In lanthanide(Ln)complexes,the oversight of f-electrons and inner-shell relativistic interactions has constituted a critical gap,limiting a nuanced understanding and modulation of their luminescent properties.Addressi...In lanthanide(Ln)complexes,the oversight of f-electrons and inner-shell relativistic interactions has constituted a critical gap,limiting a nuanced understanding and modulation of their luminescent properties.Addressing this issue,our study introduces a pioneering series of Ln-based metal-organic frameworks(Ln-MOFs),designated as Ln-TCPP,utilizing tetraphenylpyrazinederived ligand and Ln^(3+)ions(Ln=Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb and Lu)to modulate luminescence through advanced synthesis and theoretical analysis.We particularly emphasize the enhancement of Eu^(3+)luminescence in Ln-TCPP,where incorporating Ag^(+)ions to replace[(CH_(3))_(2)NH_(2)]^(+)within the Ln-MOFs plays a pivotal role.Theoretically,by employing timedependent density functional theory(TD-DFT)with full-electron relativistic effects,we demonstrate that Ag^(+)ions induce a splitting in the energy levels of Eu^(3+).This splitting effectively reduces the rate of non-radiative transitions,significantly amplifying Eu^(3+)emission intensity.Our findings not only fill a long-standing void in understanding the all-electron relativistic interaction between f-electrons in Ln-MOFs luminescence but also establish a new strategy for controlling and optimizing the luminescent efficacy of these materials for potential applications.展开更多
Based on the combination of Racah＇s group-theoretical consideration with Slater＇s wavefunction, a 91 ×91 complete energy matrix is established in tetragonal ligand field D2d for Pr3＋ ion. Thus, the Stark energ...Based on the combination of Racah＇s group-theoretical consideration with Slater＇s wavefunction, a 91 ×91 complete energy matrix is established in tetragonal ligand field D2d for Pr3＋ ion. Thus, the Stark energy-levels of Pr3＋ ions doped separately in LiYF4 and LiBiF4 crystals are calculated, and our calculations imply that the complete energy matrix method can be used as an effective tool to calculate the energy-levels of the systems doped by rare earth ions. Besides, the influence of Pr3＋ on energy-level splitting is investigated, and the similarities and the differences between the two doped crystals are demonstrated in detail by comparing their several pairs of curves and crystal field strength quantities. We see that the energy splitting patterns are similar and the crystal field interaction of LiYF4：Pr3＋ is stronger than that of LiBiF4：Pr3＋.展开更多
The electrochemical behaviors of battery chemistry,especially the operating voltage,are greatly affected by the complex electrode/electrolyte interface,but the corresponding basis understanding is still largely unclea...The electrochemical behaviors of battery chemistry,especially the operating voltage,are greatly affected by the complex electrode/electrolyte interface,but the corresponding basis understanding is still largely unclear.Herein,the concept of regulating electrode potential by interface thermodynamics is proposed,which guides the improvement of the energy density of Zn-MnO_(2) battery.A cationic electrolyte strategy is adopted to adjust the charge density of electrical double layer,as well as entropy change caused by desolvation,thus,achieving an output voltage of 1.6 V(vs.Zn^(2+)/Zn)and a capacity of 400 mAh g^(-1).The detailed energy storage behaviors are also analyzed in terms of crystal field and energy level splitting.Furthermore,the electrolyte optimization benefits the efficient operation of Zn-MnO_(2) battery by enabling a high energy density of 532 Wh kg^(-1) based on the mass of cathode and a long cyclic life of more than 500 cycles.This work provides a path for designing high-energy-density aqueous battery via electrolyte strategy,which is expected to be extended to other battery systems.展开更多
Optical waveguide amplifiers are essential devices in integrated optical systems,with their gain bandwidths directly influencing the operating wavelengths of optical circuits.Previous Er^(3+)-doped polymer optical wav...Optical waveguide amplifiers are essential devices in integrated optical systems,with their gain bandwidths directly influencing the operating wavelengths of optical circuits.Previous Er^(3+)-doped polymer optical waveguide amplifiers have been limited to amplifying signals within the C-band.To achieve broadband polymer optical waveguide amplification,we propose the use of nanocrystals with low crystal field symmetry to extend the working bandwidth.Our approach utilizes LiYF_(4):Yb,Er nanoparticles embedded in poly(methyl methacrylate)as the gain medium,enabling signal amplification from most of the S-band to the whole(C+L)band.The low crystal field symmetry of the LiYF_(4)host significantly splits the^(4)I_(13/2)and^(4)I_(15/2)levels of Er^(3+)ions owing to the crystal field effect,facilitating broadband down-conversion luminescence under 980-nm excitation.Furthermore,a fluorescence kinetic analysis confirms that the broadband luminescence of Er^(3+)arises from significant energy-level splitting caused by the crystal field effect.Under 980-nm excitation,the amplifiers exhibited relative gains of approximately 12.6 dB at 1535 nm,7.4 dB at 1480 nm,and 3.7 dB at 1610 nm.The Er^(3+)-doped broadband polymer optical waveguide amplifier was successfully prepared.展开更多
