Light Energy Research Articles

From light into shadow: comparative plastomes in Petrocosmea and implications for low light adaptation

BackgroundPlastids originated from an ancient endosymbiotic event and evolved into the photosynthetic organelles in plant cells. They absorb light energy and carbon dioxide, converting them into chemical energy and oxygen, which are crucial for plant development and adaptation. However, little is known about the plastid genome to light adaptation. Petrocosmea, a member of the Gesneriaceae family, comprises approximately 70 species with diverse light environment, serve as an ideal subject for studying plastomes adapt to light.ResultsIn this study, we selected ten representative species of Petrocosmea from diverse light environments, assembled their plastid genomes, and conducted a comparative genomic analysis. We found that the plastid genome of Petrocosmea is highly conserved in both structure and gene content. The phylogenetic relationships reconstructed based on the plastid genes were divided into five clades, which is consistent with the results of previous studies. The vast majority of plastid protein-coding genes were under purifying selection, with only the rps8 and rps16 genes identified under positive selection in different light environments. Notably, significant differences of evolutionary rate were observed in NADH dehydrogenase, ATPase ribosome, and RNA polymerase between Clade A and the other clades. Additionally, we identified ycf1 and several intergenic regions (trnH-psbA, trnK-rps16, rpoB-trnC, petA-psbJ, ccsA-trnL, rps16-trnQ, and trnS-trnG) as candidate barcodes for this emerging ornamental horticulture.ConclusionWe newly assembled ten plastid genomes of Petrocosmea and identified several hypervariable regions, providing genetic resources and candidate markers for this promising emerging ornamental horticulture. Furthermore, our study suggested that rps8 and rps16 were under positive selection and that the evolutionary patterns of NADH dehydrogenase, ATPase ribosome, and RNA polymerase were related to the diversity light environment in Petrocosmea. This revealed an evolutionary scenario for light adaptation of the plastid genome in plants.

In situ thermal-assisted photocatalytic decarboxylation of high-concentration biomass-derived fatty acids to alkanes

Heating is a straightforward method to increase reaction rates to meet industrial production, yet photocatalysis seldom incorporates it because their intrinsic driving force depends on the separation of photogenerated carriers, which is rarely affected by temperature. Here, we report a temperature-dependent photocatalytic decarboxylation strategy for producing long-chain n-alkanes from biomass-derived fatty acids using only the photothermal effect of the SnS catalyst. Under concentrated light irradiation without any external heating, and by employing high boiling-point solvents to reach optimal reaction temperatures (∼254 °C), Cn-1 n-alkane allows a very high concentration output (∼0.5 M for stearic acid to n-heptadecane) in a single operation, which is far beyond the capacity limit of conventional photocatalysis, typically no more than the mM levels. Mechanistic studies suggest that the in-situ heat brings the standing C-chain at low temperature down onto the SnS surface, increasing strain on the C-COO- bonds and facilitating reaction with photo-induced hole-electron pairs. We demonstrate that the majority of the incident light energy, when converted to heat, accelerates the photocatalytic decarboxylation.

Photomechanical Crystals as Light-Activated Organic Soft Microrobots.

In the field of materials science, dynamic molecular crystals have attracted significant attention as a novel class of energy-transducing materials. However, their development into becoming fully functional actuators remains somewhat limited. This study focuses on one family of dynamic crystalline materials and delves into exploring the efficiency of conversion of light energy to mechanical work. A simple setup is designed to determine a set of performance indices of anthracene-based crystals as an exemplary class of dynamic molecular crystals. The ability of these crystals to reversibly bend due to dimerization is realistically assessed from the perspective of the envisaged soft robotics applications, where wireless photomechanical grippers manipulate and assemble microscopic objects driven and controlled by light instead of lines and motors. The approach described here not only guides the quantification of responsive molecular crystals' actuation potential but also aims to attract an interdisciplinary interest to further develop this class of materials into controllable all-organic actuating elements to be used in microrobotics for engineering or biomedicine.

