The latent heat thermal energy storage system with solid-liquid phase-change material(SLPCM-LHTES)as energy storage medium provides outstanding advantages such as system simplicity,stable temperature control,and high ...The latent heat thermal energy storage system with solid-liquid phase-change material(SLPCM-LHTES)as energy storage medium provides outstanding advantages such as system simplicity,stable temperature control,and high energy storage density,showing great potential toward addressing the energy storage problems associated with decentralized,intermittent,and unstable renewable energy sources.Notably,effective heat transfer within the SLPCM-LHTES is crucial for extending its application potential.Therefore,a comprehensive understanding of the heat transfer processes in SLPCM-LHTES from a theoretical perspective is necessary.In this review,we propose a three-stage heat transfer pathway in SLPCM-LHTES,including external heating,interfacial heat transfer,and intrinsic phase transition processes.From the perspective of this three-stage pathway,the theoretical basis of heat transfer processes and typical efficiency enhancement strategies in SLPCM-LHTES are summarized.Moreover,an overview of the typical applications of SLPCM-LHTES in various fields,such as building energy efficiency,textiles and garments,and battery thermal management,is presented.Finally,the remaining challenges and possible avenues of research in this burgeoning field will also be discussed.展开更多
Oriented graphene aerogels have limited applica-tions because the flexibility of their graphene sheets and mi-crostructure give them a low skeleton strength,insufficient compression resilience,and poor flexibility.We ...Oriented graphene aerogels have limited applica-tions because the flexibility of their graphene sheets and mi-crostructure give them a low skeleton strength,insufficient compression resilience,and poor flexibility.We report the preparation of novel aerogel materials with a much better per-formance.Using the driving force of graphene oxide(GO)self-assembly andπ-πinteractions,carbon nanotubes(CNTs)were attached to the GO sheets,and an oriented composite carbon skeleton was constructed using“hydro-plastic foam-ing”.The introduction of CNTs significantly increased the strength of the skeleton and gave the aerogel an excellent re-versible compressibility.The innovative use of cold pressing greatly improved the thermal conductivity and flexibility of the aerogel,providing new ideas for the development of high-performance aerogels.Tests show that the obtained graphene composite aerogel has a reversible compressive strain of over 90%and can withstand 500 compression cycles along the direc-tion of pore accumulation.It can endure more than 10000 bending cycles perpendicular to the direction of composite carbon layer stacking,and its in-plane thermal conductivity reaches 64.5 W·m^(-1)·K^(-1).When filled with phase change materials,the high porosity of the carbon skeleton enables the material to have a high phase change filling rate,and its phase change enthalpy is greater than 150 J/g.Thanks to the exceptional flexibility of the carbon skeleton,the macrostructure of phase change materials can be bent as needed to adapt to thermal management scenarios and conform to device shapes.This significantly enhances practical application compatibility,providing flexible support for temperature control and thermal management across diverse device forms.展开更多
To address the limitations of conventional energy systems and optimize the energy conversion pathways and efficiency,a type of“five-in-one”multifunctional phase-change composite with magnetothermal,electrothermal,so...To address the limitations of conventional energy systems and optimize the energy conversion pathways and efficiency,a type of“five-in-one”multifunctional phase-change composite with magnetothermal,electrothermal,solar-thermal,and thermoelectric energy conversion and electromagnetic shielding functions is developed for multipurpose applications.Such a novel phase-change composite is fabricated by an innovative combination of paraffin wax(PW)as a phase-change material and a carbonized polyimide/Kevlar/graphene oxide@ZIF-67 complex aerogel as a supporting material.The carbonized complex aerogel exhibits a unique bidirectional porous structure with high porosity and robust skeleton to support the loading of PW.The reduced graphene oxide and Co NC resulting from high-temperature carbonization are anchored on the aerogel skeleton to generate high thermal conduction and magnetic effect,enhancing the phonon and electron transfer of the aerogel and improving its energy conversion efficiency.The phase-change composite not only exhibits excellent solar-thermal,thermoelectric,electrothermal,and magnetothermal energy conversion performance,but also achieves high electromagnetic interference shielding effectiveness of 66.2 d B in the X-band.The introduction of PW significantly improves the thermal energy-storage capacity during multi-energy conversion.The developed composite exhibits great application potential for efficient solar energy utilization,sustainable power generation,outdoor deicing,human thermal therapy,and electronic device protection.展开更多
To investigate thermal protection effects of heat sinking vest with phase-change material （PCM）, human thermoregulation model is introduced, and a thermal mathematical model of heat transfer with phase change has be...To investigate thermal protection effects of heat sinking vest with phase-change material （PCM）, human thermoregulation model is introduced, and a thermal mathematical model of heat transfer with phase change has been developed with the enthalpy method. The uniform energy equation is constructed for the whole domain, and the equation is implicitly discreted by control volume and finite difference method. Then the enthalpy in each node is solved by using chasing method to calculate the tridiagonal equations, and the inner surface temperature of PCM could be obtained. According to the human thermoregulation model of heat sinking vest, the dynamic temperature distribution and sweat of the body are solved. Calculation results indicate that the change of core temperature matches the experimental result, and the sweat difference is small. This thermal mathematical model of heat transfer with phase change is credible and appropriate. Through comparing the dynamic temperature distribution and sweat of the body wearing heat sinking vest to results of the body not wearing this clothing, it is evident that wearing heat sinking vest can reduce the body heat load significantly.展开更多
The era of information explosion is coming and information need to be continuously stored and randomly accessed over long-term periods,which constitute an insurmountable challenge for existing data centers.At present,...The era of information explosion is coming and information need to be continuously stored and randomly accessed over long-term periods,which constitute an insurmountable challenge for existing data centers.At present,computing devices use the von Neumann architecture with separate computing and memory units,which exposes the shortcomings of“memory bottleneck”.Nonvolatile memristor can realize data storage and in-memory computing at the same time and promises to overcome this bottleneck.Phase-change random access memory(PCRAM)is called one of the best solutions for next generation non-volatile memory.Due to its high speed,good data retention,high density,low power consumption,PCRAM has the broad commercial prospects in the in-memory computing application.In this review,the research progress of phase-change materials and device structures for PCRAM,as well as the most critical performances for a universal memory,such as speed,capacity,and power consumption,are reviewed.By comparing the advantages and disadvantages of phase-change optical disk and PCRAM,a new concept of optoelectronic hybrid storage based on phase-change material is proposed.Furthermore,its feasibility to replace existing memory technologies as a universal memory is also discussed as well.展开更多
