Material Absorption Research Articles

Investigation of luminescence properties of hydrothermally synthesized Pr3+ doped BaLuF5 nanoparticles under excitation by VUV photons

We report on the luminescence properties of hydrothermally synthesized BaLuF5:Pr3+(1%) nanoparticles having a cubic crystal structure. The properties were investigated at low temperatures using time-integrated and time-resolved luminescence spectroscopy under VUV photon excitation in the energy range of 5–45 eV. This spectral region covers both the Pr3+ 4f2→4f15d1 transitions and the intrinsic absorption of the host material. Due to the weak crystal field, only the intra-configurational Pr3+ 4f2→4f2 transitions were observed, resulting in photon cascade emissions. According to structural and morphological studies, the nanoparticles, with an average size of 21 ± 4 nm, were found to possess large amounts of defects, which are further confirmed through luminescence spectroscopy. The influence of non-radiative decay at the surface and energy transfer to the defects are responsible for the shortening of luminescence decay detected for the 1S0 transitions of Pr3+ ions and intrinsic UV cross-luminescence of host materials. We have discussed the specific energy transfer processes that populate various luminescence centers and evaluated BaLuF5:Pr3+(1%) nanoparticles for potential optical applications.

Effects of cyclic ageing frequencies on the ageing and mechanical behaviour of adhesive materials: Experimental analysis and numerical study

In marine structures adhesive joint structures are often exposed to cyclic conditioning where the ambient humidity changes cyclically during their service. Though some comprehensive studies on the aging of adhesives exist, these researches mainly focus on monotonic aging conditions where the adhesive joints are exposed to a wet condition continuously for a long time. However, the few investigations performed on the cyclic moisture absorption of adhesive materials show that the parameters obtained in monotonic aging conditions are not suitable for estimation of the aging behaviour of adhesive exposed to alternating humidity. An important question that can arise is whether or not this frequency affects the mechanical behaviour of adhesive joints under cyclic aging condition. In this investigation bulk dogbone and square samples were manufactured, subjected to cyclic aging conditions with four different aging frequencies and tested. The results show that the moisture diffusion constant of adhesives exposed to higher aging frequencies increase more than those exposed to lower aging frequency conditions. In addition, the moisture content only affects the degradation of strength and stiffness of the tested adhesives in different aging frequencies.

Unraveling synergistic mechanisms of enhanced electrocoagulation sludge dewatering using modified sludge-based biochar

Electrocoagulation (EC) is an environmentally friendly and efficient method that enhances sludge dewatering. However, EC has limited cracking efficiency for extracellular polymeric substances (EPS) and sludge cells. In this study, sludge-based biochar prepared by KOH impregnation (SB-KOH) was added to the EC process as both conductor and skeleton particles of the EC sludge dewatering system. As a result, the current transmission capacity and the “flocculation” effect of sludge were enhanced by SB-KOH. By optimizing the voltage, carbon dosage, specific resistance to filtration (SRF), and capillary suction time (CST0/CST), using enlarged plate area (EFe-EC + SB-KOH) and anode material replacement (Al-EC + SB-KOH), enhanced sludge dewatering performance was achieved. The results showed that SRF and CST0/CST were reduced by 66.29 % and 75.71 %, respectively, when using SB-KOH with optimal EC voltage of 25 V and 15 % dry solid (DS). In addition, the Zeta potential of the system and the sludge particle size were increased, and the surface roughness of flocs was reduced. Three-dimensional fluorescence (3D-EEM) analysis indicated that EC + SB-KOH greatly decomposed aromatic protein-like substances in EPS and led to internal material transfer or absorption. Scanning electron microscopy (SEM) and particle size analysis showed that EC + SB-KOH was beneficial to achieve stronger flocculation and solid-liquid separation performance. The above findings indicate that the efficiency of sludge dewatering was enhanced using SB-KOH self-circulation technology, which provides a validation basis for green and sustainable development.

Surface Engineering of Anodic WO3 Layers by In Situ Doping for Light-Assisted Water Splitting.