Bionic Leaf: Ultrahigh energy efficiency in a defect Engineered MoS2 based photo induced charging of flexible Zn-Air battery

Introducing solar energy directly into flexible energy storage systems is an environmentally friendly, efficient, and low-cost strategy. Herein, we constructed a photoelectrode based on flexible carbon cloth (CC) to promote the oxygen evolution reaction (OER) and effectively reduce the charging voltage of flexible zinc-air batteries (ZABs), inspired by the photosynthesis process in leaves. The implementation of sulfur vacancies (VS) and oxygen doping in nanoscale molybdenum disulfide (MoS2) effectively enhances the separation efficiency of photo-generated electron-hole pairs, and adjusts its band structure to improve the oxidation capability. The constructed photocathode with defect-rich MoS2 (D-MoS2) exhibits a low overpotential of 235 mV at 10 mA cm−2 for OER. The sandwich flexible ZABs based on D-MoS2 achieve a low charge voltage around 1.3 V and an ultra-high energy efficiency greater than 90 % under illumination at 0.1 mA cm−2. This strategy provides a new insight for the application of light energy in smart wearable energy storage devices.

Electromagnetic Interference Shielding Films: Structure Design and Prospects.

The popularity of portable and wearable flexible electronic devices, coupled with the rapid advancements in military field, requires electromagnetic interference (EMI) shielding materials with lightweight, thin, and flexible characteristics, which are incomparable for traditional EMI shielding materials. The film materials can fulfill the above requirements, making them among the most promising EMI shielding materials for next-generation electronic devices. Meticulously controlling structure of composite film materials while optimizing the electromagnetic parameters of the constructed components can effectively dissipate and transform electromagnetic wave energy. Herein, the review systematically outlines high-performance EMI shielding composite films through structural design strategies, including homogeneous structure, layered structure, and porous structure. The attenuation mechanism of EMI shielding materials and the evaluation (Schelkunoff theory and calculation theory) of EMI shielding performance are introduced in detail. Moreover, the effect of structure attributes and electromagnetic properties of composite films on the EMI shielding performance is analyzed, while summarizing design criteria and elucidating the relevant EMI shielding mechanism. Finally, the future challenges and potential application prospects of EMI shielding composite films are prospected. This review provides crucial guidance for the construction of advanced EMI shielding films tailored for highly customized and personalized electronic devices in the future.

A simple model of magnetic universe without singularity associated with a quadratic equation of state

A model of magnetic universe based on nonlinear electrodynamics has been introduced by Kruglov (Phys Rev D 92:123523, 2015). This model describes an early inflation era followed by a radiation era. We show that this model is related to the model of universe based on a quadratic equation of state introduced in our previous paper (Chavanis in Universe 1:357, 2015). This correspondence may provide a more fundamental justification of our equation of state. It may arise from quantum corrections to linear electrodynamics when the electromagnetic field becomes very high. We discuss two quantitatively different models of early universe. In Model I, the primordial density of the universe is identified with the Planck density. At t=0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$t=0$$\\end{document}, the universe had the characteristics of a Planck black hole (“planckion” particle). During the inflation, which takes place on a Planck timescale, the size of the universe evolves from the Planck length to a size comparable to the Compton wavelength of the neutrino. If we interpret the radius of the universe at the end of the inflation (neutrino’s Compton wavelength) as a minimum length related to quantum gravity and use Zeldovich’s first formula of the vacuum energy, we obtain the correct value of the cosmological constant. In Model II, the primordial density of the universe is identified with the electron density as a consequence of nonlinear electrodynamics. At t=0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$t=0$$\\end{document}, the universe had the characteristics of an electron. This can be viewed as a refinement of the “primeval atom” of Lemaître. During the inflation, which takes place on a gravitoelectronic timescale, the size of the universe evolves from the electron’s classical radius to a size comparable to the size of a dark energy star of the stellar mass. If we interpret the radius of the universe at the beginning of the inflation (electron’s classical radius) as a minimum length related to quantum gravity and use Zeldovich’s second formula of the vacuum energy, we obtain the correct value of the cosmological constant. This provides an accurate form of Eddington’s relation between the cosmological constant and the mass of the electron. We use these arguments to show that the present universe contains about 1080\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$10^{80}$$\\end{document} protons (Eddington’s number). We also introduce a nonlinear electromagnetic Lagrangian that describes simultaneously the early inflation, the radiation era, and the dark energy era. It may account for a form of “generalized radiation” that is present from the beginning to the end of the cosmic evolution. Baryonic and dark matter are treated as independent noninteracting species. The dark energy era is due to the electromagnetic vacuum energy (zero-point radiation). In this approach, both the early inflation and the late acceleration of the universe (dark energy) arise as a consequence of nonlinear electrodynamics. This leads to a simple model of magnetic universe without singularity (aioniotic universe).