A lithium-ion battery thermal management system has always been a hot spot in the battery industry. In this study, a novel high-thermal-conductivity composite phase-change material(CPCM) made by paraffin wax and silic...A lithium-ion battery thermal management system has always been a hot spot in the battery industry. In this study, a novel high-thermal-conductivity composite phase-change material(CPCM) made by paraffin wax and silicon was adopted to facilitate heat transfer. Moreover, high resistance or even insulation of CPCM is capable of preventing short circuits between the cells. The heat transfer mechanism of CPCMs was determined under a scanning electron microscope. A thermogravimetric analyzer was employed to determine the thermal stability. A diff erential scanning calorimeter was used to explore the thermophysical properties of the composite samples. By comparing the results of the experiment, it was reported that under the silicon carbide content of 5%, the parameters were better than others. The phase-change enthalpy of CPCM was 199.4 J/g, the leakage rate of liquid was 4.6%, and the melting point was 53.6℃. To verify the practicality of CPCM, a three-dimensional layered battery pack model was built in the COMSOL Multiphysics software. By simulating the thermal runaway inside the battery packs of various materials, it was reported that the addition of CPCM significantly narrowed the temperature range of the battery pack from 300–370 to 303–304 K. Therefore, CPCM can eff ectively increase the rate of heat transfer to prevent the chain of thermal runaway reactions. It also enables the battery pack to run at a stable temperature.展开更多
Based on the phase-change material Ge_(2)Sb_(2)Te_(5)(GST),achromatic metasurface optical device in the longer-infrared wavelength is designed.With the combination of the linear phase gradient GST nanopillar and the a...Based on the phase-change material Ge_(2)Sb_(2)Te_(5)(GST),achromatic metasurface optical device in the longer-infrared wavelength is designed.With the combination of the linear phase gradient GST nanopillar and the adjustment of the crystalline fraction m value of GST,the polarization insensitive achromic metalenses and beam deflector metasurface within the longer-infrared wavelength 9.5μm to 13μm are realized.The design results show that the achromatic metalenses can be focused on the same focal plane within the working waveband.The simulation calculation results show that the fullwidth at half-maximum(FWHM)of the focusing spot reaches the diffraction limit at each wavelength.In addition,the same method is also used to design a broadband achromatic beam deflector metasurface with the same deflection angle of 19°.The method proposed in this article not only provides new ideas for the design of achromatic metasurfaces,but also provides new possibilities for the integration of optical imaging,optical coding and other related optical systems.展开更多
Phase-change material(PCM)is generating widespread interest as a new candidate for artificial synapses in bioinspired computer systems.However,the amorphization process of PCM devices tends to be abrupt,unlike continu...Phase-change material(PCM)is generating widespread interest as a new candidate for artificial synapses in bioinspired computer systems.However,the amorphization process of PCM devices tends to be abrupt,unlike continuous synaptic depression.The relatively large power consumption and poor analog behavior of PCM devices greatly limit their applications.Here,we fabricate a GeTe/Sb2Te3 superlattice-like PCM device which allows a progressive RESET process.Our devices feature low-power consumption operation and potential high-density integration,which can effectively simulate biological synaptic characteristics.The programming energy can be further reduced by properly selecting the resistance range and operating method.The fabricated devices are implemented in both artificial neural networks(ANN)and convolutional neural network(CNN)simulations,demonstrating high accuracy in brain-like pattern recognition.展开更多
Faced with the world’s environmental and energy-related challenges,researchers are turning to innovative,sustainable and intelligent solutions to produce,store,and distribute energy.This work explores the trend of us...Faced with the world’s environmental and energy-related challenges,researchers are turning to innovative,sustainable and intelligent solutions to produce,store,and distribute energy.This work explores the trend of using a smart sensor to monitor the stability and efficiency of a salt-gradient solar pond.Several studies have been conducted to improve the thermal efficiency of salt-gradient solar ponds by introducing other materials.This study investigates the thermal and salinity behaviors of a pilot of smart salt-gradient solar ponds with(SGSP)and without(SGSPP)paraffin wax(PW)as a phase-change material(PCM).Temperature and salinity were measured experimentally using a smart sensor,with the measurements being used to investigate the stabilizing effects of placing the PCM in the solar pond’s lower convective zone.The experimental results show that the pond with the PCM(SGSPP)achieved greater thermal and salinity stability,with there being a lesser temperature and salinity gradient between the different layers when compared to a solar pond without thePCM(SGSP).The use of the PCM,therefore,helped control the maximum and minimum temperature of the pond’s storage zone.The UCZ has been found to operate approximately 4 degrees above the average ambient temperature of the day in the SGSPP and 7 degrees in SGSP.Moreover,an unstable situation is generated after 5 days from starting the operation and at 1.9 m from the bottom,and certain points have the tendency to be neutral from the upper depths in 1,3 m of the bottom.展开更多
Ge2 Sb2 Te5 is the most widely utilized chalcogenide phase-change material for non-volatile photonic applications,which undergoes amorphous-cubic and cubic-hexagonal phase transition under external excitations.However...Ge2 Sb2 Te5 is the most widely utilized chalcogenide phase-change material for non-volatile photonic applications,which undergoes amorphous-cubic and cubic-hexagonal phase transition under external excitations.However,the cubic-hexagonal optical contrast is negligible,only the amorphous-cubic phase transition of Ge_(2)Sb_(2)Te_(5) is available.This limits the optical switching states of traditional active displays and absorbers to two.We find that increasing structural disorder difference of cubic-hexagonal can increase optical contrast close to the level of amorphous-cubic.Therefore,an amorphous-cubichexagonal phase transition with high optical contrast is realized.Using this phase transition,we have developed display and absorber with three distinct switching states,improving the switching performance by 50%.Through the combination of first-principle calculations and experiments,we reveal that the key to increasing structural disorder difference of amorphous,cubic and hexagonal phases is to introduce small interstitial impurities(like N)in Ge2 Sb2 Te5,rather than large substitutional impurities(like Ag)previously thought.This is explained by the formation energy and lattice distortion.Based on the impurity atomic radius,interstitial site radius and formation energy,C and B are also potential suitable impurities.In addition,introducing interstitial impurities into phase-change materials with van der Waals gaps in stable phase such as GeSb_(4) Te_(7),GeSb_(2) Te_(4),Ge_(3)Sb_(2) Te_(6),Sb_(2)Te_(3) will produce high optical contrast amorphous-metastable-stable phase transition.This research not only reveals the important role of interstitial impurities in increasing the optical contrast between metastable-stable phases,but also proposes varieties of candidate matrices and impurities.This provides new phase-change materials and design methods for non-volatile optical devices with multi-switching states.展开更多
