Advanced Optical Materials最新文献

Transforming MXene Impurities into Luminescent Assets

Laser irradiation transforms aluminum impurities of MXenes into embedded ruby centers featuring narrowband luminescence. This technique offers minimally destructive grain-resolved purity control, repurposing flaws into functional probes. More details can be found in the Research Article by Ilya A. Zavidovskiy, Valentyn S. Volkov, Sergey M. Novikov, Alexey D. Bolshakov, and co-workers (DOI: 10.1002/adom.202501407).

Multifunctional mmWave Metasurfaces

This work presents a multifunctional diffractive neural network–designed metasurface capable of generating multiple holographic patterns in the W-band (86?GHz) while mitigating mutual coupling through phase smoothing. Experimental validation and broadband analysis (72–100 GHz) confirm high-fidelity wavefront control, demonstrating a passive, multifunctional mmWave holographic platform. More details can be found in the Research Article by Miguel Beruete and co-workers (DOI: 10.1002/adom.202502746).

2D Dion-Jacobson (DJ) ferroelectric perovskites show outstanding potential for self-powered X-ray detection due to their high bulk resistivity and robust bulk photovoltaic effect (BPVE). Existing literature generally considered distortion of inorganic octahedral cages as detrimental to their photoelectric properties. Herein, this study demonstrates that larger distortion may be designed to attain more stable structures by promoting stronger hydrogen bonding between the inorganic cage and the organic chains, thus effectively suppressing ion migration. Furthermore, lattice distortion triggers the formation of electric dipoles, inducing spontaneous polarity and thereby augmenting the collection efficiency of photo generated charges. Leveraging the out-of-plane ferroelectric polarity of 4AMPPbI₄, a self-powered X-ray detection is pioneered with the vertical structure, offering superior integration and assembly for practical applications compared to lateral-structures. The resulting X-ray detector exhibits exceptional performance, featuring a low noise current of 7.53 pA and an impressive self-powered sensitivity of 234.74 µC Gy_air⁻¹ cm⁻² at zero bias, surpassing all 2D self-powered detectors in detection limits (6.6 nGy_air s⁻¹). Moreover, the device demonstrates commendable storage stability, retaining 95.9% initial sensitivity over 60 days under a 50V bias and 94.7% over 30 days in self-powered mode.

Tin (Sn)-based perovskites are promising materials for perovskite-based light-emitting diodes (PeLEDs) that avoid toxic lead. However, the performance of Sn-based PeLEDs lags behind that of their lead analogues due to uncontrolled crystallization, the susceptibility of Sn(II) to oxidation, and high defect densities. In this study, ammonium thiocyanate (NH₄SCN) is used as an additive in DMSO-free perovskite precursor solution to afford Sn-based perovskites that are evaluated in PeLEDs. NH₄SCN modulates the crystallization process in the solution phase to improve the morphology and crystallinity of the resulting 2D perovskite films and inhibits the oxidation of Sn(II) to Sn(IV), a problem observed in DMSO. Transient terahertz spectroscopy reveals that NH₄SCN-based perovskite films have a higher free carrier density compared to the control films, indicative of reduced defect density. Consequently, pure-red Sn-based PeLEDs with an emissive peak of 629 nm achieve an external quantum efficiency of ≈1.4%, with an operating half-life of >11 min. These findings provide valuable insights into the preparation of lead-free perovskite materials avoiding DMSO for application in optoelectronic devices.

Materials with broadband high solar absorptance and excellent thermal stability are crucial for solar energy utilization. The distinct spectral separation between electronic transitions and carrier absorption leads to limited broadband absorption efficiency in ceramics. Strategic design of structural units with tunable absorption and bandwidth is essential to overcome spectral limitations for broadband solar harvesting. This study establishes an engineering strategy that synergistically exploits cation disorder and Jahn-Teller distortions in spinel to achieve enhanced absorption. Through strategic incorporation of [CuO₆] and [CuO₄] structural units into MgAl₂O₄, Mg_0.4Cu_0.6Al₂O₄ achieves a remarkable solar absorptance of 94.9% over 0.2–8 µm and demonstrates impressive thermal stability with less than 1.5% absorptance loss after annealing at 1300 °C for 100 h. The enhanced absorption is attributed to Jahn-Teller distortions in both [CuO₄] tetrahedra and [CuO₆] octahedra, which induce significant multiple splitting of Cu-3d orbitals, enhancing electronic transitions and carrier absorption. The developed material exhibits broadband solar absorptance, high-temperature stability, and low density among oxide ceramics, making it a promising candidate for concentrated solar absorbers. These findings provide fundamental insights into the design of high-performance solar absorbers through targeted manipulation of structural units and coordination environments.

Localized quantum emitters in transition-metal dichalcogenides (TMDs) have recently emerged as solid-state candidates for on-demand sources of single photons. Due to the role of strain in the site-selective creation of TMD emitters, their hybrid integration into photonic structures such as cavities and waveguides is possible using pick-and-place methods. Here, quantum emission from a hybrid structure consisting of a monolayer of WSe₂ interfaced with horizontally aligned InP nanowires (NWs) is investigated. These experiments reveal multiple narrow and bright emission peaks in the 715–785 nm spectral range and g⁽²⁾(0) as low as 0.049, indicating strong antibunching and good single photon purity. The well-defined facets of the InP NWs shape the local strain landscape, enabling controlled formation of localized emitters in the WSe₂ monolayer.