Unravelling the Enigmatic Nexus: Black Holes, Dark Matter, and the Interplay of Light, Gravity, and Electromagnetic Forces in Astrophysics and Astronomy

This research introduces a mathematical model positioning our physical reality within a ten-dimensional hyperspace, in which time acts as the unifying coordinate linking three-dimensional electric, magnetic, and gravitational spaces. Each domain is characterized by its respective field—electric, magnetic, or gravitational—and governed by intrinsic divergences and rotations, leading to a universal property known as Force Density, expressed in [N/m³]. This Force Density facilitates interactions among the distinct spaces while adhering to the principle of equilibrium, which posits that cumulative force densities from disturbances must consistently sum to zero. Building upon Einstein's General Relativity—which describes the curvature of spacetime by gravitational fields and assumes a constant light speed—this study proposes a perspective wherein light speed may vary during coherent laser beam interactions, prompting a re-examination of gravitational and luminous interactions across scales. The proposed model integrates the Stress-Energy Tensor and Gravitational Tensor, introducing a new tensor representation for black holes, termed Gravitational Electromagnetic Confinements, incorporating electromagnetic energy gradients and Lorentz transformations. This framework transcends traditional General Relativity, particularly evident in gravitational lensing. By reinterpreting Einstein's incorporation of the Gravitational Constant within the Energy-Stress Tensor, this work harmonizes gravity and light, offering insights into black hole solutions resonating with John Archibald Wheeler's 1955 research. Empirical data from Galileo satellites and MASER frequency measurements underscore discrepancies between established theories and this new model, enhancing the precision of gravitational observations. Through the confluence of Quantum Physics and General Relativity, as seen in approaches like String Theory, this interdisciplinary endeavor revisits the gravitational constant "G," redefining it while bridging theoretical frameworks, thus paving the way for breakthroughs in astronomical and astrophysical sciences.

Performance of yellow and pink oyster mushroom dyes in dye sensitized solar cell

A solar photovoltaic (PV) cell, is an electrical device that uses the PV effect to convert light energy into electricity. The application of oyster mushroom dyes in dye sensitized solar cell (DSSC) is a novel strategy to substitute the costly chemical production process with easily extractable, environmentally acceptable dyes. Both dyes of yellow and pink oyster mushrooms were extracted using the same process but dried into powder form using two techniques, warm drying and freeze drying. The characterization was carried out utilizing current-voltage (I-V) characterization for electrical properties, Ultraviolet-Visible (UV-Vis) spectrophotometer for optical properties, Field Emission Scanning Electron Microscopy (FESEM), and Atomic Force Microscopy (AFM) for the structural properties. It was found that freeze-dried pink and yellow oyster mushroom had shown the good properties for DSSC application as it produced energy bandgap which lies within the range of efficient dye sensitizer; 1.7 eV and 2.2 eV, the most uniform distribution of pores and a nearly spherical form in FESEM analysis, and AFM result obtained with the highest root mean square (RMS) roughness value (26.922 and 34.033) with stereoscopic morphologies. The data proved that mushroom dyes can be incorporated in DSSC with the optimization of drying method in the extraction process, dilution of dye and the layer of deposition on the glass substrate. The current density-voltage (J–V) characteristics of fabricated DSSC was characterized using Newport Oriel Sol3A solar simulator under AM 1.5 Sun condition (100 mW/cm2, 25 oC). From the result obtained by solar simulator, the fabricated FTO/TiO2/Pleurotus djamor dye/Pt indicated the Voc of 0.499 V and Jsc of 0.397 mA/cm2.

