin.2025.121656
Shaozhen Lv , Shaobo Yao , Fujian He , Zhuohong Feng
Optical thermometry based on fluorescence intensity ratio(FIR) technique has been under researched for past few decades. However, the optical temperature sensing materials with high sensitivity and wide temperature range still remain a challenge. In this paper, triple-doped Yb3+/Er3+/Ho3+:CaYAlO4 phosphor has been studied for temperature sensing for the first time. Under 980 nm excitation, four characteristic emission bands were observed which attribute to the transitions of Er3+: 2H11/2 → 4I15/2 (528 nm), Er3+:4S3/2 → 4I15/2 and Ho3+:5S2,5F4 →5I8 (550 nm), Er3+:4F9/2 → 4I15/2 and Ho3+:5F5 →5I8 (665 nm) and Ho3+:5S2,5F4 →5I7 (757 nm) respectively. The temperature sensing behaviors of the phosphors were investigated based on six FIRs pairs (FIR528/550, FIR528/665, FIR528/757, FIR550/757, FIR665/550 and FIR665/757) over a wide temperature range 163K–700K. The maximum absolute sensitivities of FIR528/757, FIR550/757 and FIR665/757 are 23.37 10−3 K−1,13.39 10−3 K−1 and 150.35 10−3 K−1 at 583K, 163K and 499K respectively. Results suggest that Yb3+/Er3+: CaYAlO4 phosphor is a promising temperature measuring material with advanced optical sensing capabilities over a wide temperature range.
{"title":"High temperature sensing performance of Yb3+,Er3+,Ho3+:CaYAlO4 phosphor in a wide range","authors":"Shaozhen Lv , Shaobo Yao , Fujian He , Zhuohong Feng","doi":"10.1016/j.jlumin.2025.121656","DOIUrl":"10.1016/j.jlumin.2025.121656","url":null,"abstract":"<div><div>Optical thermometry based on fluorescence intensity ratio(FIR) technique has been under researched for past few decades. However, the optical temperature sensing materials with high sensitivity and wide temperature range still remain a challenge. In this paper, triple-doped Yb<sup>3+</sup>/Er<sup>3+</sup>/Ho<sup>3+</sup>:CaYAlO<sub>4</sub> phosphor has been studied for temperature sensing for the first time. Under 980 nm excitation, four characteristic emission bands were observed which attribute to the transitions of Er<sup>3+</sup>: <sup>2</sup>H<sub>11/2</sub> → <sup>4</sup>I<sub>15/2</sub> (528 nm), Er<sup>3+</sup>:<sup>4</sup>S<sub>3/2</sub> → <sup>4</sup>I<sub>15/2</sub> and Ho<sup>3+</sup>:<sup>5</sup>S<sub>2</sub>,<sup>5</sup>F<sub>4</sub> →<sup>5</sup>I<sub>8</sub> (550 nm), Er<sup>3+</sup>:<sup>4</sup>F<sub>9/2</sub> → <sup>4</sup>I<sub>15/2</sub> and Ho<sup>3+</sup>:<sup>5</sup>F<sub>5</sub> →<sup>5</sup>I<sub>8</sub> (665 nm) and Ho<sup>3+</sup>:<sup>5</sup>S<sub>2</sub>,<sup>5</sup>F<sub>4</sub> →<sup>5</sup>I<sub>7</sub> (757 nm) respectively. The temperature sensing behaviors of the phosphors were investigated based on six FIRs pairs (FIR<sub>528/550</sub>, FIR<sub>528/665</sub>, FIR<sub>528/757,</sub> FIR<sub>550/757</sub>, FIR<sub>665/550</sub> and FIR<sub>665/757</sub>) over a wide temperature range 163K–700K. The maximum absolute sensitivities <span><math><mrow><msub><mi>S</mi><mi>a</mi></msub></mrow></math></span> of FIR<sub>528/757,</sub> FIR<sub>550/757</sub> and FIR<sub>665/757</sub> are 23.37 <span><math><mrow><mo>×</mo></mrow></math></span> 10<sup>−3</sup> K<sup>−1</sup>,13.39 <span><math><mrow><mo>×</mo></mrow></math></span> 10<sup>−3</sup> K<sup>−1</sup> and 150.35 <span><math><mrow><mo>×</mo></mrow></math></span> 10<sup>−3</sup> K<sup>−1</sup> at 583K, 163K and 499K respectively. Results suggest that Yb<sup>3+</sup>/Er<sup>3+</sup>: CaYAlO<sub>4</sub> phosphor is a promising temperature measuring material with advanced optical sensing capabilities over a wide temperature range.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"289 ","pages":"Article 121656"},"PeriodicalIF":3.6,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576665","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}
Pub Date : 2025-11-10DOI: 10.1016/j.jlumin.2025.121658
