Journal of Luminescence最新文献

The G-center in silicon-on-insulator (SOI) has emerged as a relevant single photon source due to the zero-phonon line at 1278 nm, matching the O-band of optical telecommunication wavelengths. Due to the weak emission of the G-center from planar SOI, it is necessary to enhance its emission, in terms of collection efficiency and fluorescence enhancement, to further study its optical properties for application in quantum technologies. Here we design a fabrication-ready SOI Mie-resonator made of a lattice of silicon nanopillars on silica to achieve the spontaneous emission enhancement of single G-centers. Using Si nanopillars lattice on silica with period and dimensions optimized, owing to the coherent superposition of the electric dipolar and magnetic quadrupolar electromagnetic Mie-scattering moments of the individual pillars to the periodic lattice, we show the G-center emission/decay rate enhancement averaged over it's possible dipole orientations is about 13 times compared to bulk. This corresponds to a fluorescence enhancement of about 125 times compared to bulk and about 5-6 times compared to an optimized single pillar with photon collection with a confocal objective. These results provide a fabrication pathway for out-of-plane single photon collection from the SOI G-center or other telecom O-band single-photon sources for their potential deployment in CMOS-compatible quantum optical technologies.

Polymer based waveguide amplifiers are the key devices to improve the performance of integrated communication systems. However, due to their comparatively low relative gain, their widespread practical application has been limited. In polymer based optical waveguide amplifiers, the size of inorganic compounds in the composite gain media has a significant impact on the gain performance of the amplifier. Up to now, there has been limited research on the size influence of inorganic compound on the gain variation in organic polymer based optical waveguide amplifiers. In this study, a series of NaLu_0.8-xY_xF₄: Yb, Er-PMMA composite polymer were used as gain media to prepare organic waveguide amplifiers working in the C-band (1530–1565 nm). The size of NaLu_0.8-xY_xF₄: Yb, Er compounds varies between 20 nm and 150 nm. In the polymer based optical waveguide amplifiers, variations in the size of the inorganic NaLu_0.8-xY_xF₄:Yb,Er compound affects not only the C-band emission intensity but also the relative gain. When the size of the inorganic compound is 65 nm, the composite gain media exhibits the maximum emission peak intensity at 1550 nm and the corresponding device achieves a maximum relative gain of 19.3 dB/cm. Our results show that the size of inorganic compounds affects the variation of luminescence intensity and ultimately the gain of waveguide amplifiers. The gain of future polymer optical waveguide amplifiers can be improved by this method.

Lead halide perovskite quantum dots (QDs) have garnered significant attention due to their tunable band gaps, unique quantum confinement effects, and high photoluminescence quantum yields (PLQYs). Among them, Organic-inorganic QDs make them promising candidates for optoelectronic devices such as quantum dot light-emitting diodes (QLEDs), solar cells, lasers, and photodetectors. However, the toxicity of lead (Pb) has raised environmental and health concerns, hindering their industrial application. To alleviate concerns about heavy metals Pb, extensive research has been conducted on B-site doping and the development of lead-free perovskites. Herein, we firstly developed B-site doping strategy on organic-inorganic hybrid perovskite QDs via rare-earth elements. Neodymium (III) (Nd³⁺) doped FAPbBr₃ QDs were prepared through the ligand-assisted reprecipitation method at room temperature. The B-site doping strategy could alleviate the heavy metal problem of Pb and modulate the band gap of FAPbBr₃ QDs facilely. The results demonstrated that increasing the concentration of Nd³⁺ can change the emission of FAPbBr₃ QDs from pure green to deep blue. Specifically, we achieved highly pure blue emission (∼438 nm) with a full width at half maximum (FWHM) of 13 nm for Nd³⁺-doped FAPbBr₃ QDs. Time-resolved photoluminescence (TRPL) spectroscopy revealed a decrease in the lifetime of FAPbBr₃ QDs from 22.86 to 15.46 ns as the doping concentration increased. Additionally, we fabricated a white LED (WLED) utilizing blue-emitting Nd³⁺-doped FAPbBr₃, green-emitting FAPbBr₃ QDs, and red QDs, achieving a white emission color coordinate of (0.33, 0.36). This study pioneers the application of B-site rare-earth doping in organic-inorganic hybrid perovskite QDs, demonstrating that B-site composition engineering is a reliable strategy to further exploit the perovskite family for wider optoelectronic applications.

The local surface plasmon resonance (LSPR) effect and scattering properties of gold nanoparticles are effective ways to improve the light extraction efficiency of organic light-emitting diodes (OLEDs). Here five different kinds of urchin-like gold nanoparticles (UGNs) were synthesized using the seed-mediated method. The finite-difference time-domain (FDTD) method was used to calculate the near-field local and far-field scattering properties of various sea urchin-like gold nanoparticles. All five types of UGNs demonstrated certain levels of light enhancement within the visible band. The flexible OLED devices were created by doping five different types of nanoparticles into the flexible substrates. The hollow UGNs device exhibited a maximum current efficiency of 124.25 cd/A, a maximum power efficiency of 131.27 lm/W, and a maximum EQE of 45.54 %. When compared to undoped flexible devices, the maximum current efficiency, the maximum power efficiency, and the maximum EQE increase by 132 %, 82 %, and 36 %, respectively. The results indicate that combining the flexible conductive substrate and UGNs is an effective strategy for improving light extraction from flexible OLEDs. This enhancement effect originates from UGNs acting as a scattering layer to reduce total light reflection, and the luminous intensity of the device is improved due to the LSPR of sea urchin-like nanoparticles.

