- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Excitonic Luminescence Engineering in Tervalent Europium Doped Cesium Lead Halide Perovskite Nanocrystals and Their Temperature-Dependent Energy Transfer Emission Properties
摘要： Cesium lead halide (CsPbX3 (X=Cl, Br, I)) perovskite nanocrystals (NCs) have revealed brilliant prospect in lighting, display and lasing fields owing to their excellent photoluminescence properties. To dope rare earth ions into halide perovskite, CsPbX3 (X=Cl, Br, I) NCs hosts not only inherit the excellent narrow linewidth excitonic properties but also yield unique photoluminescence emission. Herein, engineering of such excitonic luminescence is achieved in Eu3+ doped CsPbCl3-xBrx (x=0, 1, 1.5, 2, 3) solid solution NCs for the first time. The single doped-NCs present wide color gamut emission covering whole visible spectrum. Blue to green range (400-520 nm) emission is taken on by tunable excitonic photoluminescence of CsPbX3 NCs. Besides, there is a broad red spectra (590-700 nm) originating from emission of the tervalent europium ions in NCs. Meanwhile, a noticeable spin-polarized 5D0→7F1-6 emission of Eu3+ ions is acquired owing to energy transfer from excitons to dopants. Moreover, the energy transfer is temperature-dependent which originating from the increase of nonradiative transition probability, leading to decrease for the NCs hosts’ PL intensity, but increase for the PL intensity of dopants.
关键词： Eu3+ doped,excitonic luminescence,Cesium lead halide,energy transfer,perovskite nanocrystals
更新于2025-09-10 09:29:36
-
Assessment of Gate Width Size on Lifetime-Based F?rster Resonance Energy Transfer Parameter Estimation
摘要： F?rster Resonance Energy Transfer (FRET) enables the observation of interactions at the nanoscale level through the use of fluorescence optical imaging techniques. In FRET, fluorescence lifetime imaging can be used to quantify the fluorescence lifetime changes of the donor molecule, which are associated with proximity between acceptor and donor molecules. Among the FRET parameters derived from fluorescence lifetime imaging, the percentage of donor that interacts with the acceptor (in proximity) can be estimated via model-based fitting. However, estimation of the lifetime parameters can be affected by the acquisition parameters such as the temporal characteristics of the imaging system. Herein, we investigate the effect of various gate widths on the accuracy of estimation of FRET parameters with focus on the near-infrared spectral window. Experiments were performed in silico, in vitro, and in vivo with gate width sizes ranging from 300 ps to 1000 ps in intervals of 100 ps. For all cases, the FRET parameters were retrieved accurately and the imaging acquisition time was decreased three-fold. These results indicate that increasing the gate width up to 1000 ps still allows for accurate quantification of FRET interactions even in the case of short lifetimes such as those encountered with near-infrared FRET pairs.
关键词： fluorescence lifetime,F?rster Resonance Energy Transfer (FRET),gated ICCD,near infrared (NIR) dyes,time-resolved imaging,gate width,in vivo imaging
更新于2025-09-10 09:29:36
-
Hydrogen-Bonded Two-Component Ionic Crystals Showing Enhanced Long-Lived Room-Temperature Phosphorescence via TADF-Assisted F?rster Resonance Energy Transfer
摘要： Molecular room-temperature phosphorescent (RTP) materials with long-lived excited states have attracted widespread attention in the fields of optical imaging, displays, and sensors. However, accessing ultralong RTP systems remains challenging and examples are still limited to date. Herein, a thermally activated delayed fluorescence (TADF)-assisted energy transfer route for the enhancement of persistent luminescence with an RTP lifetime as high as 2 s, which is higher than that of most state-of-the-art RTP materials, is proposed. The energy transfer donor and acceptor species are based on the TADF and RTP molecules, which can be self-assembled into two-component ionic salts via hydrogen-bonding interactions. Both theoretical and experimental studies illustrate the occurrence of effective F?rster resonance energy transfer (FRET) between donor and acceptor molecules with an energy transfer efficiency as high as 76%. Moreover, the potential for application of the donor–acceptor cocrystallized materials toward information security and personal identification systems is demonstrated, benefitting from their varied afterglow lifetimes and easy recognition in the darkness. Therefore, the work described in this study not only provides a TADF-assisted FRET strategy toward the construction of ultralong RTP, but also yields hydrogen-bonding-assembled two-component molecular crystals for potential encryption and anti-counterfeiting applications.
关键词： thermally activated delayed fluorescence,energy transfer,cocrystallization,hydrogen bonding self-assembly,room-temperature phosphorescence
更新于2025-09-10 09:29:36
-
Resonance Energy Transfer in a Genetically Engineered Polypeptide Results in Unanticipated Fluorescence Intensity
摘要： The fluorescence intensity of a C-terminal acceptor chromophore, N-(7-dimethylamino-4-methyl coumarin (DACM), increased proportionally with 280 nm irradiation of an increasing number of donor tryptophan residues located on a β-sheet forming polypeptide. The intensity of the acceptor chromophore increased even as the length of the β-sheet edge approached 256 ?, well beyond the F?rster radius for the tryptophan-acceptor chromophore pair. The folding of the peptides under investigation was verified by circular dichroism (CD) and deep UV resonance Raman experiments. Control experiments showed that fluorescence occurred concomitantly with peptide folding. In other control experiments, the DACM fluorescence intensity of the solutions of tryptophan and DACM did not show any enhancement of DACM fluorescence with increasing tryptophan concentrations. Formation of fibrillar aggregates of the substrate peptides prepared for the fluorescence studies was undetectable by thioflavin T(ThT) fluorescence.
