Advanced Optical Materials最新文献

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.

Plasmonic resonances offer a powerful way for confining light and amplify interactions at materials interfaces. Among them, Tamm plasmons that arise at the interface between a metal film and a photonic crystal are particularly attractive because they can be excited at normal incidence and support strong field localization. In the specific case of porous or corrugated metal layers, the resonance field can extend to the metal/air interface, where it becomes accessible to overlying materials. Here, a Tamm plasmon device (TD) is introduced fabricated by depositing a corrugated silver layer on a SiO₂/TiO₂ mesoporous distributed Bragg reflector, and tuned to support a Tamm plasmon resonance at 575 nm to enhance light–matter interaction at the bioelectronic interface to maximize cell photostimulation. The TD enhances polymer absorption, influences emission and photothermal response. When interfaced with living cells, this translates into efficient light-driven depolarization at reduced excitation intensity. By concentrating evanescent fields at the polymer interface and acting as an asymmetrical open resonant cavity, the TD architecture markedly lowers the optical energy threshold for cell photostimulation. This versatile platform offers new opportunities for low-power photothermal therapies, neuromodulation, and advanced optoelectronic applications.

Persistent Luminescent Materials

Frequency-domain analysis is used to study afterglow, enabling the direct measurement of charge trapping rates in persistent luminescent materials. This method offers new insights into trapping efficiency and performance, surpassing traditional time-domain techniques and promoting rational material optimization. More details can be found in the Research Article by Manuel Romero, Gabriel Lozano, and co-workers (DOI: 10.1002/adom.202501847).

Circularly Polarized Light

Based on the chiral structure of hydroxypropyl cellulose, chiral photonic films and multi-wavelength circularly polarized fluorescence films are prepared, resulting in functional multi-color arrays for advanced photonic applications. This study promoting the application of cellulose materials in structural color coatings, chiroptical devices, and advanced displays. More details can be found in the Research Article by Mingcong Xu, Shouxin Liu, Wei Li and co-workers (DOI: 10.1002/adom.202501959).

Terahertz (THz) radiation is a powerful probe of low-energy excitations in all phases of matter. However, it remains a challenge to find materials that efficiently generate THz radiation in a broad range of frequencies following optical excitation. Here, we investigate a pyroelectric material, ZnSnN₂, and find that its above-band-gap excitation results in the efficient formation of an ultrafast photocurrent generating THz radiation. The resulting THz electric field spans a frequency range from below 1 THz to above 30 THz. The results suggest that the photocurrent is primarily driven by an ultrafast pyroelectric effect where the photo-excited carriers screen the spontaneous electric polarization of ZnSnN₂. Strong structural disorder reduces the photocarrier lifetime significantly and, thus, enables broadband operation. ZnSnN₂ shows a similar THz-emitter performance as the best spintronic THz emitters regarding bandwidth and amplitude. The study unveils the large potential of pyroelectric materials as efficient and broadband THz emitters with built-in bias fields.

Lead halide perovskites are promising next-generation optoelectronic materials due to their solution processability, tunable bandgap and excellent photoelectric properties. However, achieving deep-blue emission in all-inorganic CsPbX₃ nanocrystals remains challenging due to phase separation, halide volatilization and insufficient stability, limiting industrial application. Herein, a collaborative strategy of “chlorine source regulation—defect passivation—fiber integration” is proposed. By incorporating β-cyclodextrin chloride (βCD-Cl) into CsPbBr₃, we synthesized large-scale deep-blue CsPbBr_3-xCl_x@βCD-Cl microcrystals via a mechanosynthesis route. Flexible blue-light fiber films are fabricated via electrospinning, showing a photoluminescence quantum yield (PLQY) of 55.79% and excellent environmental stability, with only a 16 nm red shift observed after 171 days in water. Additionally, the fiber films enable near-infrared (750 nm)-to-blue photon upconversion (450-490 nm), achieving unprecedented bilirubin degradation efficiency (40% within 20 min). They can serve as core components for next-generation phototherapeutic blankets, combining spectral selectivity (blocking harmful radiation < 420 nm) with therapeutic light transmission, eliminating neonatal retinal phototoxicity risks without requiring protective eyewear. The full solution-processed white-light fiber film is prepared, with CIE coordinates (x = 0.32, y = 0.34) near the ideal white light point. Overall, this study clarifies the molecular structure—performance relationships, overcomes stability bottlenecks, and supports photodynamic therapy and bio-photonic devices.

Cholesteric liquid crystal elastomers (CLCEs) have attracted significant attention for their ability to rapidly modulate structural colors in response to external stimuli. However, their practical applications have been constrained by a limited wavelength tuning range, typically below 160 nm. To address this limitation, a reactive mesogen containing a monoacrylate group is employed to engineer CLCEs with enhanced wavelength tunability. Incorporating the monoacrylate reactive mesogens into the elastomer network effectively reduced the crosslink density, which in turn facilitated a broadband peak shift of up to 430 nm under 200% uniaxial strain. Furthermore, strain-induced broadband camouflage patterning is demonstrated in the CLCE films, thereby highlighting their potential for advanced security applications.

Supercontinuum generation (SCG) with spectral coverage across the full visible and ultraviolet (UV) ranges is crucial for numerous quantum computing and atomic systems. Here, such ultrabroad-bandwidth SCG is demonstrated in low-loss thin-film lithium niobate (TFLN) nanophotonic waveguides fabricated by photolithography-assisted chemo-mechanical etching (PLACE) technique, without additionally introducing complex periodic poling. The MgO-doped waveguides are designed to exhibit anomalous dispersion in the telecom band by tailoring the waveguide thickness, simultaneously enabling dispersive wave emergence, second harmonic, and third harmonic generation to broaden the spectrum. Thanks to the utilization of the strong χ⁽²⁾ and χ⁽³⁾ nonlinear processes in the fabricated low-loss (≈3 dB m⁻¹) waveguide, the SCG with a −80-dB spectral bandwidth as large as 2.7 octaves spanning from 330 to 2250 nm is observed by pumping the waveguide with a 1550-nm femtosecond pulsed laser with 0.687 nJ, agreeing well with numerical simulation. Meanwhile, the SCG sustains its stable spectral envelope for a long period of time thanks to the mitigation of the photorefractive effect of lithium niobate by doping of MgO. And theoretical simulation is carried out to verify the coherence of the fundamental and second harmonic waves.

Despite extensive efforts to self-assemble block copolymers (BCPs) into gyroid photonic crystals, achieving a photonic bandgap (PBG) in the visible regime still remains unreachable due to the difficulty in accessing magnificent lattice sizes. Here, giant BCP gyroids with the largest lateral unit-cell size reported to date (335.7 nm) are successfully assembled and their non-affine lattice structures along with the corresponding photonic band structures are theoretically unveiled. The key to realizing this visible PBG is the precise control of non-affine distortion within the largest gyroid lattices, which effectively transforms their morphology toward a high symmetry state. Particularly, high-molecular-weight polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) films are utilized as templates to construct the giant gyroid. The PMMA-removed, PS gyroid films are treated with cosolvent mixtures of tetrahydrofuran and acetic acid to induce a directional contraction along the z-direction, thereby leading to precise fine-tuning of non-affine distortion. Numerical reconstructions of the resulting gyroid lattices revealed that increasing symmetry through non-affine transformation is critical for opening and widening the PBG in the visible regime. By integrating theoretical modeling with experimental validation of a distinct visible PBG, this study fully uncovers the atlas of giant BCP gyroid structures and their PBG characteristics, which had previously remained elusive.