Liu He , Jianfei Jin , Yun Si , Chenxi Luo
Intracellular pH dynamics significantly influences a wide array of cellular processes, including cell proliferation, apoptosis and endocytosis and enzyme activity. To monitor real-time change of intracellular pH values, we developed a novel ratiometric pH-responsive fluorescent probe, TPSP, based on Förster resonance energy transfer (FRET) and intramolecular charge transfer (ICT) mechanism. Extracellular evaluations demonstrated a good linear correlation (R2 = 0.9935) between the fluorescence ratio of TPSP and pH values ranging from 4.0 to 5.0 (pKa = 4.64). Given the remarkable acidic microenvironment (pH 3.8–4.7) in tumor cell lysosomes, we performed further biological experiments, which validated precise localization of lysosomes in colorectal cancer (CRC) cells and specific in vivo imaging of CRC tumors in mouse models. These findings preliminarily suggest that TPSP could serves as a promising molecular tool for pH dynamics monitoring, lysosomal function assessment and intraoperative navigation.
{"title":"A novel ratiometric pH-responsive fluorescent probe based on FRET-ICT mechanism for lysosome targeting and in vivo imaging of colorectal cancer","authors":"Liu He , Jianfei Jin , Yun Si , Chenxi Luo","doi":"10.1016/j.jlumin.2025.121658","DOIUrl":"10.1016/j.jlumin.2025.121658","url":null,"abstract":"<div><div>Intracellular pH dynamics significantly influences a wide array of cellular processes, including cell proliferation, apoptosis and endocytosis and enzyme activity. To monitor real-time change of intracellular pH values, we developed a novel ratiometric pH-responsive fluorescent probe, TPSP, based on Förster resonance energy transfer (FRET) and intramolecular charge transfer (ICT) mechanism. Extracellular evaluations demonstrated a good linear correlation (R<sup>2</sup> = 0.9935) between the fluorescence ratio of TPSP and pH values ranging from 4.0 to 5.0 (pK<sub>a</sub> = 4.64). Given the remarkable acidic microenvironment (pH 3.8–4.7) in tumor cell lysosomes, we performed further biological experiments, which validated precise localization of lysosomes in colorectal cancer (CRC) cells and specific in vivo imaging of CRC tumors in mouse models. These findings preliminarily suggest that TPSP could serves as a promising molecular tool for pH dynamics monitoring, lysosomal function assessment and intraoperative navigation.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"289 ","pages":"Article 121658"},"PeriodicalIF":3.6,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145525987","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}
Pub Date : 2025-11-10DOI: 10.1016/j.jlumin.2025.121657
Hao Zhang, Bo Zhang, Ziqiang Yu, Junyou Li, Yibo Zhang, Qi Han
A series of KxNa1-xLuF4: Yb/Er/Tm phosphors are prepared by a hydrothermal method. The up-conversion luminescence and temperature sensing characteristics of phosphors doped with different K ion concentration under 980 nm laser excitation are studied. With the change of concentration of K ion, the red, green and blue emissions intensities of phosphors are obviously enhanced and the proportion of each emission peak intensity also are affected. The influence of K ion concentration on the up-conversion luminescence color of phosphors are studied at different excitation power. The maximum temperature sensitivity derived from the thermal and non-thermal coupled levels is explored in the temperature range of 303 K–623 K via the fluorescence intensity ratio technique. The sensitivities vary significantly under different K ion incorporation concentration. These results validate the superior up-conversion characteristics and temperature sensing performance of KxNa1-xLuF4: Yb/Er/Tm phosphors, indicating that this phosphors has great research potential.