This study presents a novel approach to fabricating anodic Co-F-WO3 layers via a single-step electrochemical synthesis, utilizing cobalt fluoride as a dopant source in the electrolyte. The proposed in situ doping technique capitalizes on the high electronegativity of fluorine, ensuring the stability of CoF2 throughout the synthesis process. The nanoporous layer formation, resulting from anodic oxide dissolution in the presence of fluoride ions, is expected to facilitate the effective incorporation of cobalt compounds into the film. The research explores the impact of dopant concentration in the electrolyte, conducting a comprehensive characterization of the resulting materials, including morphology, composition, optical, electrochemical, and photoelectrochemical properties. The successful doping of WO3 was confirmed by energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Raman spectroscopy, photoluminescence measurements, X-ray photoelectron spectroscopy (XPS), and Mott-Schottky analysis. Optical studies reveal lower absorption in Co-doped materials, with a slight shift in band gap energies. Photoelectrochemical (PEC) analysis demonstrates improved PEC activity for Co-doped layers, with the observed shift in photocurrent onset potential attributed to both cobalt and fluoride ions catalytic effects. The study includes an in-depth discussion of the observed phenomena and their implications for applications in solar water splitting, emphasizing the potential of the anodic Co-F-WO3 layers as efficient photoelectrodes. In addition, the research presents a comprehensive exploration of the electrochemical synthesis and characterization of anodic Co-F-WO3, emphasizing their photocatalytic properties for the oxygen evolution reaction (OER). It was found that Co-doped WO3 materials exhibited higher PEC activity, with a maximum 5-fold enhancement compared to pristine materials. Furthermore, the studies demonstrated that these photoanodes can be effectively reused for PEC water-splitting experiments.

Bioinspired multiscale hierarchical structure enables solar-thermal conversion for low-temperature aqueous electrochromic device

Solar-thermal conversion can mitigate the inadequate electrochemical performance in extreme cold environment for aqueous electrochromic devices (AEDs). However, the limited intrinsic absorptance of electrochromic materials impedes a satisfying solar-thermal conversion. Herein, bioinspired by the Paradisaeidae’s super black feathers, multiscale hierarchical structure is purposely made to compose of WO3-x nanowires (WNWs) and silver nanowires (AgNWs), where WNWs are grown on AgNWs in different orientations (denoted as WAg). Our ray tracing simulation reveals its underlying absorption mechanism, demonstrating both an increased optical path and a concentrated energy distribution. Comparably, the WAg-AED exhibits much enhanced absorption (87.0 vs. 68.5 % across the entire solar spectrum) and a broader surface temperature change (51.2 vs. 39.7 °C within 8 min) under 1 solar illumination. This leads to a rapid recovery of electrochromic/electrochemical performance even conducted at −20 °C. Notably, upon irradiation for 12 min, the areal capacities of WAg-AED at 0.5mA cm−2 increase by 3.8 and 1.7 times, when compared to the device operating at −20 °C and room temperature, respectively. The WAg-AED establishes a close connection between the photo-thermal conversion and electrochemistry, proving a new pathway in the development of sustainable electronics.

Recent progress of group III-V materials-based nanostructures for photodetection.

Due to the suitable bandgap structure, efficient conversion rates of photon to electron, adjustable optical bandgap, high electron mobility/aspect ratio, low defects, and outstanding optical and electrical properties for device design, III-V semiconductors have shown excellent properties for optoelectronic applications, including photodiodes, photodetectors, solar cells, photocatalysis, etc. In particular, III-V nanostructures have attracted considerable interest as a promising photodetector platform, where high-performance photodetectors can be achieved based on the geometry-related light absorption and carrier transport properties of III-V materials. However, the detection ranges from Ultraviolet to Terahertz including broadband photodetectors of III-V semiconductors still have not been more broadly development despite significant efforts to obtain the high performance of III-V semiconductors. Therefore, the recent development of III-V photodetectors in a broad detection range from Ultraviolet to Terahertz, and future requirements are highly desired. In this review, the recent development of photodetectors based on III-V semiconductor with different detection range is discussed. First, the bandgap of III-V materials and synthesis methods of III-V nanostructures are explored, subsequently, the detection mechanism and key figures-of-merit for the photodetectors are introduced, and then the device performance and emerging applications of photodetectors are provided. Lastly, the challenges and future research directions of III-V materials for photodetectors are presented.