Architectural Design of a Multichannel Porous Carbon Fiber for Efficient Electromagnetic Microwave Absorption.

An ingenious microstructure of electromagnetic microwave absorption materials is crucial to achieve strong absorption and a broad bandwidth. Herein, one-dimensional (1D) carbon fibers with implantation of zero-dimensional (0D) ZIF-8-derived carbon frameworks and construction of a three-dimensional (3D) microcosmic multichannel porous structure are fabricated by electro-blown spinning, solvent-thermal reaction, and high-temperature pyrolysis techniques. The 1D carbon fiber skeleton with a multichannel structure provides a direct axial conductive pathway for charge transport, which plays an important role in dielectric loss. The 0D surface carbon frameworks offer plenty of heterogeneous interfaces to trigger intensive interfacial polarization loss and act as dihedral angles for microwave scattering. The 3D microcosmic multichannel pores can not only generate multiple reflections as much as possible to dissipate electromagnetic microwave energy but also supply huge interior cavities to improve impedance matching. Thanks to the synergistic effect of a strong electrically conductive pathway for enhancing the conductive loss, a plenteous heterogeneous interface for triggering intensive interfacial polarization loss, microcosmic multichannel pores for generating multiple reflections and improving impedance matching, and N and O atom doping for inducing dipole polarization, the optimal sample with an ingenious microstructure delivers an excellent absorption performance of a minimum reflection loss of -35.5 dB at a thickness of 5.0 mm and an effective absorption bandwidth of 6.72 GHz (10.96-17.68 GHz) at a thickness of 2.0 mm. Such a well-designed multichannel porous carbon fiber may pave the way for the exploitation of high-performance microwave absorbing materials.

Empirical study of facade retrofits for optimizing energy efficiency and cooling in school buildings in Saudi Arabia

Educational buildings in Saudi Arabia are characterized by high energy consumption, primarily due to cooling and lighting demands. This study aims to evaluate and optimize facade retrofitting strategies to improve energy efficiency and evaluate economic performance of many scenarios in Saudi school buildings, aligning with the sustainability objectives of Saudi Vision 2030. The research employs a simulation-based optimization methodology utilizing Design Builder software to explore key facade design variables, including Window-to-Wall Ratio, glazing type, local shading devices, and external wall insulation. The methodology is structured in sequential stages: it begins with the collection of base-case data, followed by a data-driven optimization process targeting specific design variables. This is then complemented by an economic and environmental assessment of the optimal retrofit scenarios, ultimately leading to the identification of the most effective energy-saving solution presented at the conclusion of the study. Through an optimization process, the research identifies retrofitting strategies that reduce cooling loads by up to 17 %, lighting energy consumption by 49 % and annual energy costs by 18 %. The study also includes an economic analysis of the retrofits, revealing significant savings in annual electricity costs and a reduction in the building's carbon footprint. This research contributes valuable insights into sustainable building practices, offering practical solutions for improving energy efficiency in the educational sector. The novelty of this study lies in its comprehensive analysis of facade retrofits within the context of extreme climatic conditions, which provides a replicable model for retrofitting educational buildings across the region. The findings have significant implications for policymakers, architects, and sustainability advocates seeking to meet Saudi Arabia's energy conservation goals.

