Indium Tin Oxide Research Articles

Photolytic decomposition of PFOS by electrospun nanofiber composites of Fe(III)/PVDF Under UV-C light

Per- and polyfluoro alkyl substances (PFAS) are emerging pollutants that have contaminated various water streams of the world. Besides polluting the environment, it is related to several human diseases, including cancer. Various methods have been proposed to remove PFAS from water streams including, photocatalytic or photolytic decomposition of PFAS which decomposes PFAS in a quasi-perpetual fashion and does not generate secondary pollution. In this work, perfluoroctane sulfonic acid (PFOS) is used as a model PFAS to study its photolytic decomposition by nanofiber composites (NFC) of Fe (III) and polyvinylidene fluoride (PVDF) under ultraviolet (UV)-C light. The nanofiber composite was fabricated using an electrospinning technique with PVDF and iron precursor on the conductive surface of indium tin oxide (ITO) coated polyethylene terephthalate (PET) film. The composite was characterized with SEM-EDX, AFM, XRD, and TGA. It was found that a significant amount, 70 % of aqueous PFOS solution is decomposed by the composites in the presence of traces of hydrogen peroxide and UV-C light. The kinetics of PFOS degradation was fit with pseudo-first order rate constant of 0.056 hr−1. It is proposed that PFOS binds with Fe(III) to form an unstable complex that is decomposed under UV-C light and Fe(III) is reduced Fe(II). Hydrogen peroxide provides the simultaneous benefits of further decomposing the PFOS complex and regenerating Fe(III). The overall results suggest that this nanofiber composite can be used for the photolytic decomposition of PFOS. It is also revealed that two composite mats showed the optimal performance and the increase in concentration of hydrogen peroxide increased the degradation of PFOS monotonically.

Application of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) based on multiple treatments with hot alcohol solvents in organic solar cells

Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) materials are widely used to replace common indium tin oxide (ITO) transparent electrodes. However, the conductivity of untreated PEDOT:PSS is unsatisfactory. Thus, enhancing the conductivity of PEDOT:PSS has become an urgent task. In this study, we use hot methanol, 2-methoxyethanol, and ethanol to treat PEDOT:PSS films and explore the effect of multiple treatments with hot alcohol solvents on the electrical conductivity of the films. Results show that the conductivity of the PEDOT:PSS films gradually were increased to 2538 S cm−1, 2273 S cm−1 and 1361 S cm−1 after in the number of treatments using methanol, 2-methoxyethanol and ethanol, respectively. The measurement of absorption for the PEDOT:PSS films before and after treatment revealed that the nonconducting PSS components were effectively removed from the PEDOT:PSS materials using the hot alcohol solvent treatment, which led to the exposure of the PEDOT chains to induce the formation of polaritons (PEDOT+) or bipolaritons (PEDOT2+) and thus enhanced the conductivity of the films. The figure of merit (FoM) values after six times treatments with methanol and 2-methoxyethanol were as high as 56.87 and 51.61, respectively. The FoM of ethanol was 33.58, which did not meet the minimum criteria for commercial application. PEDOT:PSS films treated using methanol and 2-methoxyethanol were applied as transparent electrodes in organic solar cells with power conversion efficiency values of 2.14% and 2.05%, respectively, which reached 87.35% and 83.67% for ITO-based transparent electrodes (2.45% for pure ITO).

In Situ Live Monitoring of Extracellular Acidosis near Cancer Cells Using Digital Microfluidics with an Integrated Optical pH Sensor Film.

We demonstrate the live monitoring of extracellular acidification on digital microfluidics using a chip-integrated fluorescent pH sensor film. The metabolism of various types of live cells including cancer and healthy cells were investigated through recording the extracellular pH (pHe) change. An optical pH sensor array was integrated onto a digital microfluidic (DMF) interface with a diameter of 2 mm per pH-sensing spot. Miniaturized, label-free, and noninvasive monitoring of extracellular acidosis on DMF was realized within a pH range of 5.0-8.0 with good sensitivity and rapid response. The pH sensitive probe fluorescein-5-isothiocyanate was covalently bound to poly-2-hydroxyethyl methacrylate and immobilized on a circularly exposed indium tin oxide interface on the DMF top plate. The surface of the fabricated pH sensor spots was modified with polydopamine via self-polymerization. Direct cell attachment on the sensor surfaces enabled rapid pH detection near the cell membranes. Automatic medium exchange on cell-attached pH sensing sites was achieved though solution passive dispensing on DMF. The developed DMF platform was used to monitor the pHe decrease during MCF-7 and A549 cancer cell proliferation due to abnormal glycolysis metabolism. A rapid pH decrease at the pH sensing area in the presence of cancer cells could be detected within 2 min after fresh medium exchange, while no obvious pHe change was observed with HUVEC healthy cells. Real-time detection of cell acidification and cellular response to different metabolic conditions such as higher glucose levels or administered anticancer drugs was possible.