Green-prepared high-performance electromagnetic wave absorption Ni6W6C/Co2O3@C composites and related broadband absorption device

In recent years, the synthesis of absorbing materials using green and environmentally friendly natural raw materials have become a research topic, but green and environmentally friendly materials with both high performance and simple synthesis steps still need to be developed. In this work, glucose and metal organic framework (MOF) were used to prepare composite materials with strong absorbing ability and low cost. We chose glucose, which is convenient to purchase on the market, as the raw material and constructed MOF derivatives with carbon shell skeleton nanostructures through a simple method of hydrothermal and annealing. Compared to the raw materials of traditional absorbing materials, glucose has environmentally friendly, low-cost and green characteristics. We characterized the microstructure and morphology of the material. In addition, we also analyzed the material composition and absorption mechanism of Ni6W6C/Co2O3@C. We have found from the theoretical analysis and simulation results of transmission lines that the minimum reflection loss (RLmin) value of Ni6W6C/Co2O3@C material at 5.43 GHz and 4.76 mm is −56.68 dB. And the effective absorption bandwidth (EAB) at 2.04 mm can reach 7.12 GHz. We load the best sample to the honeycomb structure, a broadband microwave absorber was designed for simulation. The results show that the broadband microwave absorber can achieve an average electromagnetic wave (EMW) loss of more than 99 % in the 0.3–16.04 GHz frequency band (RL value is less than −20 dB), and an average EMW loss of more than 90 % in the 16.04–18 GHz frequency band (RL value less than −10 dB). The composite structure of glucose and MOF derivatives enhances the dielectric loss of the material and enriches various EMW loss mechanisms. Finally, a green, environmental-friendly, high-performance absorbing material with a simple synthesis method is prepared. These results provide insights into the research on EMW absorption of composite materials and new methods for referring.

A DFT Study of Optoelectronic and Photo-catalytic Properties in 2D Copper and Silver Halides Through Strain Engineering

By using first principles calculations, the electronic, optical, photo-catalytic properties and the effect of in-plane bi-axial strain are investigated for Copper halides (CuCl, CuBr, and CuI) ML and silver halides (AgCl AgBr and AgI) ML. The results show that all the studied semiconductors have indirect bandgap while under the strain of (−8% to +8%), the bandgap has changed differently. Projected density of states revealed that CBM and VBM are mainly contributed by p-orbital and d-orbital of Cu-atom respectively in the case of all Copper halides (CuCl, CuBr, and CuI). Similarly, in the case of Silver halides (AgCl, AgBr, and AgI) CBM and VBM are mainly contributed by p-orbital and d-orbital of Ag-atom respectively. Phonon band structures of all unstrained monolayers are thermodynamically stable. The computed real part ε 1(ω) and the imaginary part ε 2(ω) of dielectric function revealed that CuCl and CuBr are suitable for the development of devices that may work in the infrared range while other materials such as CuI, AgCl, AgBr, and AgI are suitable for the development of devices that may work in the visible range. However, all the materials have a high absorption I(ω) of visible light as well. I(ω) under the strain of (−8% to +8%) is also computed, which shows that strain can effectively increase absorption of materials in the visible region. Both E VBM and E CBM in CuCl, CuBr, CuI, AgCl, and AgBr (ML) attain favorable positions that’s why these materials are appropriate for water splitting at pH = 0 while AgI (ML) is suitable for the reduction of water but not for oxidation.

Temperature dependence of THz generation efficiency, THz refractive index, and THz absorption in lithium-niobate around 275 GHz

In this study, we demonstrate the capabilities of the pulse train excitation approach in determining key material properties of nonlinear crystals, such as refractive index, thermo-optic coefficient, and absorption. The method provides reliable results even at relatively low THz frequencies, where other characterization methods, such as THz time-domain spectroscopy, have difficulties. To illustrate the capabilities of our approach, we used pulse trains with 800-fs long pulses and adjustable time delay to investigate the material properties of periodically poled lithium niobate (PPLN) crystal with a poling period of 400 µm. Via scanning the incident pulse-train frequency, we measured the frequency response of the crystal at different temperatures (78-350 K), which enabled us to determine the temperature dependence of the refractive index and thermo-optic coefficient of the PPLN crystal around 275 GHz with very high precision. We further studied the variation of THz generation efficiency with temperature in detail to understand the temperature dependence of THz absorption in PPLN material. The technique employed is quite general and could be applied to both other frequency ranges and nonlinear crystals.