Photocatalytic fuel cell based on dual Z-scheme heterojunction photoanode InVO4/g-C3N4/Bi2WO6/Ti for efficient Rhodamine B degradation and power generation

Finding suitable semiconductor materials to construct efficient photoanode is the key to improve PFC performance. In this paper, InVO4/g-C3N4/Bi2WO6/Ti composite photoanode was prepared and assembled with Cu cathode to construct PFC for rhodamine B (RhB) degradation and power generation. The InVO4/g-C3N4/Bi2WO6/Ti photoanode was characterized by XRD, FT-IR, XPS, SEM, TEM, EDS and DRS. The electrochemical properties of the PFC including polarization curves, power density, transient photocurrent, LSV and CV curves were analyzed to explore its power generation and electron transfer mechanism. The results showed that the ternary composite photoanode had stronger light absorption, smaller Eg (1.96 eV) and Rct (0.71 Ω), and higher photocurrent current density (0.16 mA cm−2) than binary and single composite photoanodes, indicating that it had higher utilization rate of excitation light energy and carrier mobility. The RhB degradation rate, Pmax, Jsc and Voc of PFC were 93.1 % (90 min), 18.02 µW cm−2, 0.223 mA cm−2 and 0.44 V, respectively. Further mechanistic studies show that the PFC has good photoexcited carrier separation and strong redox capacity due to double Z-scheme heterojunction between Bi2WO6 and InVO4 and between Bi2WO6 and g-C3N4, so as to generate more O2− and h+ to degrade RhB through N-deethylation, dealkylation and ring opening reactions. This study provides a practical approach for the development of high-efficiency double Z-scheme composite photoanode.

Ground-penetrating radar subsurface attenuation analysis based on a sparsity-promoting time-frequency transform

The attenuation characteristics of a medium involve the absorption of electromagnetic wave energy during its propagation and represent a crucial parameter for describing the properties of subsurface media. Due to the complex nature of signal attenuation, demanding consideration of numerous parameters, quantitative analysis is challenging. Time-frequency (TF) analysis is a promising technique that simultaneously analyzes nonstationary signals in the time and frequency domains. Although the quantitative characterization of attenuation factors using TF tools can be challenging, TF analysis retains substantial potential for qualitatively estimating attenuation from ground-penetrating radar (GPR) data. The sparsity-promoting TF (SPTF) transform method with [Formula: see text] and [Formula: see text] norms joint constraints has a significantly higher TF resolution than the linear TF transform in the time and frequency domains. We develop a method for high-resolution qualitative estimation of GPR attenuation based on the SPTF method. Synthetic experiments indicate that SPTF surpasses other methods regarding TF resolution, noise robustness, and fidelity to dominant frequencies. Subsequent qualitative attenuation results using synthetic and field data agree with synthetic model outcomes and actual leakage ranges. This alignment substantiates the superior resolution and accuracy of our approach compared with alternative methods, affirming its efficacy and superiority in GPR attenuation depiction.

Enhancing Energy Harvesting Efficiency from Ambient Sources through Advanced Materials and Nanotechnology

The utilization of ambient energy sources for powering small-scale electronic devices and sensors has garnered significant attention due to its potential for sustainable and autonomous operation. This research focuses on enhancing the efficiency of energy harvesting from ambient sources, such as vibrations, heat differentials, and electromagnetic fields, through the integration of advanced materials and nanotechnology into energy harvesting systems. The study begins with a comprehensive review of existing energy harvesting technologies, highlighting their limitations in terms of efficiency, scalability, and adaptability to various ambient energy sources. It identifies the key challenges faced in achieving high energy conversion rates and explores the potential of advanced materials and nanoscale structures to address these challenges. One aspect of the research involves the development and characterization of novel materials with superior energy conversion properties. This includes the synthesis of piezoelectric materials for vibration energy harvesting, thermoelectric materials for heat-to-electricity conversion, and nanomaterials for enhancing electromagnetic energy harvesting efficiency. Advanced characterization techniques, such as scanning electron microscopy (SEM) and X-ray diffraction (XRD), are employed to analyze the structural and electrical properties of these materials. Furthermore, the study investigates the design and fabrication of nanostructured energy harvesting devices optimized for specific ambient energy sources. This involves the integration of nanoscale components, such as nanostructured electrodes, into energy harvesting systems to improve energy capture and conversion rates. Finite element analysis (FEA) simulations and experimental testing are conducted to evaluate the performance and efficiency of these nano-enhanced energy harvesting devices under real-world conditions. The research also addresses the optimization of energy harvesting system parameters, including resonance tuning, impedance matching, and energy management circuits, to maximize energy extraction and utilization. Computational modeling techniques, such as multiscale modeling and finite element simulations, are utilized to optimize system configurations and improve overall energy harvesting efficiency. Overall, this research contributes to the advancement of energy harvesting technologies by leveraging advanced materials and nanotechnology, paving the way for sustainable and autonomous power generation from ambient energy sources for a wide range of applications.

