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Employing a Narrow-bandgap Mediator in Ternary Solar Cells for Enhanced Photovoltaic Performance
摘要： Ternary organic solar cells (OSCs) provide a convenient and effective means to further improve the power conversion efficiency (PCE) of binary ones via composition control. However, the role of the third component remains to be explored in specific binary systems. Herein, we report ternary blend solar cells by adding the narrow-bandgap donor PCE10 as the mediator into the PBDB-T:IDTT-T binary blend system. The extended absorption, efficient fluorescence resonance energy transfer, enhanced charge dissociation and induced tighter molecular packing of the ternary blend films enhance the photovoltaic properties of devices and deliver a champion PCE of 10.73% with an impressively high open-circuit voltage (VOC) of 1.03 V. Good miscibility and similar molecular packing behavior of the components guarantee the desired morphology in the ternary blend films, leading to solar cell devices with over 10% PCEs at a range of compositions. Our results suggest ternary systems with properly aligned energy levels and overlapping absorption amongst the components hold great promises to further enhance performance of corresponding binary ones.
关键词： ternary solar cell,energy transfer,induced crystallization property,non-fullerene acceptors,molecular mediator
更新于2025-09-23 15:19:57
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Study of energy transfer from Bi3+ to Tb3+ in Y2O3 phosphor and its application for W-LED
摘要： Y2O3 activated with different activators were prepared by co-precipitation method. The prepared phosphors were characterized by XRD, SEM and photoluminescence (PL) techniques. The Tb3+ doped Y2O3 phosphor shows characteristic green emission due to 5D4 to 7Fj transitions of Tb3+ ion. The Bi3+ doped Y2O3 phosphor shows PL emission in blue region due to the transition between excited 3P1 state and ground state 1S0 of Bi3+ ion. The multiple systems of Tb3+emission lines in Y2O3:Tb3+ and two types of excitation and emission spectra of Y2O3:Bi3+ phosphors are due to two Y3+ sites in the host structure with C2 and S6 symmetries. Due to the addition of transition metal ion Bi3+ in Y2O3:Tb3+ lattice, the excitation efficiency is enhanced throughout the spectral range from 300 nm to 400 nm. Bi3+ ions absorb N-UV radiation and, subsequently, the energy is transferred from the sensitizer Bi3+ to activator Tb3+ and emitted via 5D4 to 7Fj transitions of Tb3+ ion. From the spectral properties of Y2O3:Bi3+ and Y2O3:Tb3+, Bi3+, it is established that the prepared phosphors are useful in near UV excited LED (solid state lighting) application.
关键词： Phosphor,Y2O3,W-LED,Energy transfer
更新于2025-09-23 15:19:57
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Multi-phased cesium lead iodide quantum dots with large stokes shift
摘要： Lead halide perovskite quantum dots (QDs) have emerged as one of the most promising candidates for lighting and biomedical applications. However, further applications are limited by energy transfer of F?rster resonance energy transfer (FRET) or photon reabsorption between different QDs due to QDs with small Stokes shifts. Here, we first report intrinsic cesium lead iodide QDs with large Stokes shifts from 262 to 289 nm with PL peaks in the range of 630 to 658 nm. We show that the large Stokes shift is attributed to the morphology of QDs with multiple phases. Our results in intrinsic lead iodide perovskite QDs with large Stokes shift may open new avenues in resolving energy transfer in biomedical and lighting applications.
关键词： Energy transfer,Perovskite quantum dots,Large Stokes shift,Luminescence,Nanocrystalline materials
更新于2025-09-23 15:19:57
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Over 15% Efficiency in Ternary Organic Solar Cells by Enhanced Charge Transport and Reduced Energy Loss
摘要： In this study, an efficient ternary bulk-heterojunction (BHJ) organic solar cell (OSC) is demonstrated by incorporating two acceptors, PC61BM and ITC6-4F with a polymer donor (PM6). It reveals that the addition of PC61BM not only enhances the electron mobility of the derived BHJ blend but also facilitates the exciton dissociation, resulting in a more balanced charge transport alongside with reduced trap-assisted charge recombination. Consequently, as compared to the pristine PM6:ITC6-4F device, the optimal ternary OSC is revealed to deliver an improved power conversion efficiency (PCE) of 15.11% with boosted JSC, VOC and FF simultaneously. The resultant VOC and FF are among the highest values recorded in the literature for the ternary OSCs with PCE exceeding 15%. This result thus suggests that besides improving the charge transport characteristics in devices, incorporating fullerene derivative as part of the acceptor can also improve the resultant VOC, which can reduce the energy loss to realize efficient organic photovoltaic.