Bayesian Optimization of Low-Temperature Nonthermal Plasma Jet Sintering of Nanoinks.

In response to the escalating demand for flexible devices in applications such as wearables, sensors, and touch panels, there is a need for innovative fabrication approaches for devices made from nanomaterial-based inks. Subsequent to ink deposition, a pivotal stage in device manufacturing typically involves high-temperature sintering, posing challenges for heat-sensitive substrates. Nonthermal plasma jet sintering utilizing an atmospheric pressure dielectric barrier discharge (DBD) plasma jet enables sintering at room temperature and standard pressure, facilitating the sintering of printed nanoparticle films without compromising substrate or film surface integrity. However, determining optimal plasma jet sintering conditions can be challenging due to multiple processing variables with intricate interrelationships. This work employed Bayesian optimization (BO) and machine learning (ML) to identify optimal values for seven primary plasma jet sintering variables. Optimization yielded a 99.2% increase in the measured electrical conductivity for plasma jet-sintered indium tin oxide (ITO) films after five rounds of experiments. Moreover, the optimal sintering conditions achieved an electrical conductivity that was 81.4% of conventional furnace sintering at 300 °C, but was three times faster and with a peak substrate temperature below 47 °C. This result demonstrates the prospect of applying BO to optimize processing techniques for emerging low-temperature requirements.

Wideband optically transparent absorber based on multilayer ITO films with high absorption rate

In this paper, a wideband optically transparent absorber based on multilayer indium tin oxide (ITO) films is designed, fabricated, and measured. The structure uses polyethylene terephthalate (PET) and ITO films to replace the dielectric substrate and metal pattern of the traditional absorber to achieve optical transparency characteristics. The absorption of the proposed absorber is above 90% from 4.92 to 24.55 GHz and exceeding 95% in the range of 5.74 ∼ 21.85 GHz, respectively, under normal transverse electric (TE) and transverse magnetic (TM) polarized incidences. Moreover, it shows outstanding stability with various incident angles over a wide range. A prototype of the proposed absorber is fabricated and experimentally verified, with good measurement results. The optical transparency and great absorption performance make the absorber a promising candidate for transparent electromagnetic compatibility.

Mechanical reconfigurable infrared filter for stress sensing applications

In this study, we introduce a novel tunable infrared filter design aimed at stress sensor applications such as health monitoring, advanced robotics and industrial automation. The design utilizes a double-layer plasmonic frequency-selective surface (FSS) of indium tin oxide (ITO) with an aerogel inter-space region. The unique feature of this design is its ability to control the transmission pattern based on the stress exerted, which alters the distance between the two filter layers. Our approach employs both numerical simulations and a simplified model grounded in equivalent circuit theory and the transfer matrix method for accurate transmission pattern estimation where the sensor achieved a sensitivity of 20nm/MPa for average stress of 14MPa and spectrum range (λ>800nm\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\lambda >800 nm$$\\end{document}). The work provides an in-depth analysis of how layer dimensions and inter-layer distance influence both transmission and force, taking into account the elastic properties of the inter-space material.

Realizing record efficiencies for ultra‐thin organic photovoltaics through step‐by‐step optimizations of silver nanowire transparent electrodes

