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Near-infrared laser driven white light continuum generation: materials, photophysical behaviours and applications
摘要： The pursuit of efficient light sources has stimulated continued effort in the search of materials and methods for generating white light emission. In addition to the white light produced by light-emitting diodes (LEDs) and fluorescent lamps that involves spectral conversion of high energy to low energy emission, recent studies showed that it was also possible to produce white visible light by irradiating different active materials with near-infrared (NIR) constant-wave (CW) lasers. In this review, we begin by introducing and categorizing different materials that exhibit NIR laser driven white light emission, including normal inorganic phosphors, organometallic compounds, graphene, etc. We then discuss the photophysical behavior of this process in terms of optical spectra, temperature evolution and photoelectric response. Different mechanisms of while light generation are analyzed afterwards, and the possibility of a more general physical picture of this process is discussed. This review is concluded with a summary of the current understanding and discussion on potential applications and future perspectives.
关键词： graphene,near-infrared laser,optical spectra,photoelectric response,organometallic compounds,temperature evolution,inorganic phosphors,photophysical behavior,white light emission
更新于2025-09-23 15:19:57
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Unidirectional Branching Growth of Dipeptide Single Crystals for Remote Light Multiplication and Collection
摘要： Herein, we report on the unidirectional branched assembly of diphenylalanine dipeptide through a one-step rapid evaporation process. Large numbers of crystalline tubular branches with smooth surfaces are developed from a hexagonal solid microrod mimicking a “Christmas tree”. Density functional theory suggests the formation of tubular diphenylalanine aggregates with cis isomers. The diphenylalanine branched assembly shows good optical waveguide properties that can transmit light homogenously along the crystal fibers as well as harvest light from the tips of branches to the microrod terminals. These findings hold importance in the development of bio-inspired optical fibers for information transmission in a microscale.
关键词： single crystal,self-assembly,light emission,optical waveguide,diphenylalanine
更新于2025-09-23 15:19:57
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Light from van der Waals quantum tunneling devices
摘要： The understanding of and control over light emission from quantum tunneling has challenged researchers for more than four decades due to the intricate interplay of electrical and optical properties in atomic scale volumes. Here we introduce a device architecture that allows for the disentanglement of electronic and photonic pathways—van der Waals quantum tunneling devices. The electronic properties are defined by a stack of two-dimensional atomic crystals whereas the optical properties are controlled via an external photonic architecture. In van der Waals heterostructures made of gold, hexagonal boron nitride and graphene we find that inelastic tunneling results in the emission of photons and surface plasmon polaritons. By coupling these heterostructures to optical nanocube antennas we achieve resonant enhancement of the photon emission rate in narrow frequency bands by four orders of magnitude. Our results lead the way towards a new generation of nanophotonic devices that are driven by quantum tunneling.
关键词： van der Waals heterostructures,inelastic electron tunneling,nanophotonics,light emission,quantum tunneling,optical antennas
更新于2025-09-19 17:15:36
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Many-body States Description of Single-molecule Electroluminescence Driven by Scanning Tunneling Microscope
摘要： Electron transport and optical properties of a single molecule in contact with conductive materials have attracted considerable attention owing to their scientific importance and potential applications. With recent progresses of experimental techniques, especially by the virtue of scanning tunneling microscope (STM)-induced light emission, where the tunneling current of the STM is used as an atomic-scale source for induction of light emission from a single molecule, it becomes possible to investigate single-molecule properties at sub-nanometer spacial resolution. Despite extensive experimental studies, the microscopic mechanism of electronic excitation of a single molecule in STM-induced light emission is yet to be clarified. Here we present a formulation of single-molecule electroluminescence driven by electron transfer between a molecule and metal electrodes based on a many-body state representation of the molecule. The effects of intra-molecular Coulomb interaction on conductance and luminescence spectra are investigated using the nonequilibrium Hubbard Green's function technique combined with first-principles calculations. We compare simulation results with experimental data and find that the intra-molecular Coulomb interaction is crucial for reproducing recent experiments for a single phthalocyanine molecule. The developed theory provides a unified description of both electron-transport and optical properties of a single molecule in contact with metal electrodes driven out of equilibrium, and thereby it contributes to a microscopic understanding of optoelectronic conversion in single molecules on solid surfaces and in nanometer-scale junctions.