关键词： energy transfer,charge transport,fullerene derivative acceptor,open circuit voltage,ternary organic solar cells
更新于2025-09-23 15:19:57
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Visible-Light-Driven Rotation of Molecular Motors in a Dual-Function Metala??Organic Framework Enabled by Energy Transfer
摘要： The visible-light driven rotation of an overcrowded-alkene based molecular motor strut in a dual-function metal-organic framework (MOF) is reported. Two types of functional linkers, a palladium-porphyrin photosensitizer and a bispyridine derived molecular motor were used to construct the framework capable of harvesting low-energy green light to power the rotary motion. The molecular motor was introduced in the framework using the post synthetic solvent assisted linker exchange (SALE) method and the structure of the material was confirmed by powder (PXRD) and single crystal X-ray (SC-XRD) diffraction. The large decrease in the phosphorescence lifetime and intensity of the porphyrin in the MOFs upon introduction of the molecular motor pillars confirms efficient triplet-to-triplet energy transfer between the porphyrin linkers and molecular motor. Near infrared Raman spectroscopy revealed that the visible light driven rotation of the molecular motor proceeds in the solid state at rates similar to those observed in solution.
关键词： molecular motors,metal-organic frameworks,molecular machines,energy transfer
更新于2025-09-23 15:19:57
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Off-Resonance Control and All-Optical Switching: Expanded Dimensions in Nonlinear Optics
摘要： The theory of non-resonant optical processes with intrinsic optical nonlinearity, such as harmonic generation, has been widely understood since the advent of the laser. In general, such effects involve multiphoton interactions that change the population of each input optical mode or modes. However, nonlinear effects can also arise through the input of an off-resonant laser beam that itself emerges unchanged. Many such effects have been largely overlooked. Using a quantum electrodynamical framework, this review provides detail on such optically nonlinear mechanisms that allow for a controlled increase or decrease in the intensity of linear absorption and fluorescence and in the efficiency of resonance energy transfer. The rate modifications responsible for these effects were achieved by the simultaneous application of an off-resonant beam with a moderate intensity, acting in a sense as an optical catalyst, conferring a new dimension of optical nonlinearity upon photoactive materials. It is shown that, in certain configurations, these mechanisms provide the basis for all-optical switching, i.e., the control of light-by-light, including an optical transistor scheme. The conclusion outlines other recently proposed all-optical switching systems.
关键词： absorption,nonlinear optics,all-optical switch,resonance energy transfer,fluorescence,FRET,optical transistor,multiphoton process,laser action,second harmonic generation
更新于2025-09-23 15:19:57
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Ultrahigh brightening of infrared PbS quantum dots via collective energy transfer induced by a metal-oxide plasmonic metastructure
摘要： We demonstrate a solution-processed heterojunction interface formed via addition of a thin buffer layer of CdSe/ZnS quantum dots to a functional metal oxide plasmonic metastructure (FMOP) can set up a collective inter-quantum dot energy transport process, significantly enhancing the emission of infrared PbS quantum dots. The FMOP includes a Schottky junction, formed via deposition of a Si layer on arrays of Au nanoantennas, and a Si/Al oxide charge barrier. We show when these two junctions are separated from each other by about 15 nm and the CdSe/ZnS quantum dot buffer layer is placed in touch with the Si/Al oxide junction, the quantum efficiency of an upper layer of PbS quantum dots can increase by about one order of magnitude. These results highlight a unique energy circuit formed via collective coupling of the CdSe/ZnS quantum dots with the hybridized states of plasmons and diffraction modes of the arrays (surface lattice resonances) and coupling between such resonances with PbS QDs via lattice-induced photonic modes.