AbstractUltra‐thin (also known as ultra‐flexible) organic photovoltaics (OPVs) represent a strong contender among emerging photovoltaic technologies. However, due to the imbalance between the optical and electrical properties of indium tin oxide (ITO)‐free transparent electrodes, the ultra‐thin OPVs often exhibit lower efficiency compared to the brittle yet more balanced rigid ITO counterparts. Here, we design and fabricate an advanced ultra‐thin OPV, which involves a thoroughly optimized silver nanowires (AgNWs) transparent electrode (named AZAT) with excellent optical, electrical and mechanical properties. Specifically, the high‐kinetic energy spray‐coating method successfully yields a curve‐shaped, tightly connected and uniformly distributed AgNWs film, complemented by a capping layer of zinc oxide:aluminum‐doped zinc oxide (ZnO:AZO) to improve charge collection capability. Simultaneously, the transparency of the electrode is enhanced through precise optical optimization. Thus, we implant the AZAT‐based devices on 1.3 μm polyimide substrates and demonstrate ultra‐thin OPVs with a record efficiency of 18.46% and a power density of 40.31 W g−1, which is the highest value for PV technologies. Encouragingly, the AZAT electrode also enables the 10.0 cm2 device to exhibit a high efficiency of 15.67%. These results provide valuable insights for the development of ultra‐thin OPVs with high efficiency, low cost, superior flexibility, and up‐scaling capacity.

SERS aptasensor for simultaneous detection of ochratoxin A and zearalenone utilizing a rigid enhanced substrate (ITO/AuNPs/GO) combined with Au@AgNPs

The contamination of mycotoxins poses a serious threat to global food security, hence the urgent need for simultaneous detection of multiple mycotoxins. Herein, two SERS nanoprobes were synthesized by embedded SERS tags (4-mercaptopyridine, 4MPy; 4-mercaptobenzonitrile, TBN) into the Au and Ag core–shell structure, and each was coupled with the aptamers specific to ochratoxin A (OTA) and zearalenone (ZEN). Meanwhile, a rigid enhanced substrate Indium tin oxide glass/AuNPs/Graphene oxide (ITO/AuNPs/GO) was combined with aptamer functionalized Au@AgNPs via π-π stacking interactions between the aptamer and GO to construct a surface-enhanced Raman spectroscopy (SERS) aptasensor, thereby inducing a SERS enhancement effect for the effective and swift simultaneous detection of both OTA and ZEN. The presence of OTA and ZEN caused signal probes dissociation, resulting in an inverse correlation between Raman signal intensity (1005 cm−1 and 2227 cm−1) and the concentrations of OTA and ZEN, respectively. The SERS aptasensor exhibited wide linear detection ranges of 0.001–20 ng/mL for OTA and 0.1–100 ng/mL for ZEN, with low detection limits (LOD) of 0.94 pg/mL for OTA and 59 pg/mL for ZEN. Furthermore, the developed SERS aptasensor demonstrated feasible applicability in the detection of OTA and ZEN in maize, showcasing its substantial potential for practical implementation.

Highly Transmissive, Processable, Highly Conducting and Stable Polythiophene Derivatives via Direct (Hetero)arylation Polymerization.

The development of modern optoelectronic devices increases the need for lightweight and flexible transparent conductors. It is thus essential to develop new eco-friendly materials that can be easily processed for the fabrication of such devices. For this purpose, the synthesis of self-doped, highly conducting, transmissive, and water-processable polythiophene derivatives was performed via the direct heteroarylation polymerization method and a protection/deprotection strategy. Stable conductivities up to 1000 S cm-1 have been obtained. Champion materials (P1 and P7) were scaled and processed via the roll-to-roll compatible slot-die coating method to demonstrate their large area applicability. The best coated films exhibited optical transmittance greater than 79% at 550 nm with sheet resistances of 116 Ω □-1. These values are comparable to indium-tin oxide on plastic and thus present a viable alternative to metal oxide-based electrodes.

Quantum Interference at the Recombination Junction of Perovskite-Si Tandem Solar Cells Improves Efficiency.

We show quantum interference effects can enhance coherent electron transmission in perovskite tandem solar cells using ultrathin indium tin oxide (ITO) layers. We develop a model for the behavior of the power conversion efficiency based on a finite difference time domain solution of the time-dependent Schrödinger equation. The modeled potential includes an imaginary part to simulate probability loss by incoherent scattering. The results agree with observations of efficiency as a function of ITO thickness, suggesting an optimized design.

Single CsPbBr3 Perovskite Microcrystals: From Microcubes to Microrods with Improved Crystallinity and Green Emission.