All-dielectric metasurface, which features low optical absorptance and high resolution, is becoming a promising candidate for full-color generation. However, the optical response of current metamaterials is fixed and ...All-dielectric metasurface, which features low optical absorptance and high resolution, is becoming a promising candidate for full-color generation. However, the optical response of current metamaterials is fixed and lacks active tuning. In this work, we demonstrate a reconfigurable and polarization-dependent active color generation technique by incorporating low-loss phase change materials(PCMs) and CaF_2 all-dielectric substrate. Based on the strong Mie resonance effect and low optical absorption structure, a transflective, full-color with high color purity and gamut value is achieved. The spectrum can be dynamically manipulated by changing either the polarization of incident light or the PCM state. High transmittance and reflectance can be simultaneously achieved by using low-loss PCMs and substrate. The novel active metasurfaces can bring new inspiration in the areas of optical encryption, anti-counterfeiting, and display technologies.展开更多
Today, latent heat storage technology has advanced to allow reuse of waste heat in the middle-temperature range. This paper describes an approach to develop a latent heat storage system using middle-temperature waste ...Today, latent heat storage technology has advanced to allow reuse of waste heat in the middle-temperature range. This paper describes an approach to develop a latent heat storage system using middle-temperature waste heat (~100oC - 200oC) from factories. Direct contact melting and solidification behavior between a heat-transfer fluid (oil) and a latent heat storage material mixture were observed. The mixture consisted of mannitol and erythritol (Cm = 70 mass %, Ce = 30 mass %) as a phase-change material (PCM). The weight of the PCM was 3.0 kg and the flow rate of the oil, foil, was 1.0, 1.5, or 2.0 kg/min. To decrease the solidified height of the PCM mixture during the solidification process, a perforated partition plate was installed in the PCM region in the heat storage vessel. PCM coated oil droplets were broken by the perforated partition plate, preventing the solidified height of the PCM from increasing. The solidification and melting processes were repeated using metal fiber. It was found that installing the metal fiber was more effective than installing the perforated partition plate to prevent the flow out problem of the PCM.展开更多
Metasurfaces provide a potent platform for the dynamic manipulation of electromagnetic waves.Coupled with phase-change materials,they facilitate the creation of versatile metadevices,showcasing various tunable functio...Metasurfaces provide a potent platform for the dynamic manipulation of electromagnetic waves.Coupled with phase-change materials,they facilitate the creation of versatile metadevices,showcasing various tunable functions based on the transition between amorphous and crystalline states.However,the inherent limitation in tunable states imposes constraints on the multiplexing channels of metadevices.Here,this paper introduces a novel approach-a multi-functional metadevice achieved through the two-level control of the encoding phasechange metaatoms.Utilizing the phase-change material Ge_(2)Sb_(2)Se_(4)Te1(GSST)and high refractive-index liquid diiodomethane(CH_(2)I_(2)),this paper showcases precise control over electromagnetic wave manipulation.The GSST state governs the tunable function,switching it ON and OFF,while the presence of liquid in the hole dictates the deflection angle when the tunable function is active.Importantly,our tunable coding metasurface exhibits robust performance across a broad wavelength spectrum.The incorporation of high refractive-index liquid extends the regulatory dimension of the metadevice,enabling dynamic switching of encoding bit levels.This two-level tunable metadevice,rooted in phase-change materials,presents a promising avenue for the dynamic control of functions.展开更多
Integration of phase-change materials(PCMs)created a unique opportunity to implement reconfigurable photonics devices that their performance can be tuned depending on the target application.Conventional PCMs such as G...Integration of phase-change materials(PCMs)created a unique opportunity to implement reconfigurable photonics devices that their performance can be tuned depending on the target application.Conventional PCMs such as Ge-Sb-Te(GST)and Ge-Sb-Se-Te(GSST)rely on melt-quench and high temperature annealing processes to change the organization of the molecules in the materials’crystal.Such a reorganization leads to different optical,electrical,and thermal properties which can be exploited to implement photonic memory cells that are able to store the data at different resistance or optical transmission levels.Despite the great promise of conventional PCMs for realizing reconfigurable photonic memories,their slow and extremely power-hungry thermal mechanisms make scaling the systems based on such devices challenging.In addition,such materials do not offer a stable multi-level response over a long period of time.To address these shortcomings,the research carried out in this study shows the proof of concept to implement next-generation photonic memory cells based on two-dimensional(2D)birefringence PCMs such as SnSe,which offer anisotropic optical properties that can be switched ferroelectrically.We demonstrate that by leveraging the ultrafast and low-power crystallographic direction change of the material,the optical polarization state of the input optical signal can be changed.This enables the implementation of next-generation high-speed polarization-encodable photonic memory cells for future photonic computing systems.Compared to the conventional PCMs,the proposed SnSe-based photonic memory cells offer an ultrafast switching and low-loss optical response relying on ferroelectric property of SnSe to encode the data on the polarization state of the input optical signal.Such a polarization encoding scheme also reduces memory read-out errors and alleviates the scalability limitations due to the optical insertion loss often seen in optical transmission encoding.展开更多
To address the intermittent challenges of new energy and waste heat recovery as well as counteract the issues of corrosion and overcooling in phase-change materials,this study develops and investigates a medium-temper...To address the intermittent challenges of new energy and waste heat recovery as well as counteract the issues of corrosion and overcooling in phase-change materials,this study develops and investigates a medium-temperature phase-change capsule(PCC)through experiments and numerical simulations.The thermal cycle stability testing of the developed PCC,subjected to 150 cycles to evaluate its performance,demonstrated that the capsule's surface remained intact with no signs of leakage.The enthalpy-porosity method combined with the volume-of-fluid method was used to establish a numerical model to simulate the phase-change process in capsules with two structures:one with a central cavity and the other with a top cavity.Results indicated that when using 304 stainless steel as the wall material for both structures,the PCC with the centrally located cavity melted28.3%faster than that with the cavity at the top.When using different materials as wall coverings,the melting rate of the PCC made of polytetrafluoroethylene(PTFE)was 22.1%slower than that of the capsule made of 304stainless steel.Conversely,the modified PTFE PCC melted 15.2%faster than the stainless steel-based PCC.Furthermore,when using PCCs having different diameters,the time differences for complete melting between the PTFE and stainless steel-based PCCs were 118 s and 66 s for the capsules having diameters of 24 mm and 16 mm,respectively,indicating that the time difference decreased with decreasing capsule diameter.展开更多