关键词： Single molecule luminescence,exciton formation,nonequilibrium Hubbard Green's function technique,time-dependent density functional theory (TDDFT),scanning tunneling microscope-induced light emission,Vibronic interaction
更新于2025-09-19 17:15:36
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Tailoring of structural and photoluminescence emissions by Mn and Cu co-doping in 2D nanostructures of ZnS for the visualization of latent fingerprints and generation of white light
摘要： Tailoring of structural and photoluminescence emissions by Mn and Cu co-doping in 2D nanostructures of ZnS for the visualization of latent fingerprints and generation of white light. There has been a recent demand for the development of luminescent materials for visualizations of latent fingerprints (LFPs) for achieving enhanced security. Also recently, there has been a new research trend in the development of 2D materials from non-layered semiconductors with strong luminescence properties in the visible region. The conventional growth process of luminescent materials limits their capacity of tuning the structure and light emission efficiency. However, multi-atom doping provides an additional degree of freedom to tune the basic morphologies and optical properties of luminescent semiconductors by controlling the defect levels. Here, by using a simple chemical technique, multi-atom (Cu and Mn) doped rarely reported 2D nanosheets of zinc sulphide (ZnS) have been grown. Thus, a stable high fluorescence efficiency of ～62% in the visible region has been realized for the visualization of LFPs. Furthermore, near-white light emission has been demonstrated by coating the synthesized materials with a suitable doping concentration on a commercially available UV-LED chip. The proposed technique may be utilized further to build up other 2D nanostructured materials for multifunctional applications in solid state lighting, LFPs and forensic science.
关键词： ZnS,2D materials,latent fingerprints,co-doping,luminescent materials,white light emission
更新于2025-09-19 17:15:36
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Rare earth-free composites of carbon dots/metal-organic framework as white light-emitting phosphor
摘要： Over the last few years, numerous efforts have been made to develop white light-emitting metal-organic frameworks (MOFs), due to the useful features of MOFs such as ultrahigh surface areas and tunable pore architecture. However, rare earth (RE) ions are most commonly applied as phosphors in these materials so far, raising device cost and environmental concerns. Here, we designed a new type of RE-free material capable of white light-emission upon excitation at 365 nm, with the photoluminescence quantum yield in solid state reaching 37%, fabricated by compositing carbon dots (CDs) with Zr(IV)-based MOF. WLEDs constructed by depositing the CDs/Zr-MOF nanocomposite on a commercial UV LED chip feature a CIE chromaticity coordinate at (0.31, 0.34), high color rendering index (CRI) of 82, and luminous efficiency of 1.7 lm/W.
关键词： carbon dots,rare-earth-free luminophores,white-light-emission,Zr-MOFs,down-conversion LEDs
更新于2025-09-19 17:15:36
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Towards white light emission from a hybrid thin film of a self-assembled ternary samarium( <scp>iii</scp> ) complex
摘要： A new samarium complex [Sm(hfaa)3(Py-Im)] (ML) was synthesized by utilizing hexafluoroacetylacetone (hfaa) and 2-(2-pyridyl)benzimidazole (Py-Im) as coordinating ligands. A single crystal X-ray analysis shows that in the solid-state the complex dimerizes through intermolecular hydrogen-bonding with N–H···O (2.127 ?) and N–H···F (2.576 ?) interactions. The complex in the solid-state displayed highly monochromatic brilliant red emission with Commission International de I’Eclairage (CIE) color coordinates of 0.6532; 0.3336, with a remarkably long luminescence lifetime (≈ 204.47 ± 4.043 μs) and a high intrinsic quantum yield (≈ 6.60 %). Furthermore, the complex in different organic media displayed color tunability from orange (CIE; 0.6071; 0.3568) to violet (CIE; 0.3634; 0.2144) with from 105.50 ± 0.143 – 14.27 ± 0.033 μs. Hybrid and flexible thin films obtained by doping different concentrations (1%, 2%, 4% and 6%) of the complex into the poly(urethane) (PU) polymer matrix also exhibited color tunability from violet (CIE; 0.3380; 0.2162) to light orange (CIE; 0.5666; 0.3408). White light emission from a 1% doped thin film of the complex was realized by changing the excitation wavelength. The new material could be a potential candidate for the fabrication of full-color display devices and for solid-state lighting (SSL) applications.