采用水热法制备了KxNa1-xLuF4: Yb/Er/Tm系列荧光粉。研究了掺杂不同K离子浓度的荧光粉在980 nm激光激发下的上转换发光和感温特性。随着K离子浓度的变化，荧光粉的红、绿、蓝发射强度明显增强，各发射峰强度所占比例也受到影响。研究了不同激发功率下K离子浓度对荧光粉上转换发光颜色的影响。通过荧光强度比技术，在303 K - 623 K的温度范围内探索了热耦合和非热耦合能级的最大温度灵敏度。不同钾离子掺入浓度下，灵敏度差异显著。这些结果验证了KxNa1-xLuF4: Yb/Er/Tm荧光粉优越的上转换特性和温度传感性能，表明该荧光粉具有很大的研究潜力。
{"title":"Superior luminescence efficiency and temperature sensing behavior of NaLuF4 phosphor based on K ion incorporation","authors":"Hao Zhang, Bo Zhang, Ziqiang Yu, Junyou Li, Yibo Zhang, Qi Han","doi":"10.1016/j.jlumin.2025.121657","DOIUrl":"10.1016/j.jlumin.2025.121657","url":null,"abstract":"<div><div>A series of K<sub>x</sub>Na<sub>1-x</sub>LuF<sub>4</sub>: Yb/Er/Tm phosphors are prepared by a hydrothermal method. The up-conversion luminescence and temperature sensing characteristics of phosphors doped with different K ion concentration under 980 nm laser excitation are studied. With the change of concentration of K ion, the red, green and blue emissions intensities of phosphors are obviously enhanced and the proportion of each emission peak intensity also are affected. The influence of K ion concentration on the up-conversion luminescence color of phosphors are studied at different excitation power. The maximum temperature sensitivity derived from the thermal and non-thermal coupled levels is explored in the temperature range of 303 K–623 K via the fluorescence intensity ratio technique. The sensitivities vary significantly under different K ion incorporation concentration. These results validate the superior up-conversion characteristics and temperature sensing performance of K<sub>x</sub>Na<sub>1-x</sub>LuF<sub>4</sub>: Yb/Er/Tm phosphors, indicating that this phosphors has great research potential.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"289 ","pages":"Article 121657"},"PeriodicalIF":3.6,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526001","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}
Pub Date : 2025-11-10DOI: 10.1016/j.jlumin.2025.121659
Hua Fang, Jialun Zhang
4-dimethylamino-2′-hydroxychalcone (HCA) exhibits excited state intramolecular proton transfer (ESIPT) properties and strong fluorescence in the solid state, making its highly attractive for application in organic optoelectronics. In order to investigate the effect of nitrogen atom substitution on the fluorescent properties and ESIPT process of HCA compound, three HCA derivatives (HCA-1, HCA-2 and HCA-3) were designed by replacing the -CH groups at different positions on the benzene ring of HCA with nitrogen atoms. Using density functional theory (DFT) and time-dependent DFT (TD-DFT) methods, the ESIPT processes, fluorescent properties and aromaticity of HCA and its derivatives were studied in detail. The calculation level of B3LYP/6-311+G(d,p) has been proven to be reliable since the absorption/fluorescence wavelength of HCA obtained in the experiment has been reproduced. The results showed that nitrogen substitution led to a blue-shift in the maximum absorption peak, a significant red-shift in the maximum fluorescence peak of tautomer, and an obvious increase in the Stokes shift generated by its tautomer. Nitrogen substitution also reduces the ESIPT barrier and aromaticity. Di-nitrogen substitution is more effective than mono-nitrogen substitution.