Visible Light-Responsive Crystalline B←N Host Adducts with Solvent-Induced Allosteric Effect for Guest Release.

Photo-responsive organic crystals, capable of converting light energy into chemical energy to initiate conformational transitions, present an emerging strategy for developing lightweight and versatile smart materials. However, visible light-triggered tailored guests capture and release behaviors in all-organic solids are rarely reported. Here, we introduce a photoreactive crystalline boron-nitrogen (B←N) host adduct with the ability to undergo [2+2] photocycloaddition upon 447 nm light exposure. This process facilitates single-crystal-to-single-crystal (SCSC) photodimerization in the mother liquor, maintaining the original B←N host structure. Weakened intermolecular interactions within the photodimer host contribute to fast guest release in air under irradiation. Furthermore, the dynamic B←N bonds enable reversible transformations between organic host adducts and adduct cocrystals under the solvent-induced allosteric effect. As a result, four B←N host adduct crystals containing individual alkane guest are easily obtained and exhibited the ability of photo-controlled alkane release. Therefore, the integration of photo reactivity and structural transformation within B←N host adduct enables customized capture and release of guest molecules.

Visible Light‐Responsive Crystalline B←N Host Adducts with Solvent‐Induced Allosteric Effect for Guest Release

AbstractPhoto‐responsive organic crystals, capable of converting light energy into chemical energy to initiate conformational transitions, present an emerging strategy for developing lightweight and versatile smart materials. However, visible light‐triggered tailored guests capture and release behaviors in all‐organic solids are rarely reported. Here, we introduce a photoreactive crystalline boron‐nitrogen (B←N) host adduct with the ability to undergo [2+2] photocycloaddition upon 447 nm light exposure. This process facilitates single‐crystal‐to‐single‐crystal (SCSC) photodimerization in the mother liquor, maintaining the original B←N host structure. Weakened intermolecular interactions within the photodimer host contribute to fast guest release in air under irradiation. Furthermore, the dynamic B←N bonds enable reversible transformations between organic host adducts and adduct cocrystals under the solvent‐induced allosteric effect. As a result, four B←N host adduct crystals containing individual alkane guest are easily obtained and exhibited the ability of photo‐controlled alkane release. Therefore, the integration of photo reactivity and structural transformation within B←N host adduct enables customized capture and release of guest molecules.

Enigmatic factor of 4/3 in electromagnetic momentum of a moving spherical capacitor

The electromagnetic energy–momentum of a moving charged spherical capacitor may be calculated by a 4-vector Lorentz transformation from the energy in the rest frame. However, energy–momentum of the moving system computed directly from electromagnetic fields yields extra terms; in particular a factor of 4/3 in momentum appears, similar to that encountered in the classical electron model, where this enigmatic factor has been a source of confusion for more than a century. There have been many attempts to eliminate this ‘unwanted’ factor, noteworthy among them is a modification in electromagnetic field energy–momentum definition that has entered even standard textbooks. Here it is shown that in a moving charged spherical capacitor, such a factor of 4/3 in the electromagnetic momentum arises naturally from electromagnetic forces in system or equivalently from terms in the Maxwell stress tensor; contributions that do not otherwise show up in 4-vector transformations. A similar factor of 4/3 in the momentum of a perfect fluid comprising a randomly moving ultra-relativistic gas molecules or an isotropic photon gas, filling an uncharged spherical capacitor in motion, appears owing to the contribution of pressure. Thus, genesis of the ‘enigmatic’ factor of 4/3 can be traced to pressure or stress whose presence in the system may even be of non-electromagnetic origin and where the proposed modifications in energy–momentum definition do not even come into picture, implying there is no justification in modifying the standard definition of electromagnetic energy–momentum.