Theoretical simulation of phase change materials such as Ge-Sb-Te has suffered from two methodological issues.On the one hand,there is a lack of efficient band gap correction method for density functional theory that ...Theoretical simulation of phase change materials such as Ge-Sb-Te has suffered from two methodological issues.On the one hand,there is a lack of efficient band gap correction method for density functional theory that is suitable for these materials in both crystalline and amorphous phases,while maintaining the computational complexity comparable to local density approximation.On the other hand,analysis of the coordination number in amorphous phases relies on an integration involving the radial distribution function,which adds to the complexity.In this work,we find that the shell DFT-1/2 method offers overall band gap accuracy for phase-change materials comparable to that of the HSE06 hybrid functional,while its computational cost is orders of magnitude lower.Moreover,the mixed length-angle coordination number theory enables calculating the coordination numbers in the amorphous phase directly from the structure,with definite outcomes.The two methodologies could be helpful for high-throughput simulations of phase change materials.展开更多
In complex environments,infrared camouflage within the long-wave infrared range is essential for modern defense and surveillance applications,requiring precise control over both radiative and scattering properties of ...In complex environments,infrared camouflage within the long-wave infrared range is essential for modern defense and surveillance applications,requiring precise control over both radiative and scattering properties of military targets.For practical implementation,developing surfaces that integrate dynamic emissivity control,low specular reflectance,and scalable fabrication processes remains a significant challenge.Here,a novel infrared camouflage device is proposed to simultaneously achieve low specular reflectance(<0.1)and dynamic infrared camouflage.The device seamlessly blends into backgrounds with temperatures ranging from 35°C to 45°C by tuning the emissivity of the device,which is attained by controlling the Ge2Sb2Te5 phase change.In addition,it reflects almost no surrounding thermal signals compared with the conventional low-emissivity smooth surface.The thermal camouflage remains effective and stable across observation angles ranging from 20°to 60°.This work proposes a novel approach to simultaneously reducing specular reflection and dynamic emissivity control,potentially inspiring future research and applications in multispectral camouflage and stealth technology.展开更多
Solar anti-icing/de-icing is an environmentally friendly way to convert light energy into heat with the purpose of melting/removing ice. However, the inherent intermittency of solar irradiation limits the application ...Solar anti-icing/de-icing is an environmentally friendly way to convert light energy into heat with the purpose of melting/removing ice. However, the inherent intermittency of solar irradiation limits the application of solar-thermal energy-conversion technologies, when continuous de-icing is required. Herein, we investigate a solar phase-change material(SPCM) that consists of expanded graphite(EG)/paraffin/polydimethylsiloxane(PDMS), which can not only perform the solar-thermal conversion but also release/store thermal energy. Under sunlight, the SPCM effectively collects and converts the light energy into thermal energy for later antiicing/de-icing. To prepare for a no-light period, e.g., in the evening, the converted thermal energy can be stored in the SPCM using a phase transition. In this way, the energy can be released when needed to keep the temperature of a surface from freezing. The SPCM surface shows excellent anti-icing/de-icing properties such as a long droplet freeze-delay time(td> 2 h), even at an ultra-low temperature(-40℃), using only the light of one sun. This freeze-delay time is much longer than that for a surface without PCM. The tested SPCM surfaces show a high de-icing rate(2.21 kg m^(-2)h^(-1)) under real-life conditions. In addition, the SPCM shows a high de-icing rate and excellent durability. This study provides a promising route for the utilization of solar energy in anti-icing/de-icing applications.展开更多
We numerically demonstrate a novel ultra-broadband polarization-independent metamaterial perfect absorber in the visible and near-infrared region involving the phase-change material Ge_2Sb_2Te_5(GST).The novel perfect...We numerically demonstrate a novel ultra-broadband polarization-independent metamaterial perfect absorber in the visible and near-infrared region involving the phase-change material Ge_2Sb_2Te_5(GST).The novel perfect absorber scheme consists of an array of high-index strong-absorbance GST square resonators separated from a continuous Au substrate by a low-index lossless dielectric layer(silica)and a high-index GST planar cavity.Three absorption peaks with the maximal absorbance up to 99.94% are achieved,owing to the excitation of plasmon-like dipolar or quadrupole resonances from the high-index GST resonators and cavity resonances generated by the GST planar cavity.The intensities and positions of the absorption peaks show strong dependence on structural parameters.A heat transfer model is used to investigate the temporal variation of temperature within the GST region.The results show that the temperature of amorphous GST can reach up to 433 K of the phase transition temperature from room temperature in just 0.37 ns with a relatively low incident light intensity of 1.11×10~8W∕m^2,due to the enhanced ultra-broadband light absorbance through strong plasmon resonances and cavity resonance in the absorber.The study suggests a feasible means to lower the power requirements for photonic devices based on a thermal phase change via engineering ultra-broadband light absorbers.展开更多
A tunable plasmonic perfect absorber with a tuning range of 650 nm is realized by introducing a 20 nm thick phase-change material Ge2Sb2Te5 layer into the metal–dielectric–metal configuration.The absorption at the p...A tunable plasmonic perfect absorber with a tuning range of 650 nm is realized by introducing a 20 nm thick phase-change material Ge2Sb2Te5 layer into the metal–dielectric–metal configuration.The absorption at the plasmonic resonance is kept above 0.96 across the whole tuning range.In this work we study this extraordinary optical response numerically and reveal the geometric conditions which support this phenomenon.This work shows a promising route to achieve tunable plasmonic devices for multi-band optical modulation,communication,and thermal imaging.展开更多
基金financial support was provided by the National Natural Science Foundation of China(Nos.52476146,52006008,and 52471219)the Guangdong Basic and Applied Basic Research Foundation(2023A1515140059 and 2025A1515011255)+2 种基金the Peking University Third Hospital Haidian transformation project(HDCXZHKC2023210)the National Foreign Expert Individual Human Project(Category H,No.H20240116)the State Key Laboratory of New Ceramic Materials Tsinghua University(No.KFZD202402).