{"title":"Ring aromaticity and ESIPT behavior of 4-dimethylamino-2′-hydroxychalcone based on nitrogen substitution: A TD-DFT insight","authors":"Hua Fang, Jialun Zhang","doi":"10.1016/j.jlumin.2025.121659","DOIUrl":"10.1016/j.jlumin.2025.121659","url":null,"abstract":"<div><div>4-dimethylamino-2′-hydroxychalcone (HCA) exhibits excited state intramolecular proton transfer (ESIPT) properties and strong fluorescence in the solid state, making its highly attractive for application in organic optoelectronics. In order to investigate the effect of nitrogen atom substitution on the fluorescent properties and ESIPT process of HCA compound, three HCA derivatives (HCA-1, HCA-2 and HCA-3) were designed by replacing the -CH groups at different positions on the benzene ring of HCA with nitrogen atoms. Using density functional theory (DFT) and time-dependent DFT (TD-DFT) methods, the ESIPT processes, fluorescent properties and aromaticity of HCA and its derivatives were studied in detail. The calculation level of B3LYP/6-311+G(d,p) has been proven to be reliable since the absorption/fluorescence wavelength of HCA obtained in the experiment has been reproduced. The results showed that nitrogen substitution led to a blue-shift in the maximum absorption peak, a significant red-shift in the maximum fluorescence peak of tautomer, and an obvious increase in the Stokes shift generated by its tautomer. Nitrogen substitution also reduces the ESIPT barrier and aromaticity. Di-nitrogen substitution is more effective than mono-nitrogen substitution.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"289 ","pages":"Article 121659"},"PeriodicalIF":3.6,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526000","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}
Pub Date : 2025-11-07DOI: 10.1016/j.jlumin.2025.121650
Peng Wang , Xuanchu Liu , Jinhua Wang , Jian Kang , Yang Li , Wieslaw Strek , Robert Tomala , Mariusz Stefanski , Hongbin Cai , Hao Chen , Le Zhang
In high-power laser-excited solid-state lighting, ceramic phosphors face severe challenges in thermal management and light extraction. This study proposed a hemispherical YAG:Ce/Al2O3 composite structure to address these issues through optical path regulation. The design employed highly thermally conductive Al2O3 (15.2 W m−1 K−1) to encapsulate a curved YAG:Ce phosphor layer, integrating Fresnel lens-based light field control with Al2O3 heat conduction to achieve synergistic optical-thermal management. By utilizing multipath reflection to enhance the utilization efficiency of unabsorbed blue light and trapped fluorescence, the structure improved luminous efficiency by 15 % compared to planar ceramics. Under 40.23 W/mm2 blue laser excitation, the operating temperature remained as low as 111.1 °C (significantly lower than conventional systems (300–400 °C). Based on these results, a theoretical framework for hemispherical continuous Fresnel lens-based optical regulation under high-power-density excitation was further proposed. This work not only provides a novel “optical-thermal coordination” strategy for managing photothermal issues in ceramic phosphors but also offers valuable guidance for the design of high-performance phosphor materials for laser lighting applications.