关键词： fluorescence,energy transfer,protein folding,photophysics,peptides
更新于2025-09-10 09:29:36
-
Manufacturing of Volumetric Glass <b>-</b> Based Composites with Single- and Double-QD Doping
摘要： Quantum dot (QD)-based light-emitting materials are gaining increased attention because of their easily tunable optical properties desired for various applications in biology, optoelectronics, and photonics. However, few methods can be used to manufacture volumetric materials doped with more than one type of QD other than QD-polymer hybrids, and they often require complicated preparation processes and are prone to luminescence quenching by QD aggregation and separation from the matrix. Here, simultaneous doping of a volumetric glass-based nanocomposite with two types of QDs is demonstrated for the first time in a single-step process using the nanoparticle direct doping method. Glass rods doped with CdTe, CdSe/ZnS, or co-doped with both QDs, are obtained. Photoluminescence and lifetime experiments confirm temperature-dependent double emission with maxima at 596 and 720 nm with mean lifetimes up to 16 ns, as well as radiative energy transfer from the short wavelength–emitting QDs to the long wavelength–emitting QDs. This approach may enable the simple and cost-efficient manufacturing of bulk materials that produce multicolor luminescence with cascade excitation pumping. Applications that could benefit from this include broadband optical fiber amplifiers, backlight systems in LCD screens, high-power LEDs, or down-converting solar concentrators used to increase the efficiency of solar panels.
关键词： energy transfer,nanoparticle direct doping,quantum dots,volumetric material with embedded quantum dots,double wavelength luminescence
更新于2025-09-10 09:29:36
-
Cooperative Chirality and Sequential Energy Transfer in Supramolecular Light-harvesting Nanotube
摘要： By constructing a supramolecular light-harvesting chiral nanotube in aqueous phase, we demonstrated the cooperative energy and chirality transfer that revealed some new aspects. It was found that a cyanostilbene-appended glutamate compound (CG) self-assembled into helical nanotubes exhibiting both supramolecular chirality and circularly polarized luminescence (CPL). When two achiral acceptors ThT and AO with different energy bands were co-assembled with the nanotube, the CG nanotube could transfer its chirality to both of the acceptors. The excitation energy could be transferred to ThT but only be sequentially transferred to AO. During such process, the CPL ascribed to the acceptor could be sequentially amplified. This work provides a new insight into the understanding the cooperative chirality and energy transfer in a chiral supramolecular system, which is more similar to the natural light-harvesting antennas.
关键词： Supramolecular chirality,Energy transfer,Light-harvesting,Circularly polarized luminescence,Supramolecular nanotube
更新于2025-09-10 09:29:36
-
Simultaneously tuning emission color and realizing optical thermometry via efficient Tb3+→Eu3+ energy transfer in whitlockite-type phosphate multifunctional phosphors
摘要： A series of Ca8ZnLa(PO4)7 (CZLPO) phosphors doped with Tb3+ and Eu3+ have been synthesized using a high-temperature solid-state method. The XRD pattern verifies that all prepared samples are attributed to whitlockite-type structure of β-Ca3(PO4)2 with R3c (161) space group. Under 366 nm excitation, the CZLPO: Tb3+, Eu3+ phosphors exhibit a tunable multi-color emission owing to energy transfer from Tb3+ to Eu3+ via a quadrupole-quadrupole interaction mechanism. The emission colors of the phosphors could be modulated from green to red under NUV (366 nm) excitation due to efficient Tb3+/Eu3+ energy transfer. The fluorescence intensity ratio (I542nm/I611nm) for the Tb3+/Eu3+ of this material displayed excellent temperature sensing properties between 298 and 498 K. Moreover, it was found that the intensity ratio was unchanged when the temperature was cycled between 298 and 498 K, thus demonstrating the recyclability of this system. These results show that CZLPO: Tb3+, Eu3+ phosphors have potential as high performance multifunctional materials for solid state lighting and temperature sensing applications.