文摘The latent heat thermal energy storage system with solid-liquid phase-change material(SLPCM-LHTES)as energy storage medium provides outstanding advantages such as system simplicity,stable temperature control,and high energy storage density,showing great potential toward addressing the energy storage problems associated with decentralized,intermittent,and unstable renewable energy sources.Notably,effective heat transfer within the SLPCM-LHTES is crucial for extending its application potential.Therefore,a comprehensive understanding of the heat transfer processes in SLPCM-LHTES from a theoretical perspective is necessary.In this review,we propose a three-stage heat transfer pathway in SLPCM-LHTES,including external heating,interfacial heat transfer,and intrinsic phase transition processes.From the perspective of this three-stage pathway,the theoretical basis of heat transfer processes and typical efficiency enhancement strategies in SLPCM-LHTES are summarized.Moreover,an overview of the typical applications of SLPCM-LHTES in various fields,such as building energy efficiency,textiles and garments,and battery thermal management,is presented.Finally,the remaining challenges and possible avenues of research in this burgeoning field will also be discussed.
文摘Oriented graphene aerogels have limited applica-tions because the flexibility of their graphene sheets and mi-crostructure give them a low skeleton strength,insufficient compression resilience,and poor flexibility.We report the preparation of novel aerogel materials with a much better per-formance.Using the driving force of graphene oxide(GO)self-assembly andπ-πinteractions,carbon nanotubes(CNTs)were attached to the GO sheets,and an oriented composite carbon skeleton was constructed using“hydro-plastic foam-ing”.The introduction of CNTs significantly increased the strength of the skeleton and gave the aerogel an excellent re-versible compressibility.The innovative use of cold pressing greatly improved the thermal conductivity and flexibility of the aerogel,providing new ideas for the development of high-performance aerogels.Tests show that the obtained graphene composite aerogel has a reversible compressive strain of over 90%and can withstand 500 compression cycles along the direc-tion of pore accumulation.It can endure more than 10000 bending cycles perpendicular to the direction of composite carbon layer stacking,and its in-plane thermal conductivity reaches 64.5 W·m^(-1)·K^(-1).When filled with phase change materials,the high porosity of the carbon skeleton enables the material to have a high phase change filling rate,and its phase change enthalpy is greater than 150 J/g.Thanks to the exceptional flexibility of the carbon skeleton,the macrostructure of phase change materials can be bent as needed to adapt to thermal management scenarios and conform to device shapes.This significantly enhances practical application compatibility,providing flexible support for temperature control and thermal management across diverse device forms.
基金supported by the Beijing Natural Science Foundation(Grant No.:2242049)。
文摘To address the limitations of conventional energy systems and optimize the energy conversion pathways and efficiency,a type of“five-in-one”multifunctional phase-change composite with magnetothermal,electrothermal,solar-thermal,and thermoelectric energy conversion and electromagnetic shielding functions is developed for multipurpose applications.Such a novel phase-change composite is fabricated by an innovative combination of paraffin wax(PW)as a phase-change material and a carbonized polyimide/Kevlar/graphene oxide@ZIF-67 complex aerogel as a supporting material.The carbonized complex aerogel exhibits a unique bidirectional porous structure with high porosity and robust skeleton to support the loading of PW.The reduced graphene oxide and Co NC resulting from high-temperature carbonization are anchored on the aerogel skeleton to generate high thermal conduction and magnetic effect,enhancing the phonon and electron transfer of the aerogel and improving its energy conversion efficiency.The phase-change composite not only exhibits excellent solar-thermal,thermoelectric,electrothermal,and magnetothermal energy conversion performance,but also achieves high electromagnetic interference shielding effectiveness of 66.2 d B in the X-band.The introduction of PW significantly improves the thermal energy-storage capacity during multi-energy conversion.The developed composite exhibits great application potential for efficient solar energy utilization,sustainable power generation,outdoor deicing,human thermal therapy,and electronic device protection.
文摘To investigate thermal protection effects of heat sinking vest with phase-change material （PCM）, human thermoregulation model is introduced, and a thermal mathematical model of heat transfer with phase change has been developed with the enthalpy method. The uniform energy equation is constructed for the whole domain, and the equation is implicitly discreted by control volume and finite difference method. Then the enthalpy in each node is solved by using chasing method to calculate the tridiagonal equations, and the inner surface temperature of PCM could be obtained. According to the human thermoregulation model of heat sinking vest, the dynamic temperature distribution and sweat of the body are solved. Calculation results indicate that the change of core temperature matches the experimental result, and the sweat difference is small. This thermal mathematical model of heat transfer with phase change is credible and appropriate. Through comparing the dynamic temperature distribution and sweat of the body wearing heat sinking vest to results of the body not wearing this clothing, it is evident that wearing heat sinking vest can reduce the body heat load significantly.
基金the National Natural Science Foundation of China(Grant Nos.21773291,61904118,and 22002102)the Natural Science Foundation of Jiangsu Province,China(Grant Nos.BK20190935 and BK20190947)+3 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(Grant Nos.19KJA210005,19KJB510012,19KJB120005,and 19KJB430034)the Fund from the Suzhou Key Laboratory for Nanophotonic and Nanoelectronic Materials and Its Devices(Grant No.SZS201812)the Science Fund from the Jiangsu Key Laboratory for Environment Functional Materialsthe State Key Laboratory of Transducer Technology,Shanghai Institute of Microsystem and Information Technology,Chinese Academy of Sciences.
文摘The era of information explosion is coming and information need to be continuously stored and randomly accessed over long-term periods,which constitute an insurmountable challenge for existing data centers.At present,computing devices use the von Neumann architecture with separate computing and memory units,which exposes the shortcomings of“memory bottleneck”.Nonvolatile memristor can realize data storage and in-memory computing at the same time and promises to overcome this bottleneck.Phase-change random access memory(PCRAM)is called one of the best solutions for next generation non-volatile memory.Due to its high speed,good data retention,high density,low power consumption,PCRAM has the broad commercial prospects in the in-memory computing application.In this review,the research progress of phase-change materials and device structures for PCRAM,as well as the most critical performances for a universal memory,such as speed,capacity,and power consumption,are reviewed.By comparing the advantages and disadvantages of phase-change optical disk and PCRAM,a new concept of optoelectronic hybrid storage based on phase-change material is proposed.Furthermore,its feasibility to replace existing memory technologies as a universal memory is also discussed as well.