Eliminating lattice disorder in quantum dots (QDs) is critical for achieving high-performance quantum dot light-emitting diodes (QLEDs), as such disorder directly disrupts the uniformity of elemental distribution and degrades their optical properties. Here, a tertiary amine-mediated synthesis strategy is reported that utilizes nucleophilic reagents to regulate the coordination kinetics of cationic precursors during the growth of ZnCdSeS/ZnS QDs. This strategy leverages nucleophilic reagents bearing uncoordinated lone-pair electrons to stabilize the cationic precursors and modulate the QDs surface energy of highly reactive crystal planes, thereby promoting atomic-scale uniform growth of the QDs, minimizing lattice mismatch, preventing stacking faults, and thus enabling the synthesis of strain-graded QDs (sg-QDs). Consequently, by achieving precise control over both elemental distribution and lattice ordering in multicomponent alloy QDs, sg-QDs are obtained that exhibit a photoluminescence quantum yield of 98% in solution and 95% in the solid film. The sg-QD films further demonstrate monoexponential decay kinetics and reduced defect density, confirming effective trap-state suppression. The resultant green QLEDs achieve a record external quantum efficiency (EQE) of 25.2%, an operational lifetime of 1 925 900 h, and sustained EQE over 20% across a luminance range of 10²–10⁵ cd m⁻². This nucleophile-coordination paradigm redefines the synthesis of alloy nanocrystals, providing a dual-advantage platform for ultrastable optoelectronics and scalable QLEDs manufacturing.

Circularly polarized luminescence (CPL) materials have gained increasing attention for their potential in advanced photonic and chiroptical technologies. Among them, AIE-CPL-LC materials integrating aggregation-induced emission (AIE) with liquid crystalline (LC) order represent a distinctive class of CPL materials. These materials not only exhibit strong emission in the condensed phase but also demonstrate efficient chirality transfer and a remarkable amplification effect of chiral signals. This review summarizes recent advances in the design, assembly, and functional modulation of AIE-CPL-LC materials. A key feature is the significant enhancement of luminescence dissymmetry factor (g_lum) achieved by the self-assembled ordering of mesogens while maintaining strong AIE performance. This enhancement arises from the chiral amplification effect driven by the ordered mesogenic structures, which extend chiral organization from the nanoscale to mesoscopic or even macroscopic levels through helical superstructures. Such hierarchical chirality amplification enhances g_lum by orders of magnitude, thereby improving the CPL efficiency. The intrinsic asymmetry of chiral mesogenic structures may also contribute to CPL activity. Special emphasis is placed on elucidating structure-property relationships, particularly the influence of mesophase type, molecular alignment, and external stimuli on g_lum and the photoluminescence quantum yield. AIE-CPL-LC materials offer a versatile and powerful foundation for the next-generation chiral photonic devices development.

Mechanoluminescent (ML) materials directly convert mechanical stimuli, such as friction and compression, into light without an external power source. In this study, CaZnOS:Mn²⁺, Bi³⁺ phosphors are embedded into two epoxy matrices (Loctite E-30CL and E-51) to create ML composite cylinders, enabling a systematic comparison of matrix effects under end-face rotational sliding and Hertzian line-contact compression. Initially, the effective Young's modulus and Poisson's ratio of the composites are predicted using a simplified scalar form of the Mori–Tanaka micromechanics model and validated these predictions with representative-volume-element finite-element simulations. The derived mechanical parameters are then incorporated into contact-mechanics formulations and ANSYS simulations to determine the stress fields under Hertzian loading. Based on Hertz theory, a quantitative stress–luminescence model is developed that explains why the higher-modulus matrix (E-51) induces stronger stress concentrations and, consequently, higher ML intensity. Experimental results demonstrate that E-51-based composites produce greater light output under both frictional and compressive loading and that increasing the ML particle volume fraction further improves composite stiffness and ML sensitivity. Overall, an integrated theoretical–numerical–experimental framework for force–light coupling is presented, enabling performance prediction and device optimisation of ML composites.

Oxyfluoride glass-ceramics (GCs) containing LaF₃ or α-NaLuF₄ nanocrystals, co-doped with 2 mol% Yb³⁺ and 0.5 mol% Er³⁺, are considered as core materials for the implementation of optical fiber photoluminescence (PL) thermometers. A dual-channel ratiometric thermometry approach combining green (UC, ²H_11/2 → ⁴I_15/2 vs ⁴S_3/2 → ⁴I_15/2) and infrared (IR, ⁴I_13/2(m´) → ⁴I_15/2 vs ⁴I_13/2(m) → ⁴I_15/2) emissions allows the extension of the sensing temperature range above the UC luminescence quenching (at ≈ 650 K) by over 100 K (LaF₃) or 150 K (α-NaLuF₄). The IR channel operates at the wavelength of minimum propagation losses of optical fibers, facilitating long-distance propagation of luminescence signals. The UC channel in LaF₃-GC shows a maximum absolute sensitivity S_A = 102 × 10⁻⁴ K⁻¹ at 602 K in glass and S_A = 71 × 10⁻⁴ K⁻¹ at 591 K in GC with thermal resolution δ = 1.5–3 K. The α-NaLuF₄-glass and -GC reach UC S_A = 90 × 10⁻⁴ K⁻¹ at 698 K. The IR channel in both GCs, based on PL intensity ratios at λ = 1498 nm and λ = 1610 nm, exhibits S_A ≈ 30-10 × 10⁻⁴ K⁻¹ for the 300–800 K range with thermal resolution δ = 4.8-6.4 K.