Advanced Optical Materials最新文献

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.

Hybridized local and charge transfer (HLCT) emitters are gaining attention as a promising class of high-efficiency emitters for organic light-emitting diodes (OLEDs) due to their efficient hot-exciton utilization and tuneable emission properties. However, a comprehensive understanding of the excited-state dynamics remains limited. To replenish this lacuna, three donor-π-acceptor (D-π-A) molecules having moderate twist angles (θ), with acronyms, TSBP, TBPS, and 2TBPS, comprising a triphenylamine (TPA) donor and a thiophene-modified benzophenone acceptor, are designed. These emitters exhibit high photoluminescence quantum yields (PLQYs) in solution and solid states, with TSBP achieving an exceptionally high PLQY of 94% in toluene, 40% in neat film, and 85% in polymethyl methacrylate (PMMA) film. Solvent-dependent photophysics, femtosecond transient absorption spectroscopy and theoretical investigations confirm the formation of the HLCT states in low and moderately polar environment. Utilizing a simple solution-processable method, OLED devices are fabricated with emitters exhibiting green and cyan-blue emission in non-doped and doped conditions respectively. Among them, TSBP delivers an outstanding device performance, achieving an external quantum efficiency (EQE_max) of 4.1% in a non-doped device (CIE: 0.28, 0.62) and a higher EQE_max of 5.6% (CIE: 0.20, 0.55) (CIE = Commission Internationale de l'Éclairage) in a CBP-doped device. These findings underscore the potential of HLCT-based emitters for developing efficient and cost-effective OLEDs.

Nonvolatile metasurfaces capable of multifunctional integration are crucial for increasing the integration density and information capacity of photonic systems. However, most existing integrated devices are volatile and require continuous external energy to maintain their functional states, which limits their further application. Here, one switchable metalens/focusing optical vortex (FOV) generator and two switchable metalenses/superposed FOV generators are designed, fabricated, and experimentally characterized. These devices achieve stable switching between two distinct optical functions through optical or thermal actuation. The first function, operating as a metalens, achieves high-efficiency beam focusing capabilities, which are critical for applications in imaging, sensing, and compact optical systems. The second function generates FOV or superposed FOV beams, offering freedom for spatial mode multiplexing and enhanced physical-layer security in optical communications. By heterogeneously integrating the nonvolatile phase-change material Ge₂Sb₂Te₅ (GST), the silicon-based metasurface devices exhibit stable optical response characteristics. The study of such heterogeneously integrated metasurfaces provides a new pathway for the development of high-performance terahertz (THz) integrated photonic devices.

The identification of lattice sites emission centers in hexagonal CsCdCl₃ perovskite is still challenging. Herein, Zn²⁺ dopant having the d¹⁰ outer electron configuration, effectively eliminated interference from typical dopants’ electron transitions. The Zn²⁺-doped hexagonal CsCdCl₃ is synthesized via precipitation method, while the cubic phase is prepared through grinding method in contrast. The hexagonal phase exhibits a coordination polyhedron-selective dual emission: yellow-green self-trapped excitons (STEs) emission from [ZnCl₆]⁴⁻ octahedra soft-lattice and orange STEs emission from corners-sharing [CdZnCl₉]⁵⁻ dimer. The similar yellow-green STEs emission in cubic phase further confirms the dominant role of [ZnCl₆]⁴⁻ octahedra to promote strong electron-phonon coupling. The photoluminescence quantum yields (PLQYs) of Zn²⁺-doped hexagonal and cubic CsCdCl₃ reached 83.4% and 67.3%, respectively. Density functional theory calculations suggest that the corners-sharing [CdZnCl₉]⁵⁻ dimer mediated exciton transport channel between CBM and CBM+1 band of anti-thermal quenching (ATQ) process and the ligand-to-metal charge transfer (LMCT) transitions occurred from Cl⁻(p)→Cd²⁺/Zn²⁺(s). Moreover, Zn²⁺-doped hexagonal CsCdCl₃ demonstrates encouraging X-ray scintillation performance, achieving a high light yield of 83 700 photons MeV⁻¹ and an ultra-low detection limit of 52.3 nGy_air s⁻¹. This work not only demonstrates a potential X-ray scintillator but also offers a broadened perspective into the excitons’ recombination mechanism in doped perovskite.

Optical integrators are receiving much attention for the monitoring and tracking of exposure conditions of materials to enhance their quality and safety, and to reduce waste. Currently, there is no fluorescent material that can simultaneously track mechanical and thermal histories, which is key to predicting failure modes of materials, and offer programmable response selectivity and sensitivity that provides on-demand tailorability to various applications. Here, a fluorescent sensor that can simultaneously detect strain and thermal history whilst exhibiting memorability is reported. This optical integrator consists of binary droplets containing fluorescent donors and acceptors, respectively. The fluorescent coating showcases an optical-time response via Förster resonance energy transfer (FRET) in which the exchange of fluorophores among binary droplets over time leads to a decrease in the average intermolecular distance between a donor–acceptor pair. The irreversible thermochromic response can be programmed by both the construction of the coating and the concentration of the dye-doped liquid crystal (LC) droplets. The fluorescent coating can further be utilized as a strain sensor. The programmable mechanochromic response depends on the duration and degree of strain. The integrator provides an interface that enables visual detection of both the strain and temperature history of materials.

Visible-light-excited room-temperature phosphorescence (RTP) materials possess significant potential for various practical applications, especially for biological and life related fields. However, developing highly simplified and easily accessible RTP materials that can be activated by visible light remains a significant challenge. Herein, a facile one-step oxidative strategy is reported to directly convert unsubstituted phenothiazine molecule into a self-assembled supramolecular architecture, which exhibits highly efficient RTP with an impressively long lifetime of 305 ms and a phosphorescence quantum yield of 2.0%. The resulting supramolecular framework based on single-component molecular crystal can be formed via abundant hydrogen bonds and π···π interactions. These intermolecular forces construct a rigid 3D network that effectively confine molecular motion, which not only promotes intermolecular electronic coupling and increases the concentration of triplet excitons but also suppresses nonradiative decay pathways of triplet excitons. These factors collectively induce the redshifted absorption and enable visible-light-excited RTP in the extremely simple supermolecules. Given these features, it is successfully applied in multi-level data encryption and decryption. This work provides a promising strategy for the development of single-component RTP materials under visible excitation.

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.

The rapid advancement of near-infrared (NIR) laser applications has created an urgent demand for optical filters that simultaneously achieve decorative coloration, mechanical robustness, and high transmission at laser wavelengths. In this work, a 7-layer Si₃N₄/Si alternating multilayer structure is fabricated on colored glass using magnetron sputtering technology. The optimized photonic structure exhibits specular RGB colors while maintaining exceptional transmittance (>90%) at the NIR laser wavelengths of 930–940 nm, with the total thickness in the order of 500 nm. This unique optical performance originates from precisely engineered admittance matching within the Si₃N₄/Si multilayer architecture. Moreover, the Si₃N₄-dominated framework demonstrates outstanding mechanical durability and scratch resistance owing to its inherent high hardness. By integrating color performance, NIR transmission, and mechanical protection into a single device, the proposed design not only addresses key functional requirements but also provides an advanced solution for applications in laser display, NIR sensing/monitoring, and optical anti-counterfeiting.