基金supported by the National Key Research and Development Projects(No.2018YFC0808600)。
文摘A lithium-ion battery thermal management system has always been a hot spot in the battery industry. In this study, a novel high-thermal-conductivity composite phase-change material(CPCM) made by paraffin wax and silicon was adopted to facilitate heat transfer. Moreover, high resistance or even insulation of CPCM is capable of preventing short circuits between the cells. The heat transfer mechanism of CPCMs was determined under a scanning electron microscope. A thermogravimetric analyzer was employed to determine the thermal stability. A diff erential scanning calorimeter was used to explore the thermophysical properties of the composite samples. By comparing the results of the experiment, it was reported that under the silicon carbide content of 5%, the parameters were better than others. The phase-change enthalpy of CPCM was 199.4 J/g, the leakage rate of liquid was 4.6%, and the melting point was 53.6℃. To verify the practicality of CPCM, a three-dimensional layered battery pack model was built in the COMSOL Multiphysics software. By simulating the thermal runaway inside the battery packs of various materials, it was reported that the addition of CPCM significantly narrowed the temperature range of the battery pack from 300–370 to 303–304 K. Therefore, CPCM can eff ectively increase the rate of heat transfer to prevent the chain of thermal runaway reactions. It also enables the battery pack to run at a stable temperature.
基金Project supported by the Natural Science Foundation of Shaanxi Province,China(Grant No.2021JM466)
文摘Based on the phase-change material Ge_(2)Sb_(2)Te_(5)(GST),achromatic metasurface optical device in the longer-infrared wavelength is designed.With the combination of the linear phase gradient GST nanopillar and the adjustment of the crystalline fraction m value of GST,the polarization insensitive achromic metalenses and beam deflector metasurface within the longer-infrared wavelength 9.5μm to 13μm are realized.The design results show that the achromatic metalenses can be focused on the same focal plane within the working waveband.The simulation calculation results show that the fullwidth at half-maximum(FWHM)of the focusing spot reaches the diffraction limit at each wavelength.In addition,the same method is also used to design a broadband achromatic beam deflector metasurface with the same deflection angle of 19°.The method proposed in this article not only provides new ideas for the design of achromatic metasurfaces,but also provides new possibilities for the integration of optical imaging,optical coding and other related optical systems.
基金Project supported by the National Science and Technology Major Project of China(Grant No.2017ZX02301007-002)the National Key R&D Plan of China(Grant No.2017YFB0701701)the National Natural Science Foundation of China(Grant Nos.61774068 and 51772113).The authors acknowledge the support from Hubei Key Laboratory of Advanced Memories&Hubei Engineering Research Center on Microelectronics.
文摘Phase-change material(PCM)is generating widespread interest as a new candidate for artificial synapses in bioinspired computer systems.However,the amorphization process of PCM devices tends to be abrupt,unlike continuous synaptic depression.The relatively large power consumption and poor analog behavior of PCM devices greatly limit their applications.Here,we fabricate a GeTe/Sb2Te3 superlattice-like PCM device which allows a progressive RESET process.Our devices feature low-power consumption operation and potential high-density integration,which can effectively simulate biological synaptic characteristics.The programming energy can be further reduced by properly selecting the resistance range and operating method.The fabricated devices are implemented in both artificial neural networks(ANN)and convolutional neural network(CNN)simulations,demonstrating high accuracy in brain-like pattern recognition.
基金supported and funded by the Deanship of Scientific Research at Imam Mohammad Ibn Saud Islamic University(IMSIU)(Grant Number IMSIU-RG23098).
文摘Faced with the world’s environmental and energy-related challenges,researchers are turning to innovative,sustainable and intelligent solutions to produce,store,and distribute energy.This work explores the trend of using a smart sensor to monitor the stability and efficiency of a salt-gradient solar pond.Several studies have been conducted to improve the thermal efficiency of salt-gradient solar ponds by introducing other materials.This study investigates the thermal and salinity behaviors of a pilot of smart salt-gradient solar ponds with(SGSP)and without(SGSPP)paraffin wax(PW)as a phase-change material(PCM).Temperature and salinity were measured experimentally using a smart sensor,with the measurements being used to investigate the stabilizing effects of placing the PCM in the solar pond’s lower convective zone.The experimental results show that the pond with the PCM(SGSPP)achieved greater thermal and salinity stability,with there being a lesser temperature and salinity gradient between the different layers when compared to a solar pond without thePCM(SGSP).The use of the PCM,therefore,helped control the maximum and minimum temperature of the pond’s storage zone.The UCZ has been found to operate approximately 4 degrees above the average ambient temperature of the day in the SGSPP and 7 degrees in SGSP.Moreover,an unstable situation is generated after 5 days from starting the operation and at 1.9 m from the bottom,and certain points have the tendency to be neutral from the upper depths in 1,3 m of the bottom.
基金supported by National Natural Science Foundation of China(Grant Nos.52032004,51572104,51932003)National Key R&D Program of China(2016YFA0200400)+2 种基金National Major Project for Research on Scientific Instruments of China(2012YQ24026404)Fundamental Research Funds for the Central Universities(JLU)Program for JLU Science and Technology Innovative Research Team(JLUSTIRT,2017TD-09)。
文摘Ge2 Sb2 Te5 is the most widely utilized chalcogenide phase-change material for non-volatile photonic applications,which undergoes amorphous-cubic and cubic-hexagonal phase transition under external excitations.However,the cubic-hexagonal optical contrast is negligible,only the amorphous-cubic phase transition of Ge_(2)Sb_(2)Te_(5) is available.This limits the optical switching states of traditional active displays and absorbers to two.We find that increasing structural disorder difference of cubic-hexagonal can increase optical contrast close to the level of amorphous-cubic.Therefore,an amorphous-cubichexagonal phase transition with high optical contrast is realized.Using this phase transition,we have developed display and absorber with three distinct switching states,improving the switching performance by 50%.Through the combination of first-principle calculations and experiments,we reveal that the key to increasing structural disorder difference of amorphous,cubic and hexagonal phases is to introduce small interstitial impurities(like N)in Ge2 Sb2 Te5,rather than large substitutional impurities(like Ag)previously thought.This is explained by the formation energy and lattice distortion.Based on the impurity atomic radius,interstitial site radius and formation energy,C and B are also potential suitable impurities.In addition,introducing interstitial impurities into phase-change materials with van der Waals gaps in stable phase such as GeSb_(4) Te_(7),GeSb_(2) Te_(4),Ge_(3)Sb_(2) Te_(6),Sb_(2)Te_(3) will produce high optical contrast amorphous-metastable-stable phase transition.This research not only reveals the important role of interstitial impurities in increasing the optical contrast between metastable-stable phases,but also proposes varieties of candidate matrices and impurities.This provides new phase-change materials and design methods for non-volatile optical devices with multi-switching states.