Energy-harvesting tile incorporating an origami coupling mechanism.

We present the design and evaluation of a simple, compact and efficient electromagnetic energy harvesting tile that can be used to harness energy from footsteps. The proposed harvester incorporates a translational-rotational origami-inspired coupling mechanism to transform the axial loads exerted by human footsteps into a localized rotation of an electromagnetic generator. The coupling mechanism employs a non-rigid tunable Kresling spring, the restorative behaviour of which is tunable to maximize energy transduction from the applied load to the generator. A computational model is developed to optimize the design parameters of the mechanism, which are then utilized to fabricate a prototype of the energy harvester. The tile is tested under loading conditions that mimic a human step, where it is demonstrated that it is capable of generating 4.18 W of electrical power per step with a surface power density of 2609 μW cm-2.This article is part of the theme issue 'Origami/Kirigami-inspired structures: from fundamentals to applications'.

Modeling the Dynamic Response of a Light-Driven Liquid Crystal Elastomer Fiber/Baffle/Spring-Coupled System

Abstract A self-oscillating system can harness energy from the external environment to sustain its continuous motion, making it highly suitable for applications in soft robotics, military industry, energy, and other fields. This article introduces a system composed of a light-responsive liquid crystal elastomer fiber, a baffle, and a spring, capable of achieving self-oscillation under stable lighting conditions. Considering the established dynamic model of light-responsive liquid crystal elastomers (LCEs), a nonlinear dynamic model is introduced and used as the basis for exploring its dynamic characteristics. Numerical computations reveal that the coupled system exhibits two distinct motion states: self-oscillation and static states. The behavior of the system is sustained through the interaction of light energy and damping dissipation. Furthermore, a detailed investigation is conducted on the key system parameters affecting the frequency and amplitude of self-oscillation. In contrast to the complexity of current self-oscillating systems, this particular self-oscillating system features simplicity in structure, ease of manufacture, and strong adaptability. These advantages are expected to provide broader design possibilities for micro-machines and mechanical production processes.

Overview of the Design and Application of Photothermal Immunoassays.

Developing powerful immunoassays for sensitive and real-time detection of targets has always been a challenging task. Due to their advantages of direct readout, controllable sensing, and low background interference, photothermal immunoassays have become a type of new technology that can be used for various applications such as disease diagnosis, environmental monitoring, and food safety. By modification with antibodies, photothermal materials can induce temperature changes by converting light energy into heat, thereby reporting specific target recognition events. This article reviews the design and application of photothermal immunoassays based on different photothermal materials, including noble metal nanomaterials, carbon-based nanomaterials, two-dimensional nanomaterials, metal oxide and sulfide nanomaterials, Prussian blue nanoparticles, small organic molecules, polymers, etc. It pays special attention to the role of photothermal materials and the working principle of various immunoassays. Additionally, the challenges and prospects for future development of photothermal immunoassays are briefly discussed.

Near-infrared multi-band small-angle TE-polarization nonreciprocal thermal emitter

Multi-band small-angle irreversible radiation is significantly demanded in applications of high-resolution infrared sensing and infrared filtering. However, current nonreciprocal thermal radiation is either multichannel radiating with large incident angles or radiating at small angles within one single band. To address this issue, a multi-band nonreciprocal thermal emitter operated by exciting multiple resonances within the near-infrared band is proposed. The adopted microstructure arrays consist of periodic silicon square-ring arrays that are supported by magneto-optical medium and metal layer. With the physical mechanisms study through electromagnetic field energy distribution, the TE-polarized multi-band nonreciprocity of thermal radiation is over 70 % at small incident angle of 4°. Equally important, this strategy is effective and generalizable for dual-polarized small-angle multi-band nonreciprocal radiation with adopted microstructure arrays. It is believed that this scheme can promote the development of nonreciprocal thermal photonics.