Advanced Optical Materials最新文献

The dispersion characteristics of nonlinear photocurrent response such as shift current, providing crucial information for understanding the nonlinear optoelectronic properties of semiconductors, yet remains relatively unexplored in a broadband region with non-contact and sensitive experiments. Herein, terahertz (THz) emission spectroscopy is utilized as a wireless and all-optical method to reveal the photon-energy-dependent ultrafast shift current in tin telluride（SnTe ）. The shift current is induced by the bulk photovoltaic effect and further identified by the pump-fluence dependence and light-polarization dependence of THz radiation. Interestingly, the shift-current-dominated THz radiation is enhanced near the bandgap (E_g) and 2E_g excitation due to the resonance in SnTe, and the dispersion of shift current conductivity tensor is unveiled in the energy ranges of 0.5–0.9 eV and 1.2–1.8 eV. This dispersion feature can be well described by the nonlinear anharmonic oscillator model with the high density of states at the resonant positions. These findings provide a fundamental understanding of the dispersion of shift current in experiments and further apply to the development of shift-current based novel THz devices and photovoltaic devices.

Luminescent solar concentrators (LSCs) hold the promise to make solar electricity more affordable by reducing the need for expensive photovoltaic cells and enabling less conventional forms of photovoltaics such as solar windows or roofs, and other architectural elements. Here the use of a polymer of intrinsic microporosity (PIM-1) is demonstrated as an efficient light absorber in an LSC, combined with a red-emitting dye. The prepared prototype LSC displays good internal efficiency (25.3%) and external efficiency (12.6%), and performance metrics that show promise for the use of polymers of intrinsic microporosity as light harvesters. This work significantly broadens the potential applications of PIMs beyond their more traditional functions in molecular separations and other adsorption-based processes.

Chiral Plasmonic Nanoparticles

Strong helical dichroism has been achieved in a chiral plasmonic nanoparticle (helicoid) array (2D helicoid crystal). More details can be found in article 2402268 by Ki Tae Nam, Sejeong Kim, and co-workers.

Laser patterning of perovskite is a novel technology with the advantages of high speed, programmability, and maskless, which is ideal for fabricating micro light-emitting diodes (micro-LED) color conversion layers (CCL). This work reports a method for laser in situ synthesis of wide bandgap tunable perovskite with an emission spectrum from 475 to 667 nm. Based on the photonic effect of continuous wave (CW) laser and the thermal quenching phenomenon of perovskite, ultra-high precision patterning with a minimum linewidth of 750 nm and a maximum dot-pixel per inch (PPI) of 5684 is achieved. More importantly, significant improvements in perovskite stability and integration of red-green dual-color dot arrays are achieved through in-depth studies of polymer matrices and precursor solvents. The red-green dual-color integrated dot arrays using blue micro-LED chips, which is a great impetus to the research of micro-LED full-color displays, are also successfully excited.

2D structural color metasurfaces have emerged as an ideal and sustainable alternative to chemical dyes due to their stability and environment-friendly attributes. In this study, a polarization-manipulated transmissive structural color based on dual complementary nanograting cavities (DC-NGC) is proposed and experimentally validated. The DC-NGC structure is implemented with Ag-covered dielectric nano gratings sitting on a substrate with a thin dielectric and metallic film. It is found that not only strong polarization dependent and wavelength selective transmission occurs in the structure, but also an additional selective absorption under transverse magnetic (TM) incidence for high-order transmission associated with the inherent multiple nanocavity resonant modes. These features make both high design flexibility and a rich color palette with a narrow linewidth possible. Experimental demonstrations are performed by validating the polarization-dependent and wavelength-selective behaviors, fabricating a color palette with varying structural parameters and three different vibrant and colorful patterns showcasing diverse colors under different polarization states. The proposed dual-nanograting-cavity color filter with versatile polarization colors and superior color purity holds significant potential in various applications, including full-color filtering, display, and micro-pattern anti-counterfeiting.

Meta-lenses have advanced focusing and imaging capabilities. Traditional methods for assessing meta-lenses performance, such as focusing light field scanning, are time-consuming and cannot obtain phase information. Meta-lenses require accurate and fast phase information measurements for industrial-level applications. Here, a novel approach is introduced for meta-lenses phase recovery from defocused images. The precise phase can be obtained by optimizing the complex amplitude of the meta-lens from the experimentally collected defocused images through complex gradient descent. This method doesn't need complicated experimental setups like traditional off-axis interferometry. This method is robust and applicable to meta-lenses with diverse phase modulations. The investigation is extended to measure the phase information of the Pancharatnam-Berry phase-based meta-lens and the achromatic meta-lens in different incident wavelengths. These results demonstrate that this technique accurately recovers phase information. The 3D intensity profile can be retrieved at arbitrary distances, which is faster and more accurate, enabling the prediction of optical properties such as focal length. This advancement enhances the understanding of meta-lense behavior in practical scenarios. It provides a foundation for future optimizations in meta-lenses design, potentially leading to more efficient and versatile optical systems.