关键词： exciton-plasmon coupling,plasmons,collective,PbS quantum dots,metallic nanoantennas,surface lattice resonances,energy transfer
更新于2025-09-23 15:19:57
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Realizing bright blue-red color-tunable emissions from Gd2GeO5:Bi3+,Eu3+ phosphors through energy transfer toward light-emitting diodes
摘要： Novel Bi3t, Eu3t co-doped Gd2GeO5 (GGO) phosphors were prepared by a high-temperature solid-state reaction method. X-ray diffraction, photoluminescence (PL), CIE chromaticity coordinates, internal quantum efficiency (IQE), and temperature-dependent PL spectra were applied to analyze the as-obtained phosphors. The emission spectra of the GGO:Bi3t, Eu3t phosphors showed both a broad blue band of Bi3t ions emission centered at 453 nm and the characteristic sharp red emission lines of Eu3t ions, corresponding to the 3P1→1S0 allowed transition of the Bi3t ions and the 5D0→7FJ (J ? 0, 1, 2, 3, 4) transitions of the Eu3t ions, respectively. Notably, the as-prepared GGO:Bi3t, Eu3t phosphors exhibited color-tunable emissions from blue (Bi3t) to red (Eu3t) with increasing the Eu3t doping concentration via a high-efficiency energy transfer process. Moreover, the mechanism of energy transfer from Bi3t to Eu3t ions was determined to be the dipole-quadrupole interaction. Impressively, the optimal GGO:0.05Bi3t, 0.12Eu3t phosphors had an outstanding IQE as great as 88% and good thermal stability. All these meaningful results demonstrated that blue-red color-tunable GGO:Bi3t, Eu3t phosphors have potential applications in white light-emitting diodes (LEDs) and plant growth LEDs.
关键词： Gd2GeO5,Energy transfer,Phosphors,Eu3t,Bi3t,Color-tunable emissions
更新于2025-09-23 15:19:57
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Modulating Charge-Carrier Dynamics in Mn-Doped All-Inorganic Halide Perovskite Quantum Dots through the Doping-Induced Deep Trap States
摘要： Transition metal ions doping has been demonstrated effective to tune the photoluminescence properties of perovskite quantum dots (QD). However, it would inevitably introduce defects in the lattice. As the Mn concentration increases, the Mn dopant PL quantum yield (PLQY) first increases and then decreases. Herein, the influence of the dopant and the defect states on the photophysics in Mn doped CsPbCl3 QDs was studied by time-resolved spectroscopies, while the energy levels of the possible defect states were analyzed by Density Functional Theory (DFT) calculations. We reveal the formation of deep interstitials defects (Cli) by Mn2+ doping. The depopulation of initial QDs exciton states is a competition between exciton-dopant energy transfer (ET) and defect trapping at an early time-scale (< 100 ps), which determines the final PLQY of the QDs. The present work establishes a robust material optimization guideline for all the emerging applications where high PLQY is essential.
关键词： photoluminescence,energy transfer,Mn-doped,CsPbCl3,DFT calculations,defect states,quantum dots
更新于2025-09-23 15:19:57
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Multia??enzyme detection and ina??situ monitoring of enzyme activity by bending CE using quantum dotsa??based polypeptide substrate
摘要： Multi-enzyme detection and monitoring enzyme activity in situ are significant for the disease to diagnose. This study aims to develop a quantum dots (QDs)-based nanoprobe Cyanine5-DDDLEVLFQFPGLVPRGSGGHHHHHH-QDs (Cy5-LEVLVP-QD), which is able to detect two enzymes inside a bent capillary using CE. Cy5-LEVLVP and QDs were allowed to bind with each other through metal affinity interaction and then injected the Cy5-LEVLVP-QD complex into a capillary with different bends, followed by related enzyme that can cleave the Cy5-LEVLVP peptide. The fluorescence of Cy5 was excited by QDs due to F?rster resonance energy transfer (FRET). By monitoring the peaks produced by the original Cy5-LEVLVP-QD complex and a significant fluorescence change, sensitive analysis of two different enzymes was conducted. Therefore, the novel approach of using capillaries with semicircular bends could prove particularly useful for enzyme investigating in disease.
关键词： CE,enzyme,F?rster resonance energy transfer,peptide,quantum dots
更新于2025-09-23 15:19:57