RE_2−xEu_xSn₂O₇ (RE:La³⁺ and Ho³⁺, x:0.10) materials were synthesized having both pholuminescence and piezoelectric properties using with solid state reaction method at various reaction temperature and heating duration in open atmosphere. The thermal behaviors, crystal system, surface morphology, EDX analysis, Curie tempereture, photoluminescent properties, dielectric and piezoelectric properties of Eu³⁺ ions doped La₂Sn₂O₇ and Ho₂Sn₂O₇ were investigated. Both multi-functional smart materials show dielectric, piezoelectric properties and photoluminescence properties which is responsible transitions of doping Eu³⁺ ions.

We investigated a novel inorganic photochromic material, Sm³⁺ and Bi³⁺-codoped LiNbO₃, which was synthesized using a traditional high-temperature solid-state method. In our samples, Sm³⁺ acted as an orange-red luminescence center, whereas the codopant Bi³⁺ created traps within the host lattice. Doping with Bi³⁺ suppressed the orange-red emission of Sm³⁺ and significantly improved the UV–visible photoswitching photochromic (PC) behavior and the related photoluminescence modulation associated with defect formation by Bi³⁺. Moreover, our samples exhibited good persistent luminescence in close relation to the PC behavior. Furthermore, our samples retained their ferroelectric properties even after doping with Sm³⁺/Bi³⁺. These excellent optical properties suggest that Sm³⁺ and Bi³⁺-codoped LiNbO₃ can be promising inorganic photochromic materials for optical information storage.

This research comprehensively investigates the interplay between luminescence and magnetic phenomena in the zinc blende phase of manganese-doped and undoped zinc sulfide. The study involves the synthesis of zinc sulfide nanocrystals through a soft chemical method, followed by an in-depth experimental characterization. Theoretical studies were conducted using a 2 × 2 × 2 supercell model with 64 atoms to explore the impact of native defects and manganese doping on zinc sulfide's the electronic, magnetic, and optical properties. The research findings offer a detailed physical description of magnetic and optic phenomena observed, underpinned by a strong correlation between theoretical predictions and experimental results. An essential contribution of this work is developing a depiction that elucidates the relationship between optical transitions and spin-exchange in the context of these phenomena.

Latent fingerprint detection is one of the promising technique in forensic science. Here, a cation replacement strategy in Eu³⁺-activated K_1-yNa_yGaGeO₄ phosphor under excitation by near ultraviolet (NUV) light was proposed for the first time. The corresponding crystal structure, luminescent property, thermal stability, and color purity were systematically investigated. These results indicate that the high photoluminescence (PL) intensity and prominent ultraviolet absorption of the phosphors can contribute to obvious suppression of background interference of substrate and good visualization for the fluorescent LFP images. The optimized K_0.65Na_0.15GaGeO₄:0.2Eu³⁺ phosphor reveals a great thermal stability and color shift resistance from 300 to 500 K. The Commission International del'Eclairage (CIE) chromaticity coordinates of K_0.65Na_0.15GaGeO₄:0.2Eu³⁺ were measured to be (0.6637,0.3409), and the color purity was calculated as 91.1 %. The obtained results suggest that the K_0.65Na_0.15GaGeO₄:0.2Eu³⁺ phosphor exhibits good potential for high resolution and high sensitivity LFP detection and LED application.

Zero-dimensional (0D) organic-inorganic Cu(I)-based halides have garnered significant attention due to their low toxicity, efficient emission, and moderate fabrication conditions. However, the challenge remains in developing stable and efficient 0D hybrid Cu(I)-based halides for effective X-ray imaging. In this study, a yellow-emitting 0D hybrid copper halide, (ETPP)₂Cu₂I₄ (Ethyl triphenylphosphonium, ETPP), was successfully synthesized via a slow evaporation method. This compound demonstrated an impressive steady-state light yield of 23,200 photons/MeV under X-ray radiation and an ultralow detection limit of 150.9 nGy_air s⁻¹, approximately 35 times lower than the standard medical examination dosage. Utilizing a vacuum-filtration method, we fabricated a flexible film that outperforms traditional methods and achieved an exceptional X-ray imaging resolution of 16.0 lp/mm. This study introduces a novel approach to fabricating high-performance X-ray imaging scintillators based on 0D Cu-based halides, showcasing excellent scintillation performance and stability for non-destructive testing.

Mechanical stimulus-responsive materials are generally considered to be closely related to molecular packing in the solid state, underscoring the significance of regulating molecular packing via precise molecular design. In this study, flexible alkyl substituents were employed to adjust the molecular packing. By modifying alkyl substituents, predictable changes in the molecular packing of their derivatives were observed, resulting in adjustable ML properties. The DPA-PYZ-TB with a tert-butyl-side chain exhibited strong ML and MC stimulus response signals. The enhanced ML and MC performance can be attributed to the effective suppression of non-radiation through the helical crystal arrangement and strong intermolecular interactions. The relationship between molecular arrangement and ML/MC properties was validated through analysis of the single crystal structure and corresponding experimental results. This study offers valuable insights into the enigmatic ML process and the development of efficient luminous materials that utilize both MC and ML.