在高功率激光激发固态照明中，陶瓷荧光粉在热管理和光提取方面面临着严峻的挑战。本研究提出了一个半球形YAG:Ce/Al2O3复合结构，通过光路调节来解决这些问题。该设计采用高导热Al2O3 （15.2 W m−1 K−1）封装弯曲的YAG:Ce荧光粉层，将基于菲涅耳透镜的光场控制与Al2O3热传导相结合，实现协同光热管理。通过利用多径反射提高未吸收蓝光和捕获荧光的利用效率，该结构比平面陶瓷的发光效率提高了15%。在40.23 W/mm2蓝色激光激发下，工作温度保持在111.1°C（显著低于常规系统（300-400°C））。在此基础上，进一步提出了高功率密度激励下半球面连续菲涅耳透镜光学调节的理论框架。这项工作不仅为陶瓷荧光粉的光热问题提供了一种新的“光热协调”策略，而且为激光照明应用的高性能荧光粉材料的设计提供了有价值的指导。
{"title":"Optical field modulation and its mechanism of YAG:Ce/Al2O3 composite phosphor ceramic in high-power laser lighting","authors":"Peng Wang , Xuanchu Liu , Jinhua Wang , Jian Kang , Yang Li , Wieslaw Strek , Robert Tomala , Mariusz Stefanski , Hongbin Cai , Hao Chen , Le Zhang","doi":"10.1016/j.jlumin.2025.121650","DOIUrl":"10.1016/j.jlumin.2025.121650","url":null,"abstract":"<div><div>In high-power laser-excited solid-state lighting, ceramic phosphors face severe challenges in thermal management and light extraction. This study proposed a hemispherical YAG:Ce/Al<sub>2</sub>O<sub>3</sub> composite structure to address these issues through optical path regulation. The design employed highly thermally conductive Al<sub>2</sub>O<sub>3</sub> (15.2 W m<sup>−1</sup> K<sup>−1</sup>) to encapsulate a curved YAG:Ce phosphor layer, integrating Fresnel lens-based light field control with Al<sub>2</sub>O<sub>3</sub> heat conduction to achieve synergistic optical-thermal management. By utilizing multipath reflection to enhance the utilization efficiency of unabsorbed blue light and trapped fluorescence, the structure improved luminous efficiency by 15 % compared to planar ceramics. Under 40.23 W/mm<sup>2</sup> blue laser excitation, the operating temperature remained as low as 111.1 °C (significantly lower than conventional systems (300–400 °C). Based on these results, a theoretical framework for hemispherical continuous Fresnel lens-based optical regulation under high-power-density excitation was further proposed. This work not only provides a novel “optical-thermal coordination” strategy for managing photothermal issues in ceramic phosphors but also offers valuable guidance for the design of high-performance phosphor materials for laser lighting applications.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"289 ","pages":"Article 121650"},"PeriodicalIF":3.6,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145525988","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}
Pub Date : 2025-11-07DOI: 10.1016/j.jlumin.2025.121653
N. Miniajluk-Gaweł , B. Bondzior , A. Chudzyńska , P.J. Dereń
Spherical amorphous LaAlO3 doped with Tb3+ ions (∼1.0 mm) were produced by aerodynamic levitation from LaAlO3:Tb3+ perovskite powders, which had been prepared by either solid-state reaction or co-precipitation. The impact of these routes on the spectroscopic behavior of the resulting amorphous LaAlO3:Tb3+ was systematically examined. Structural characterization (XRD, SEM, EDS) and spectroscopic analysis (emission/excitation spectra, decay curves) were carried out on both the powders and the amorphous beads. Results show that the synthesis route strongly influences material properties: co-precipitation introduces lattice defects that promote Tb3+ oxidation to Tb4+, which in turn blocks energy transfer between Tb3+ ions. This identifies a key drawback of the co-precipitation approach.
{"title":"Levitation synthesis of luminescent glasses based on LaAlO3:Tb3+ with modified spectroscopic properties","authors":"N. Miniajluk-Gaweł , B. Bondzior , A. Chudzyńska , P.J. Dereń","doi":"10.1016/j.jlumin.2025.121653","DOIUrl":"10.1016/j.jlumin.2025.121653","url":null,"abstract":"<div><div>Spherical amorphous LaAlO<sub>3</sub> doped with Tb<sup>3+</sup> ions (∼1.0 mm) were produced by aerodynamic levitation from LaAlO<sub>3</sub>:Tb<sup>3+</sup> perovskite powders, which had been prepared by either solid-state reaction or co-precipitation. The impact of these routes on the spectroscopic behavior of the resulting amorphous LaAlO<sub>3</sub>:Tb<sup>3+</sup> was systematically examined. Structural characterization (XRD, SEM, EDS) and spectroscopic analysis (emission/excitation spectra, decay curves) were carried out on both the powders and the amorphous beads. Results show that the synthesis route strongly influences material properties: co-precipitation introduces lattice defects that promote Tb<sup>3+</sup> oxidation to Tb<sup>4+</sup>, which in turn blocks energy transfer between Tb<sup>3+</sup> ions. This identifies a key drawback of the co-precipitation approach.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"289 ","pages":"Article 121653"},"PeriodicalIF":3.6,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145525986","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}