基金supported in part by Beijing Natural Science Foundation Grant No.Z220006in part by the National Natural Science Foundation of China under Grant No.62304087。
文摘All-dielectric metasurface, which features low optical absorptance and high resolution, is becoming a promising candidate for full-color generation. However, the optical response of current metamaterials is fixed and lacks active tuning. In this work, we demonstrate a reconfigurable and polarization-dependent active color generation technique by incorporating low-loss phase change materials(PCMs) and CaF_2 all-dielectric substrate. Based on the strong Mie resonance effect and low optical absorption structure, a transflective, full-color with high color purity and gamut value is achieved. The spectrum can be dynamically manipulated by changing either the polarization of incident light or the PCM state. High transmittance and reflectance can be simultaneously achieved by using low-loss PCMs and substrate. The novel active metasurfaces can bring new inspiration in the areas of optical encryption, anti-counterfeiting, and display technologies.
文摘Today, latent heat storage technology has advanced to allow reuse of waste heat in the middle-temperature range. This paper describes an approach to develop a latent heat storage system using middle-temperature waste heat (~100oC - 200oC) from factories. Direct contact melting and solidification behavior between a heat-transfer fluid (oil) and a latent heat storage material mixture were observed. The mixture consisted of mannitol and erythritol (Cm = 70 mass %, Ce = 30 mass %) as a phase-change material (PCM). The weight of the PCM was 3.0 kg and the flow rate of the oil, foil, was 1.0, 1.5, or 2.0 kg/min. To decrease the solidified height of the PCM mixture during the solidification process, a perforated partition plate was installed in the PCM region in the heat storage vessel. PCM coated oil droplets were broken by the perforated partition plate, preventing the solidified height of the PCM from increasing. The solidification and melting processes were repeated using metal fiber. It was found that installing the metal fiber was more effective than installing the perforated partition plate to prevent the flow out problem of the PCM.
基金Supported by the Strategic Priority Research Program(B)of Chinese Academy of Sciences(XDB0580000,XDB43010200)National Natural Science Foundation of China(62222514,62350073,U2341226,61991440)+6 种基金National Key Research and Development Program of China(2023YFA1406900)Shanghai Science and Technology Committee(23ZR1482000,22JC1402900,22ZR1472700)Natural Science Foundation of Zhejiang Province(LR22F050004)Shanghai Municipal Science and Technology Major Project(2019SHZDZX01)Youth Innovation Promotion Association(Y2021070)and International Partnership Program(112GJHZ2022002FN)of Chinese Academy of SciencesShanghai Human Resources and Social Security Bureau(2022670)China Postdoctoral Science Foundation(2023T160661,2022TQ0353 and 2022M713261).
文摘Metasurfaces provide a potent platform for the dynamic manipulation of electromagnetic waves.Coupled with phase-change materials,they facilitate the creation of versatile metadevices,showcasing various tunable functions based on the transition between amorphous and crystalline states.However,the inherent limitation in tunable states imposes constraints on the multiplexing channels of metadevices.Here,this paper introduces a novel approach-a multi-functional metadevice achieved through the two-level control of the encoding phasechange metaatoms.Utilizing the phase-change material Ge_(2)Sb_(2)Se_(4)Te1(GSST)and high refractive-index liquid diiodomethane(CH_(2)I_(2)),this paper showcases precise control over electromagnetic wave manipulation.The GSST state governs the tunable function,switching it ON and OFF,while the presence of liquid in the hole dictates the deflection angle when the tunable function is active.Importantly,our tunable coding metasurface exhibits robust performance across a broad wavelength spectrum.The incorporation of high refractive-index liquid extends the regulatory dimension of the metadevice,enabling dynamic switching of encoding bit levels.This two-level tunable metadevice,rooted in phase-change materials,presents a promising avenue for the dynamic control of functions.
基金supported by the National Science Foundation(NSF)(Nos.CCF-2006788 and CNS-2046226)L.H.C.and J.Y.thank the support of Heising-Simons Faculty Fellowship.
文摘Integration of phase-change materials(PCMs)created a unique opportunity to implement reconfigurable photonics devices that their performance can be tuned depending on the target application.Conventional PCMs such as Ge-Sb-Te(GST)and Ge-Sb-Se-Te(GSST)rely on melt-quench and high temperature annealing processes to change the organization of the molecules in the materials’crystal.Such a reorganization leads to different optical,electrical,and thermal properties which can be exploited to implement photonic memory cells that are able to store the data at different resistance or optical transmission levels.Despite the great promise of conventional PCMs for realizing reconfigurable photonic memories,their slow and extremely power-hungry thermal mechanisms make scaling the systems based on such devices challenging.In addition,such materials do not offer a stable multi-level response over a long period of time.To address these shortcomings,the research carried out in this study shows the proof of concept to implement next-generation photonic memory cells based on two-dimensional(2D)birefringence PCMs such as SnSe,which offer anisotropic optical properties that can be switched ferroelectrically.We demonstrate that by leveraging the ultrafast and low-power crystallographic direction change of the material,the optical polarization state of the input optical signal can be changed.This enables the implementation of next-generation high-speed polarization-encodable photonic memory cells for future photonic computing systems.Compared to the conventional PCMs,the proposed SnSe-based photonic memory cells offer an ultrafast switching and low-loss optical response relying on ferroelectric property of SnSe to encode the data on the polarization state of the input optical signal.Such a polarization encoding scheme also reduces memory read-out errors and alleviates the scalability limitations due to the optical insertion loss often seen in optical transmission encoding.
基金supported by the Inner Mongolia Autonomous Region Science and Technology Plan Project(Grant No.2021GG0253)Inner Mongolia Autonomous Region Natural Science Foundation(Grant No.2024MS05044)+2 种基金Young Scientific and Technological Talent(Grant No.NJYT24012)Inner Mongolia Autonomous Region Scientific Research Projects of Universities(Grant No.JY20220110)Autonomous Region Science and Technology Plan Project(Grant No.2021ZD0036)。
文摘To address the intermittent challenges of new energy and waste heat recovery as well as counteract the issues of corrosion and overcooling in phase-change materials,this study develops and investigates a medium-temperature phase-change capsule(PCC)through experiments and numerical simulations.The thermal cycle stability testing of the developed PCC,subjected to 150 cycles to evaluate its performance,demonstrated that the capsule's surface remained intact with no signs of leakage.The enthalpy-porosity method combined with the volume-of-fluid method was used to establish a numerical model to simulate the phase-change process in capsules with two structures:one with a central cavity and the other with a top cavity.Results indicated that when using 304 stainless steel as the wall material for both structures,the PCC with the centrally located cavity melted28.3%faster than that with the cavity at the top.When using different materials as wall coverings,the melting rate of the PCC made of polytetrafluoroethylene(PTFE)was 22.1%slower than that of the capsule made of 304stainless steel.Conversely,the modified PTFE PCC melted 15.2%faster than the stainless steel-based PCC.Furthermore,when using PCCs having different diameters,the time differences for complete melting between the PTFE and stainless steel-based PCCs were 118 s and 66 s for the capsules having diameters of 24 mm and 16 mm,respectively,indicating that the time difference decreased with decreasing capsule diameter.