Analyzing Formation and Absorption of Avascular Subretinal Hyperreflective Material in nAMD From OCTA-Based Insights

To investigate the formation and absorption of avascular subretinal hyperreflective material (avSHRM) in neovascular age-related macular degeneration (nAMD) based on optical coherence tomography angiography (OCTA) characteristics. Prospective cohort study. This study included patients with treatment-naive nAMD who were followed up for 3 months. Subjects were classified into an avSHRM group and a non-avSHRM group based on the presence of avSHRM at baseline. Quantitative OCTA characteristics including explant area, perimeter, vessel area, density, length, junctions, endpoints, lacunarity, maximum vessel caliber, vessel dispersion, and fractal dimension were assessed, and 3-dimensional volume and optical density ratio (ODR) of avSHRM were measured. Comparison analyses, correlation coefficients, and regression models were applied to explore factors associated with avSHRM formation and absorption. A total of 88 eyes from 88 patients (39 female) were enrolled. Compared to the non-avSHRM group, the avSHRM group exhibited a more intricate vasculature, characterized by higher values of macular neovascularization (MNV) perimeter, vessel area, total vessel length, total number of junctions, and total number of endpoints (all P < .05), as well as the maximum vessel caliber (P < .001). In the multivariate model, which was adjusted for age, sex, and types of medications, avSHRM absorption was correlated with baseline average vessel length, maximum vessel caliber, and avSHRM ODR (standardized β = 0.274, -0.367, and -0.334; P = .049, .010, and .018, respectively), with an adjusted R² of 0.453. Quantitative OCTA measurements can be used for assessing the dynamics of avSHRM in nAMD. Patients with more complex vasculature are at higher risk for avSHRM formation. Average vessel length, maximum vessel diameter, and avSHRM ODR play a role in its absorption.

Well-posedness of a bulk-surface convective Cahn–Hilliard system with dynamic boundary conditions

We consider a general class of bulk-surface convective Cahn–Hilliard systems with dynamic boundary conditions. In contrast to classical Neumann boundary conditions, the dynamic boundary conditions of Cahn–Hilliard type allow for dynamic changes of the contact angle between the diffuse interface and the boundary, a convection-induced motion of the contact line as well as absorption of material by the boundary. The coupling conditions for bulk and surface quantities involve parameters K,L∈[0,∞]\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$K,L\\in [0,\\infty ]$$\\end{document}, whose choice declares whether these conditions are of Dirichlet, Robin or Neumann type. We first prove the existence of a weak solution to our model in the case K,L∈(0,∞)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$K,L\\in (0,\\infty )$$\\end{document} by means of a Faedo–Galerkin approach. For all other cases, the existence of a weak solution is then shown by means of the asymptotic limits, where K and L are sent to zero or to infinity, respectively. Eventually, we establish higher regularity for the phase-fields, and we prove the uniqueness of weak solutions given that the mobility functions are constant.

Enhanced broadband sound absorption of multi-layer composite material based on three-dimensional warp-knitted spacer fabric

Compared with other sound-absorbing materials, spacer fabric with a “sandwich” structure has many advantages, such as light weight, an environmentally friendly production process, recyclability, versatility, low production cost and high efficiency, and strong designability of the organizational structure. However, as a porous sound-absorbing material, the effective sound-absorbing frequency band of the spacer fabric is concentrated at high frequencies, so the sound-absorbing performance needs to be improved. This paper establishes a Johnson–Champoux–Allard theoretical model by using a genetic algorithm to characterize the sound absorption performance of the three-dimensional (3D) warp-knitted spacer fabric. The theoretical model is validated through finite element analysis and experimental methods. Based on this model, two composite materials are designed to improve the sound absorption performance: (1) multi-layer spacer fabric composite material and (2) multi-layer spacer fabric-aluminum foil composite material. Numerical simulation and experimental results show that the sound absorption performance is significantly improved by widening the effective frequency band and increasing the sound absorption coefficient. The contribution of this paper is twofold. Firstly, the theoretical acoustic model of 3D warp-knitted spacer fabric is established. Secondly, the superior sound absorption performance is achieved by proposing multi-layer and multi-material composite material. The spacer fabric-based composite material has broad application prospects in the field of noise reduction and sound insulation. The paper provides a theoretical basis and more strategies for the acoustic and multifunctional design of spacer fabric in the future.