基金supported by the National Natural Science Foundation of China (22221001,22131007,22401119)the Science and Technology Major Plan of Gansu Province (23ZDGA012,24JRRA435)+1 种基金the 111 Project (B20027)the Fundamental Research Funds for the Central Universities (lzujbky-2024-jdzx13)。
文摘In lanthanide(Ln)complexes,the oversight of f-electrons and inner-shell relativistic interactions has constituted a critical gap,limiting a nuanced understanding and modulation of their luminescent properties.Addressing this issue,our study introduces a pioneering series of Ln-based metal-organic frameworks(Ln-MOFs),designated as Ln-TCPP,utilizing tetraphenylpyrazinederived ligand and Ln^(3+)ions(Ln=Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb and Lu)to modulate luminescence through advanced synthesis and theoretical analysis.We particularly emphasize the enhancement of Eu^(3+)luminescence in Ln-TCPP,where incorporating Ag^(+)ions to replace[(CH_(3))_(2)NH_(2)]^(+)within the Ln-MOFs plays a pivotal role.Theoretically,by employing timedependent density functional theory(TD-DFT)with full-electron relativistic effects,we demonstrate that Ag^(+)ions induce a splitting in the energy levels of Eu^(3+).This splitting effectively reduces the rate of non-radiative transitions,significantly amplifying Eu^(3+)emission intensity.Our findings not only fill a long-standing void in understanding the all-electron relativistic interaction between f-electrons in Ln-MOFs luminescence but also establish a new strategy for controlling and optimizing the luminescent efficacy of these materials for potential applications.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.10774103 and 10974138)
文摘Based on the combination of Racah＇s group-theoretical consideration with Slater＇s wavefunction, a 91 ×91 complete energy matrix is established in tetragonal ligand field D2d for Pr3＋ ion. Thus, the Stark energy-levels of Pr3＋ ions doped separately in LiYF4 and LiBiF4 crystals are calculated, and our calculations imply that the complete energy matrix method can be used as an effective tool to calculate the energy-levels of the systems doped by rare earth ions. Besides, the influence of Pr3＋ on energy-level splitting is investigated, and the similarities and the differences between the two doped crystals are demonstrated in detail by comparing their several pairs of curves and crystal field strength quantities. We see that the energy splitting patterns are similar and the crystal field interaction of LiYF4：Pr3＋ is stronger than that of LiBiF4：Pr3＋.
基金supported by the National Natural Science Foundation of China(52072411,51932011)the Natural Science Foundation of Hunan Province(2021JJ20060)the Fundamental Research Funds for the Central Universities of Central South University(2021zzts0093)。
文摘The electrochemical behaviors of battery chemistry,especially the operating voltage,are greatly affected by the complex electrode/electrolyte interface,but the corresponding basis understanding is still largely unclear.Herein,the concept of regulating electrode potential by interface thermodynamics is proposed,which guides the improvement of the energy density of Zn-MnO_(2) battery.A cationic electrolyte strategy is adopted to adjust the charge density of electrical double layer,as well as entropy change caused by desolvation,thus,achieving an output voltage of 1.6 V(vs.Zn^(2+)/Zn)and a capacity of 400 mAh g^(-1).The detailed energy storage behaviors are also analyzed in terms of crystal field and energy level splitting.Furthermore,the electrolyte optimization benefits the efficient operation of Zn-MnO_(2) battery by enabling a high energy density of 532 Wh kg^(-1) based on the mass of cathode and a long cyclic life of more than 500 cycles.This work provides a path for designing high-energy-density aqueous battery via electrolyte strategy,which is expected to be extended to other battery systems.
基金supported by the National Key Research and Development Program of China(2021YFB2800502)the National Natural Science Foundation of China(U22A2085 and 12174150)。
文摘Optical waveguide amplifiers are essential devices in integrated optical systems,with their gain bandwidths directly influencing the operating wavelengths of optical circuits.Previous Er^(3+)-doped polymer optical waveguide amplifiers have been limited to amplifying signals within the C-band.To achieve broadband polymer optical waveguide amplification,we propose the use of nanocrystals with low crystal field symmetry to extend the working bandwidth.Our approach utilizes LiYF_(4):Yb,Er nanoparticles embedded in poly(methyl methacrylate)as the gain medium,enabling signal amplification from most of the S-band to the whole(C+L)band.The low crystal field symmetry of the LiYF_(4)host significantly splits the^(4)I_(13/2)and^(4)I_(15/2)levels of Er^(3+)ions owing to the crystal field effect,facilitating broadband down-conversion luminescence under 980-nm excitation.Furthermore,a fluorescence kinetic analysis confirms that the broadband luminescence of Er^(3+)arises from significant energy-level splitting caused by the crystal field effect.Under 980-nm excitation,the amplifiers exhibited relative gains of approximately 12.6 dB at 1535 nm,7.4 dB at 1480 nm,and 3.7 dB at 1610 nm.The Er^(3+)-doped broadband polymer optical waveguide amplifier was successfully prepared.