关键词： luminescence,white light emission,color tunability,samarium complex,solid-state lighting
更新于2025-09-19 17:13:59
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Hue‐ and Chromaticity‐Based Exploration of Surface Complexation‐Induced Tunable Emission from Non‐Luminescent Quantum Dots
摘要： Herein we report the use of a hue parameter of HSV (Hue, Saturation and Value) color space—in combination with chromaticity color coordinates—for exploring the complexation-induced luminescence color changes, ranging from blue to green to yellow to white, from a non-luminescent Fe-doped ZnS quantum dot (QD). Importantly, the surface complexation reaction helped a presynthesized non-luminescent Fe-doped ZnS QD to glow with different luminescence colors (such as blue, cyan, green, greenish-yellow, yellow) by virtue of the formation of various luminescent inorganic complexes (using different external organic ligands), while the simultaneous blue- and yellow-emitting complex formation on the surface of non-luminescent Fe-doped ZnS QD led to the generation of white light emission, with a hue mean value of 85 and a chromaticity of (0.28,0.33). Furthermore, the surface complexation-assisted incorporation of luminescence properties to a non-luminescent QD not only overcomes their restricted luminescence-based applications such as light-emitting, biological and sensing applications but also bring newer avenues towards unravelling the surface chemistry between QDs and inorganic complexes and the advantage of having an inorganic complex with QD for their aforementioned useful applications.
关键词： quantum dots,inorganic complexes,photoluminescence,hue,chromaticity,white light emission
更新于2025-09-19 17:13:59
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Realization of Excitation Wavelength Independent Blue Emission of ZnO Quantum Dots with Intrinsic Defects
摘要： Eco-friendly cation metal oxide quantum dots (QDs) are one of promising candidates to replace for QDs containing expensive Indium (In) or hazardous Cd- and Pb-elements. Super-Eg excitation wavelength (λex) dependent Zni-VO complex defects related characteristic emissions of green, yellow, and orange-red from ZnO QDs are completely inhibited by reducing oxygen vacancies through the hybridization of Zn interstitials in ZnO QDs with anti-bonding O-states of graphene oxide (GO) QDs. Thus, only λex independent violet-purple-blue (V-P-B) emission resulting from transitions among Frenkel pairs (Zni 0-VZn) and the defects Zni 0-Oi in ZnO-GO QDs with a high photoluminescence quantum yield (PLQY) of 92% is successfully achieved. White-light emission from PL QD-LEDs is achieved using a mixture of ZnO and ZnO-GO QDs with CIE (0.32, 0.34) excited by a UV LEDs chip (λ=365 nm). Further, ZnO-GO QD-based deep-blue LEDs (λ=438 nm) with luminance of 1980 cd/m2, a luminous efficacy (LE) of 2.53 cd/A, and external quantum efficiency (EQE) of 2.78 % with CIE (0.16, 0.11) are also realized.
关键词： eco-friendly fluorescent materials,excitation independent deep blue light emission,photoluminescence quantum efficiency,Zni-Vo complex defects,ZnO-Graphene Oxide quantum dots
更新于2025-09-19 17:13:59
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Noninverse dynamics of a quantum emitter coupled to a fully anisotropic environment
摘要： Anisotropic nanophotonic structures can couple the levels of a quantum emitter through the quantum interference effect. In this paper we study the coupling of quantum emitter excited states through the modes of a fully anisotropic structure, a structure for which all directions are physically nonequivalent. We consider an anisotropic metasurface as an illustrative example of such a structure. We point out another degree of freedom in controlling the temporal dynamics and spectral pro?les of quantum emitters; namely, we show that a combination of the metasurface anisotropy and tilt of the emitter quantization axis with respect to the metasurface normal results in nonsymmetric dynamics between the transitions of electrons from the left-circular state to the right-circular state and in the inverse process. Our ?ndings give an additional mechanism for control over light emission by quantum systems and can be utilized for probing active transitions of quantum emitters.
关键词： metasurface,light emission control,anisotropic environment,quantum emitter,quantum interference
更新于2025-09-16 10:30:52