Empowerment and Provision of Early Health Education to Children in Orphanages

This Community Empowerment Program involves delivering education on handwashing techniques and raising awareness about the dangers of drugs to children living in the Ar-Ridho Orphanage. Consisting of three stages, namely planning, implementation, and evaluation, this service successfully generated enthusiasm among the participants during the delivery of the materials and handwashing practice sessions. Good information absorption occurred because the material was tailored to their age. Socialization about drugs was also conducted with the aim of providing understanding of their dangers and encouraging them to stay away from drugs from an early age. This activity combines delivering material about drugs with interactive games and quizzes, strengthening the children's understanding of the risks of drug abuse. The results are expected to enhance their understanding and foster a spirit to stay away from drug abuse. Throughout the socialization process, the participants showed enthusiasm both when listening to the material and when practicing proper handwashing. This is because of the use of strategies, methods, and media tailored to their age, allowing participants to understand the socialization material well during this service. Therefore, there is a need for ongoing supervision from the caretakers at the orphanage to ensure the absorption of the taught material.

Subpore-mediated tunable water absorption in nanoparticle-based materials

In the quest for advanced energy-efficient materials, a reversible adsorption process of water on nanoparticles presents a promising avenue for enhancing the thermal insulation and absorption capabilities of nanoparticle-based materials. Molecular dynamics simulation is carried out to elucidate the intricate water absorption dynamics at the nanoscale. Nanoparticles featuring subpore structures – rather than the conventional ideal spherical models – are utilized to investigate water absorption behavior. Our findings delineate absorption mechanisms – surface adsorption (Mg/M0 of 1.00 with specific area of 632.5 m2/g), transition (Mg/M0 of 0.75 with specific area of 897.0 m2/g), and penetration (Mg/M0 of 0.59 and 0.47, with specific area of 1003.0 and 1160.0 m2/g, respectively) – underscoring the critical role of subpore configurations in modulating these processes. Notably, an optimal nanoparticle structural parameter is identified, optimizing the balance between water adsorption capacity and thermal insulation properties. We unveil a novel mediating effect of subpores that significantly counters the formation of water bridges between nanoparticles – an inevitability in nanoporous materials – thus bolstering material stability and performance. The insights gained from this study shed light on the fundamental mechanisms governing water-nanoparticle interactions.

Anti-Resonant Hollow-Core Fibers with High Birefringence and Low Loss for Terahertz Propagation

A new type of anti-resonant hollow-core fiber for terahertz waveguides is proposed. By introducing central support pillars and an elliptical structure, the fiber achieves high birefringence while maintaining low confinement loss and low material absorption loss. The fiber structure is optimized through simulation using the finite element method. The optimized fiber exhibits a birefringence of up to 1.22 × 10−2 at a frequency of 1 THz, with a confinement loss of 8.34 × 10−6 dB/cm and a material absorption loss of 7.17 × 10−3 dB/cm. Furthermore, when the bending radius of the fiber is greater than 12 cm, the bending loss of the anti-resonant optical fiber at 1 THz is less than 1.36 × 10−4 dB/cm, demonstrating good bending resistance and high practical value. It is expected to play a significant role in optical communication systems.

Experimental Investigation into the Failure Mechanisms of Fabric Membrane Materials with Defective Flat Round Cracks

The emphasis of this study is placed on the investigation into the failure mechanisms of the fabric membranes when exposed to such defective cracks. This experimental study investigates the initial crack of a flat circle and conducts a uniaxial shear test on the membrane materials. The deformation of the membrane materials is obtained through an optical non-contact scanner. Our study has been conducted to assess the crack propagation of fabric membrane materials at different angles. The relationships between crack width and stress together with stress and strain are also obtained. Based on the results, a mechanic of failure on the membrane was proposed. Moreover, new findings into the ductility and energy absorption of the fabric membrane materials have been established to inform the failure mechanisms.

Stepwise Charge/Energy Transfer in MR-TADF Molecule-Doped Exciplex for Ultralong Persistent Luminescence Activated with Visible Light.