关键词： Ca8ZnLa(PO4)7: Tb3+,Energy transfer,Eu3+,Color tuning,Temperature sensing
更新于2025-09-10 09:29:36
-
Energy transfer studies and neutral to warm white light generation in Dy3+-Sm3+ co-doped bismuth phosphate glasses for lighting applications
摘要： A series of bismuth phosphate (BiP) glasses activated with 0.5 mol% of Dy3+ and different concentrations (0.1, 0.3, 0.5, 1.0, 1.5 and 2.0 mol%) of Sm3+ ions were prepared by melt quenching technique. These are characterized through optical absorption, photoluminescence and decay measurements for spectroscopic investigations. The luminescence spectra have been studied under selected excitation wavelengths to examine the energy transfer mechanism in the present Dy3+-Sm3+ co-doped glass by varying Sm3+ ion concentration. The lifetimes of both 4F9/2 level of Dy3+ ion and 4G5/2 level of Sm3+ ion of co-doped glasses have obtained and found to be decreased with increase in Sm3+ ion concentration. The emission intensity increased with the increase of Sm3+ ion concentration (upto 1.5 mol%) which confirms the energy transfer process between Dy3+ to Sm3+ ions. The CIE chromaticity co-ordinates (x, y), correlated color temperature (CCT) and color purity (CP) were determined from the emission data. From the CIE, CCT and CP values, it can be concluded that there is a color hue from neutral to warm white light region due to Sm3+ ion concentration and selected excitation wavelength. Hence, the obtained results strongly suggest that the present Dy3+-Sm3+ co-doped bismuth phosphate glasses could be useful for lighting applications.
关键词： Correlated colour temperature,Energy transfer,Decay profiles,Photoluminescence,Dy3+-Sm3+ co-doped glasses,Colour purity
更新于2025-09-10 09:29:36
-
Using optical tweezers to construct an upconversion luminescent resonance energy transfer analytical platform
摘要： We report a new upconversion nanoparticles (UCNPs) based luminescent resonance energy transfer (LRET) analytical platform by making use of optical tweezers technology. The LRET model is designed by simultaneously conjugating Yb3+ and Er3+ co-doped UCNPs (as the donors) and tetramethyl rhodamine (TAMRA) molecules (as the acceptors) on microspheres to fabricate complex microspheres. Upon a single complex microsphere entering the three-dimensional potential well formed with a tightly focused 980 nm Guassian-shaped laser beam, it is optically trapped and concurrently the upconversion emission is excited, whereby the donor signals are transferred to the acceptors. As a proof-of-concept investigation, microRNA-21 sequences are selected as the targets, by which the distance between the two perfectly matched luminophors is controlled to several nanometers via nucleic acid hybridization. Without the involvement of luminescence amplification strategies, the proposed single microsphere based LRET method shows highly competitive sensitivity with a limit of detection down to 114 fM and satisfactory specificity towards microRNAs detection. Moreover, its practical working ability is demonstrated by credibly quantifying the absolute contents of miRNA-21 sequences in three cancer cell lines and even tracing the targets in as few as 100 cancer cells. Thus, this favorable analytical methodology provides an alternative for bioassays and holds certain potential in biomedical applications.
关键词： microRNA detection,Upconversion nanoparticle (UCNPs),Luminescent resonance energy transfer (LRET),Optical tweezers
更新于2025-09-10 09:29:36
-
Photoluminescence Tuning in Novel Bi3+/Mn4+ Co-doped La2ATiO6:(A = Mg, Zn) Double Perovskite Structure: Phase Transition and Energy Transfer
摘要： Red-emitting phosphors are indispensable componans to achieve warm white light of phosphor-converted white light emitting diodes (pc-WLEDs). However, the luminous efficiency and stability for red phosphors are still a big challenge. In this work, we develop red-emitting double perovskite phosphors La2ATiO6:Bi3+, Mn4+ (A = Mg, Zn) (LAT: Bi3+, Mn4+) and disscuss the relationship between double perovskite phosphors structure and luminescence performance in detail. By designing Mg2+/Zn2+ cation substitution, It is noteworthy that the internal quantum efficiency (IQE) is remarkeblely enhanced beyond 20%. According to Rietveld refinement results for La2Mg(1-w)ZnwTiO6:Bi3+, Mn4+ (0 ≤ w ≤ 1) (LM(1-w)ZwT:Bi3+, Mn4+) solid solution, the proposed machanism of the spectral adjustment is ascribed to the appearance of phase transition, which results in a lower local structure symmetry of [LaO12] polyhedron and variation of crystal field environment for Mn4+. Notably, it is the first time to reveal the influence of local structure variation on luminescence tuning in double perovskite structure phosphors, which could offer a guidance to develop new phosphors system. In addition, we firstly succeed in realizing Bi3+/Mn4+ co-doped energy transfer in double perovskite structure phosphors. Due to the Bi3+→Mn4+energy transfer in LAT, red emission of Mn4+ ions could be dramatically enhanced. The energy transfer efficiency of LAT: Bi3+, Mn4+ eventually reaches exceed 90%. The IQE and thermal stability are all enhanced around 30% than non-codoped samples, respectively. These results indicate that Bi3+→Mn4+energy transfer strategy could play a pivotal role in developing highly efficient red-emitting phosphor. The performance of the fabricated pc-WLEDs devices indicates that LAT:Bi3+, Mn4+ could be a promising red phosphor for near ultraviolet (n-UV) based on warm pc-WLEDs.
关键词： pc-WLEDs,Bi3+/Mn4+ co-doped,double perovskite phosphors,energy transfer,Red-emitting phosphors
更新于2025-09-10 09:29:36