The field of optical chirality has achieved remarkable progress with the quick development of artificial metasurfaces. The introduction of quasi-bound states in the continuum (QBIC) into chiral devices offers a groundbreaking and efficient method for modulating chiral responses. However, existing QBIC-based chiral research primarily concentrates on dielectric structures and also encounters challenges such as complex design requirements and limitations to single-frequency band operation. In this work, a metallic double-layer twisted metasurface is proposed. By manipulating a single degree of freedom (DOF), the twist angle, QBIC and chirality are simultaneously induced at two frequency bands. Far-field multipole decomposition and near-field analysis reveal that the two QBICs originated from electric dipole and toroidal dipole moments. Experimental spectra highly agree with simulation results, confirming the efficacy of the design. Remarkably, the structure exhibits opposite chiral responses at different frequency bands. To highlight the device's superiority, a dynamic near-field image display switched by frequency or polarization state is demonstrated in simulation. The proposed structure holds potential applications in chiral enantiomer sensing, chiral lasers, nonlinear filtering, and other related areas.

The rapid advancement of optoelectronic devices, particularly photodetectors, demands enhanced sensitivity for detecting weak light. In this study, MAPbI₃-MAPbBr₃ perovskite single crystal heterojunctions (SCHs) are fabricated via atomic force bonding using liquid-phase epitaxy, with polydimethylsiloxane (PDMS) serving as a substrate protector. The resulting SCHs photodetector exhibits self-driven operation, an ultra-low dark current, and a high on-off ratio of 5.8 × 10⁴ at 0 V bias. Under weak illumination and 5 V bias, the device achieves a maximum external quantum efficiency of 414.9%. With a remarkable detection rate of 4.5 × 10¹³ Jones, the device demonstrates outstanding potential for weak light imaging. Furthermore, the self-driven SCHs photodetector enables high-quality imaging under a 445 nm light source at a remarkably low intensity of 2.7 µW cm⁻², without the need for any external power supply.

The ab initio nonadiabatic molecular dynamics (NAMD) approach is advanced by integrating light–matter interactions, enabling comprehensive simulations of the carrier dynamics in solid materials from photoexcitation to relaxation. Using this method, the excited electron and hole dynamics are investigated in monolayer MoSe₂ entangled with optical field, phonons and spin-orbit coupling (SOC), encompassing the dynamics from valley polarization to depolarization. During the initial 0.6 ps after photoexcitation, the optical field dominates, leading to rapid electron valley polarization and a high-polarization plateau, alongside phonon-assisted intervalley photoexcitation. Subsequently, electron-phonon interactions and SOC starts to play a role in the electron depolarization, diminishing polarization to zero around 1.6 ps. Hole polarization is also induced by photoexcitation, and it depolarizes more slowly than electrons without an optical field but becomes dependent on the optical field when laser is present. This work provides a powerful tool for studying the coherent effects of optical fields, phonons, and SOC in photoexcitation dynamics, which is crucial for the design of next-generation optoelectronic devices.

In order to inhibit non-radiative decay pathways of covalent-organic frameworks (COFs), a strategy is proposed to block intralayer conjugation and interlayer π–π stacking by using flexible aggregation-induced emission (AIE) building blocks (4′,4′′′,4′′′′′,4′′′′′′′-(1,2-ethenediylidene) tetrakis[1,1′-biphenyl]-4-carbaldehyde (TFBE)) connected by weakly conjugated flexible linker. By using the flexible TFBE as building blocks and changing the conjugation and flexibility of linker, TFBE-COFs with different luminescence properties are obtained. Experimental and theoretical results show that these TFBE-COFs have high crystallinity and large layer spacing, among which the photoluminescence quantum yield of hydrazone (Hz)-COF_TFBE-ODH (oxalyl dihydrazide (ODH)) in solid state reaches 26.28%, which is superior to most of the COFs reported so far. The excellent luminescence is attributed to the non-planar geometry and flexibility of TFBE, which inhibits aggregation-induced quenching. Moreover, the π-electron delocalization-induced non-radiative leaps are suppressed by weakly conjugated flexible linker, which further enhances the photoluminescence of TFBE-COFs. The Hz-COF_TFBE-ODH exhibits excellent sensing performance for trace tetracycline, the detection limit is 0.15 µm. In addition, a white light-emitting diodes coated with Hz-COF_TFBE-ODH is manufactured to achieve high-quality white light emission. This study provides a new strategy for the design and application of high-emission COFs.