Organic long-persistent luminescence (OLPL), which relies on energy storage for delayed light emission by the charge separation state, has attracted intense attention in various optical applications. However, charge separation (CS) is efficient only under ultraviolet excitation in most OLPL systems because it requires a driving force from the large energy difference between the local excited (LE) and charge transfer (CT) states. In this study, a multiresonance thermally activated delayed fluorescence (MR-TADF) molecule is incorporated into an exciplex system to achieve efficient OLPL in a composite material activated by visible light via a stepwise charge/energy transfer process. The enhanced absorption of the composite material facilitated a tenfold increase in the duration of the OLPL, which can last for several hours under visible light excitation. The excited state of the MR-TADF molecule tends to charge transfer to the acceptor, followed by energy transfer to the exciplex, which benefits from the small difference between the LE and CT states owing to the inherent CS characteristics of the opposing resonance effect. Afterglow displays of these composite materials are fabricated to demonstrate their considerable potential in encryption patterns and emergency lights, which take advantage of their excellent processability, visible light activation, and tunable luminescence properties.

Exploring Age Differences in Absorption and Enjoyment during Story Listening

Using naturalistic spoken narratives to investigate speech processes and comprehension is becoming increasingly popular in experimental hearing research. Yet, little is known about how individuals engage with spoken story materials and how listening experiences change with age. We investigated absorption in the context of listening to spoken stories, explored predictive factors for engagement, and examined the utility of a scale developed for written narratives to assess absorption for auditory materials. Adults aged 20–78 years (N = 216) participated in an online experimental study. Participants listened to one of ten stories intended to be engaging to different degrees and rated the story in terms of absorption and enjoyment. Participants of different ages rated the stories similarly absorbing and enjoyable. Further, higher mood scores predicted higher absorption and enjoyment ratings. Factor analysis showed scale items approximately grouped according to the original scale dimensions, suggesting that absorption and enjoyment experiences may be similar for written and spoken stories, although certain items discriminated less effectively between stories intended to be more or less engaging. The present study provides novel insights into how adults of different ages engage in listening and supports using naturalistic speech stimuli in hearing research.

Rapidly damping hydrogels engineered through molecular friction

Hydrogels capable of swift mechanical energy dissipation hold promise for a range of applications including impact protection, shock absorption, and enhanced damage resistance. Traditional energy absorption in such materials typically relies on viscoelastic mechanisms, involving sacrificial bond breakage, yet often suffers from prolonged recovery times. Here, we introduce a hydrogel designed for friction-based damping. This hydrogel features an internal structure that facilitates the motion of a chain walker within its network, effectively dissipating mechanical stress. The hydrogel network architecture allows for rapid restoration of its damping capacity, often within seconds, ensuring swift material recovery post-deformation. We further demonstrate that this hydrogel can significantly shield encapsulated cells from mechanical trauma under repetitive compression, owing to its proficient energy damping and rapid rebound characteristics. Therefore, this hydrogel has potential for dynamic load applications like artificial muscles and synthetic cartilage, expanding the use of hydrogel dampers in biomechanics and related areas.

Inverse design for laser-compatible infrared camouflage metasurface enabled by physics-driven neural network and genetic algorithm

Metasurface-based multi-band camouflage holds significant value in both military and civilian applications due to its superior performance and structural simplicity. Combining a physics-driven neural network (PNN) and genetic algorithm (GA), we designed the AZO-Ge disk metasurface capable of achieving 1.06 μm laser stealth, mid-infrared thermal camouflage and efficient thermal management. In contrast to conventional spectra prediction neural networks, the PNN adopts a data dimensionality reduction prediction paradigm, resulting in enhanced accuracy and accelerated convergence. The combination of PNN and GA in the inverse design effectively addresses the prevalent “one-to-many" and single-solution challenges encountered in tandem neural networks. Such data-driven approach makes metasurface design faster and more efficient. Finally, four groups of metasurface geometric parameters were designed by the PNN-GA framework. The designed metasurfaces exhibit low average emissivities (<0.3 and < 0.2, respectively) in the two atmospheric windows (3∼5 μm and 8∼14 μm), high average emissivity (>0.75) in the non-atmospheric window (5∼8 μm) and high absorptivity (>0.8) at 1.06 μm. We also demonstrate that these spectral properties are insensitive to the incident angles and polarizations. In addition, the electric field intensity distribution plots of the cross sections reveal that surface plasmon polariton (SPP) predominantly contributes to the high emission in the non-atmospheric window band, while the high absorptivity at 1.06 μm is attributed to the resonance and the intrinsic absorption of the Ge material. The designed metasurface with its simple structure suggests the potential for low-cost and large-scale fabrication in the future. Meanwhile, the combination of machine learning and evolutionary algorithms is a pioneering work in metasurface design and we believe our work will provide guidelines for the multi-solution design of complex metasurfaces.