Advanced Optical Materials最新文献

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.

Short-wave infrared (SWIR) organic photodetectors (OPDs) are promising alternatives to their inorganic counterparts due to their flexibility, low cost, and spectral tunability. However, strong photothermal effects and high integration density in electronics lead to considerable heat generation and device degradation. This study presents high-performance SWIR phototransistors based on a ternary organic comprising PDVT-10 and TMBP-F2TCNQ cocrystal (TF2P). The devices achieve a responsivity of 548 A W⁻¹ and detectivity of 6.8 × 10¹² Jones at 1060 nm, with a broad spectral response (1000–1800 nm) and high hole mobility (1.89 cm² V⁻¹ s⁻¹). A key innovation is the bidirectional doping mechanism, where reciprocal charge transfer enhances carrier density and transport through optimized π–π stacking and interface dipoles. Ultrafast spectroscopy confirms a hole transfer time of 350 fs and more than fourfold mobility improvement compared to PDVT-10 alone. Notably, the device maintains performance over 25–100 °C, with only a 25% drop in responsivity at 70 °C, demonstrating superior thermal stability. While mobility increases with temperature due to thermal activation, photoresponse declines, indicating that the cocrystal is sensitive to heat-induced structural disorder. Significantly, this work offers a viable pathway for developing flexible, high-sensitivity, and thermally stable SWIR OPDs for industrial use.

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.

The anti-ambipolar transistors based on van der Waals (vdW) heterojunctions, constructed from 2D materials, exhibit a variety of tunable physical properties, providing a versatile platform for the exploration of novel physical phenomena and the development of diverse electronic and optoelectronic device functions. Herein, this work presents MoS₂/Ta₂NiSe₅/WSe₂ vdW heterojunctions with significant antiambipolar characteristics, achieving a peak-to-valley ratio as high as 2.04 × 10³, attributed to the synergistic effect of gate modulation on the MoS₂/Ta₂NiSe₅ and Ta₂NiSe₅/WSe₂ vdW heterojunctions. The MoS₂/Ta₂NiSe₅/WSe₂ device implements a ternary inverter by the first Simulation Program with Integrated Circuit Emphasis model. The device also exhibits high-performance photodetection under 532 nm illumination via the photogating effect, with performance metrics including responsivity (R) of 342.5 A W⁻¹ and specific detectivity (D^*) of 9.17 × 10¹² cm Hz^1/2 W⁻¹. Additionally, the heterojunction with two built-in electric fields in the same direction via the photovoltaic effect can be used as self-powered photodetectors, with a R of 392 mA W⁻¹ and a D^* of 5.1 × 10¹² cm Hz^1/2 W⁻¹. And MoS₂/Ta₂NiSe₅/WSe₂ vdW photodetector is applied in the field of optical communication. This work not only achieves a multifunctional phototransistor with excellent electronic and optoelectronic performance but also demonstrates its significant potential in future “All-in-one” chip applications.

Lead sulfide (PbS) colloidal quantum dots (CQDs) have emerged as promising materials for near-infrared (NIR) and short wavelength infrared photodetection, owing to their cost-effectiveness in production, and broadband absorption extending up to 1550 nm. This spectral range provides significant advantages for applications such as autonomous driving. However, the performance of PbS CQD-based devices has been limited by their high leakage currents, especially under reverse bias, which limits detectivity and operational bandwidth. In this work, an innovative device architecture is proposed to substantially reduce dark current densities over a wide reverse bias voltage range. This approach integrates a multi-barrier structure with interlayered polymer charge-blocking layers within the CQD film, effectively suppressing leakage current and preventing breakdown under reverse bias. The CQD/polymer hybrid devices exhibit dark current densities as low as 2 × 10⁻⁵ mA cm⁻² under applied bias up to 5 V, and detectivity exceeding 6 × 10¹² Jones is consistently achieved between 3.5 and 6 V. This architecture also enables efficient field-assisted charge extraction, leading to enhanced bandwidth reaching 660 kHz, far surpassing conventional CQD-only devices. These results demonstrate a viable strategy to overcome the long-standing trade-off between detectivity and speed in NIR CQD photodetectors.

Chirality-induced spin selectivity (CISS) enables spin-polarized charge transport through chiral media without magnetic fields. While extensively studied in organic and biomolecular systems, CISS in semiconductors remains limited, lacking standardized methodologies and mechanistic understanding. II-VI and III-V semiconductor nanocrystals (NCs), with tunable band gaps, high optical quality, strong spin-orbit coupling (SOC) and diverse morphologies, provide an ideal platform for exploring spin-dependent phenomena. This review highlights fundamental concepts of chirality and its manifestation in nanostructures, distinguishing ligand-induced and intrinsic chirality in NCs. This work critically integrates recent advances on the microscopic link between chirality and spin selectivity, emphasizing mechanisms such as exciton-ligand hybridization, and surface/bulk inversion asymmetries that generate Rashba/Dresselhaus effects, leading to interfacial spin-filtering. This work describes structural control and chiroptical properties of chiral II-VI/III-V NCs, discussing factors like morphology, surface defects, and ligand chemistry, while outlining trade-offs among SOC, optical quality, and device integration. Mechanistic models, including exciton-ligand hybridization and photonic coupling, explain trends in circular dichroism. Strategies for tuning spin injection, transport, and relaxation are outlined, emphasizing SOC, structural anisotropy, and compositional engineering. This work assesses challenges in integrating chiral NCs into practical devices – including stability, scalability, environmental safety – and highlight opportunities in spin-LEDs, quantum computation, biosensing, and memory devices.

The design, fabrication, and comprehensive characterization of hole-doped Ge-rich SiGe parabolic quantum wells engineered to exhibit intersubband transitions in the mid-infrared spectral range around 120 meV are reported. The heterostructures are grown on Si substrates by low-energy plasma-enhanced chemical vapor deposition, enabling finely controlled compositional profiles and high crystalline quality. Thorough structural analysis confirms the formation of parabolic potential wells despite the presence of entropic interdiffusion. Photoreflectance spectroscopy is employed to investigate interband optical transitions in these heterostructures, whereas intersubband transitions are studied by Fourier-transform infrared spectroscopy that revealed characteristic constant-energy TM-polarized absorption features up to room temperature. At higher doping levels, a more structured spectral response is observed due to valence-band non-parabolicity. Tight-binding band structure simulations, incorporating many-body effects, accurately reproduce the observed spectral features. These results highlight the potential of SiGe parabolic quantum wells as a versatile and scalable platform for the development of Si-compatible mid-infrared optoelectronic devices based on intersubband transitions.

Light-matter strong coupling generates polariton states, which not only are the subject of fundamental physics studies but may also enable transformative technologies in lasing, optical switching, and chemistry. The exciton polaritons of semiconductors and molecules have been extensively studied. Here, we study the strong light-matter interaction of magic-size nanoclusters (MSCs), which can be considered as extremely confined nanocrystals that bridge the gap between semiconductors and small molecules. It is found that Cd₃P₂ MSCs, with superior size monodispersity and large oscillator strength, enable room-temperature strong coupling in a tunable Fabry–Pérot microcavity, with the Rabi splitting reaching 160 meV. Importantly, the derived transition dipole moment of Cd₃P₂ MSCs is consistent with that obtained from optical Stark effect measurements. The four orders-of-magnitude difference in electric field strength, however, highlights the essence of collective strong coupling in a microcavity in comparison to coupling with the light field in laser pulses.