Pub Date : 2025-11-07DOI: 10.1016/j.jlumin.2025.121654
Guofeng Zhang , Rui Hu , Dasheng Zheng , Yan Zhao , Zhiguo Song , Yongjin Li
Currently, the lack of efficient red/orange-light phosphor interferes with the performance improvement of white light emitting diodes (WLEDs) because of notably low color rendering index. Multicolor phosphors are considered to be able to solve the aforesaid shortcoming of existing WLEDs when assembled with ultraviolet or blue LED chips, thus the development of dual-emission phosphors has been a popular research field. Here, we synthesized a series of Li2SrTa2O7:Pr3+/Gd3+ phosphor materials, and investigated their crystal structure and luminescent properties, including X-ray diffraction, diffuse reflectance spectra, photoluminescence, long-persistent luminescence. Results reveal that Li2SrTa2O7:Pr3+/Gd3+ phosphors exhibit two dominant photoluminescence emission peaks at 495 nm and 620 nm respectively upon 295 nm excitation, showing bright yellow-green to the naked eyes, while their afterglow spectra show orange emission peaking at 620 nm. Their light color of photoluminescence emission can change from yellow-green to red with increasing temperature (300–490 K) along with minor thermal quenching. Moreover, an excellent orange LED lamp with the CIE chromaticity coordinates of (0.3986, 0.3832), the CCT of 3591 K is obtained by fabricating Li1.99SrTa2O7:4 %Pr3+/4 %Gd3+ phosphor with a 310 nm LED chip. This research provides a practical foundation to understand and regulate the luminescent performance, and proposes a new strategy to realize warm light illumination of pc-LED devices.
{"title":"Color-tunable Pr3+-activated dual-emission tantalate materials for warm lighting LEDs","authors":"Guofeng Zhang , Rui Hu , Dasheng Zheng , Yan Zhao , Zhiguo Song , Yongjin Li","doi":"10.1016/j.jlumin.2025.121654","DOIUrl":"10.1016/j.jlumin.2025.121654","url":null,"abstract":"<div><div>Currently, the lack of efficient red/orange-light phosphor interferes with the performance improvement of white light emitting diodes (WLEDs) because of notably low color rendering index. Multicolor phosphors are considered to be able to solve the aforesaid shortcoming of existing WLEDs when assembled with ultraviolet or blue LED chips, thus the development of dual-emission phosphors has been a popular research field. Here, we synthesized a series of Li<sub>2</sub>SrTa<sub>2</sub>O<sub>7</sub>:Pr<sup>3+</sup>/Gd<sup>3+</sup> phosphor materials, and investigated their crystal structure and luminescent properties, including X-ray diffraction, diffuse reflectance spectra, photoluminescence, long-persistent luminescence. Results reveal that Li<sub>2</sub>SrTa<sub>2</sub>O<sub>7</sub>:Pr<sup>3+</sup>/Gd<sup>3+</sup> phosphors exhibit two dominant photoluminescence emission peaks at 495 nm and 620 nm respectively upon 295 nm excitation, showing bright yellow-green to the naked eyes, while their afterglow spectra show orange emission peaking at 620 nm. Their light color of photoluminescence emission can change from yellow-green to red with increasing temperature (300–490 K) along with minor thermal quenching. Moreover, an excellent orange LED lamp with the CIE chromaticity coordinates of (0.3986, 0.3832), the CCT of 3591 K is obtained by fabricating Li<sub>1.99</sub>SrTa<sub>2</sub>O<sub>7</sub>:4 %Pr<sup>3+</sup>/4 %Gd<sup>3+</sup> phosphor with a 310 nm LED chip. This research provides a practical foundation to understand and regulate the luminescent performance, and proposes a new strategy to realize warm light illumination of pc-LED devices.</div></div>","PeriodicalId":16159,"journal":{"name":"Journal of Luminescence","volume":"289 ","pages":"Article 121654"},"PeriodicalIF":3.6,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145525991","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}
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