基金supported by the National Science and Technology Major Project of China(Grant No.2022ZD0117600)the National Natural Science Foundation of China under Grant No.12474230.
文摘Theoretical simulation of phase change materials such as Ge-Sb-Te has suffered from two methodological issues.On the one hand,there is a lack of efficient band gap correction method for density functional theory that is suitable for these materials in both crystalline and amorphous phases,while maintaining the computational complexity comparable to local density approximation.On the other hand,analysis of the coordination number in amorphous phases relies on an integration involving the radial distribution function,which adds to the complexity.In this work,we find that the shell DFT-1/2 method offers overall band gap accuracy for phase-change materials comparable to that of the HSE06 hybrid functional,while its computational cost is orders of magnitude lower.Moreover,the mixed length-angle coordination number theory enables calculating the coordination numbers in the amorphous phase directly from the structure,with definite outcomes.The two methodologies could be helpful for high-throughput simulations of phase change materials.
基金National Natural Science Foundation of China(U23A20377)Postgraduate Education Reform and Quality Improvement Project of Henan Province(YJS2024JD32)POSCO(POSCO-POSTECH-RIST Convergence Research Center)National Research Foundation of Korea(RS-2022-NR067559)。
文摘In complex environments,infrared camouflage within the long-wave infrared range is essential for modern defense and surveillance applications,requiring precise control over both radiative and scattering properties of military targets.For practical implementation,developing surfaces that integrate dynamic emissivity control,low specular reflectance,and scalable fabrication processes remains a significant challenge.Here,a novel infrared camouflage device is proposed to simultaneously achieve low specular reflectance(<0.1)and dynamic infrared camouflage.The device seamlessly blends into backgrounds with temperatures ranging from 35°C to 45°C by tuning the emissivity of the device,which is attained by controlling the Ge2Sb2Te5 phase change.In addition,it reflects almost no surrounding thermal signals compared with the conventional low-emissivity smooth surface.The thermal camouflage remains effective and stable across observation angles ranging from 20°to 60°.This work proposes a novel approach to simultaneously reducing specular reflection and dynamic emissivity control,potentially inspiring future research and applications in multispectral camouflage and stealth technology.
基金financially supported by the National Natural Science Foundation of China (21875261, 51925307 and 21733010)the National Key Research and Development Program of China (2020YFE0100300 and 2018YFA0208502)+1 种基金the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (ZDBS-LYSLH031)the Youth Innovation Promotion Association of the Chinese Academy of Sciences (2018044)。
文摘Solar anti-icing/de-icing is an environmentally friendly way to convert light energy into heat with the purpose of melting/removing ice. However, the inherent intermittency of solar irradiation limits the application of solar-thermal energy-conversion technologies, when continuous de-icing is required. Herein, we investigate a solar phase-change material(SPCM) that consists of expanded graphite(EG)/paraffin/polydimethylsiloxane(PDMS), which can not only perform the solar-thermal conversion but also release/store thermal energy. Under sunlight, the SPCM effectively collects and converts the light energy into thermal energy for later antiicing/de-icing. To prepare for a no-light period, e.g., in the evening, the converted thermal energy can be stored in the SPCM using a phase transition. In this way, the energy can be released when needed to keep the temperature of a surface from freezing. The SPCM surface shows excellent anti-icing/de-icing properties such as a long droplet freeze-delay time(td> 2 h), even at an ultra-low temperature(-40℃), using only the light of one sun. This freeze-delay time is much longer than that for a surface without PCM. The tested SPCM surfaces show a high de-icing rate(2.21 kg m^(-2)h^(-1)) under real-life conditions. In addition, the SPCM shows a high de-icing rate and excellent durability. This study provides a promising route for the utilization of solar energy in anti-icing/de-icing applications.
基金973 Program of China(2013CB632704)National Natural Science Foundation of China(NSFC)(11374357,11434017)
文摘We numerically demonstrate a novel ultra-broadband polarization-independent metamaterial perfect absorber in the visible and near-infrared region involving the phase-change material Ge_2Sb_2Te_5(GST).The novel perfect absorber scheme consists of an array of high-index strong-absorbance GST square resonators separated from a continuous Au substrate by a low-index lossless dielectric layer(silica)and a high-index GST planar cavity.Three absorption peaks with the maximal absorbance up to 99.94% are achieved,owing to the excitation of plasmon-like dipolar or quadrupole resonances from the high-index GST resonators and cavity resonances generated by the GST planar cavity.The intensities and positions of the absorption peaks show strong dependence on structural parameters.A heat transfer model is used to investigate the temporal variation of temperature within the GST region.The results show that the temperature of amorphous GST can reach up to 433 K of the phase transition temperature from room temperature in just 0.37 ns with a relatively low incident light intensity of 1.11×10~8W∕m^2,due to the enhanced ultra-broadband light absorbance through strong plasmon resonances and cavity resonance in the absorber.The study suggests a feasible means to lower the power requirements for photonic devices based on a thermal phase change via engineering ultra-broadband light absorbers.
基金the support from the National Research Foundation,Prime Minister’s Office,Singapore under its Competitive Research Program (CRP Award No.NRF-CRP10-2012-04)funding from the Leverhulme trust and the EPSRC Active Plasmonics Programm+1 种基金funding provided by the 973 Program of China (No.2013CBA01700)the Chinese Natural Sciences Grant (61138002 and 61307043)
文摘A tunable plasmonic perfect absorber with a tuning range of 650 nm is realized by introducing a 20 nm thick phase-change material Ge2Sb2Te5 layer into the metal–dielectric–metal configuration.The absorption at the plasmonic resonance is kept above 0.96 across the whole tuning range.In this work we study this extraordinary optical response numerically and reveal the geometric conditions which support this phenomenon.This work shows a promising route to achieve tunable plasmonic devices for multi-band optical modulation,communication,and thermal imaging.