All-inorganic perovskite materials are promising in optoelectronics, but their morphology is a key parameter for achieving high device efficiency. We prepared CsPbBr3 perovskite microcrystals with different shapes grown directly on planar substrate by conventional drop casting. We observed the formation of CsPbBr3 microcubes on bare indium tin oxide (ITO)-coated glass. Interestingly, with the same technique, CsPbBr3 microrods were obtained on (3-Aminopropyl) triethoxysilane (APTES)-modified ITO-glass, which we ascribe to the modification of formation kinetics. The obtained microcrystals exhibit an orthorhombic structure. A green photoluminescence (PL) emission is revealed from the CsPbBr3 microrods. Contact angle measurements, Fourier-transform infrared and PL spectroscopies confirmed that APTES linked successfully to the ITO-glass substrate. We propose a qualitative mechanism to explain the anisotropic growth. The microrods exhibited improved PL and a slower PL lifetime compared to the microcubes, likely due to the diminished occurrence of defects. This work demonstrates the importance of the substrate surface to control the growth of perovskite single crystals and to boost the radiative recombination in view of high-performance optoelectronic devices.

Electrochemical Charge Transfer Kinetics of Ferrocene in the Light of Different Working Electrodes.

Ferrocene is an accidentally discovered organometallic compound that serves as a crucial redox probe in investigating electrochemical charge transfer dynamics. Besides solution phase studies, ferrocene derivatives are well-explored in molecular thin films, including self-assembled monolayers on various electrodes for understanding on-surface redox behavior, molecular electronics, and charge storage applications. Heterogeneous charge transfer is an imperative parameter for efficient charge transport in spin-dependent electrochemistry, photoelectrochemistry, and molecular electronic devices. In this work, we aim to study the electrochemical charge transfer of ferrocene on various electrodes such as commercially obtained glassy carbon, graphite rod, indium tin oxide (ITO), and as-prepared gold, and nickel to determine the impact of the nature of the working electrode on the electron transfer rate, diffusion coefficient, and reversibility of the redox process. Both the direct current and alternating current-based electrochemical experiments are performed, followed by digitization of the experimental results. The kinetics of electron transfer and electrochemical reversibility reveal a strong dependence on the nature of the working electrode, as the electrochemically driven oxidation and reduction of the material of interest are directly related to the Fermi energy and electronic structure of the working electrode.

Preparation and performance of graphene-doped indium tin oxide coatings on titanium bipolar plate surface

To enhance the corrosion resistance of titanium bipolar plates, indium tin oxide (ITO) coatings doped with varying quantities of graphene were fabricated using the sol-gel method. The coatings' surface morphology and microstructure were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The hydrophobicity of the coatings was evaluated using a contact angle goniometer, and their corrosion resistance in a simulated proton exchange membrane fuel cell (PEMFC) corrosion solution (0.5 mol/L H2SO4 + 2 mg/L HF) was measured using an electrochemical workstation. The findings revealed that increasing graphene doping resulted in a more uniform, smooth, and dense coating surface. The ITO coating primarily consisted of In2O3. However, with graphene doping, diffraction peaks of the InOCl phase appeared, indicating changes in the material's composition and structure. Additionally, the valence peaks of the main elements shifted, reflecting alterations in their chemical states. Graphene doping significantly enhanced the coating's hydrophobicity compared to the undoped ITO coating. The water contact angle of the ITO coating with 0.375 g/L graphene increased from 104° to 126°. Furthermore, this graphene-doped coating demonstrated superior corrosion resistance, with a corrosion current density of 0.06 μA/cm2, representing a decrease by three orders of magnitude compared to the titanium substrate. Additionally, it exhibited the largest capacitive arc radius, indicating enhanced charge transfer resistance and better overall electrochemical stability.

Enhanced humidity sensing properties of Ta2O5 and ITO doped rutile-TiO2 porous ceramics

In this study, we investigated the humidity sensing properties of TiO2-based ceramics doped with tantalum pentoxide (Ta2O5) and indium tin oxide (ITO). Pure TiO2, 1%Ta-doped TiO2 (1%TTO), 1%ITO-doped TiO2 (1%ISTO), and 1%(Ta2O5 + ITO) co-doped TiO2 (1%ISTTO) ceramic samples were obtained by sintering at 1200 °C for 3 h. The rutile phase was observed in all samples. The lattice parameters of the single and co-doped samples were larger than those of pure TiO2, confirming the substitution of dopants. Porosity was observed in all ceramics. The mean grain sizes of all doped samples were significantly reduced compared to undoped TiO2. A homogeneous element dispersion was observed in the 1%TTO and 1%ISTTO ceramics, while segregation particles of related In-rich elements was observed in the 1%ISTO ceramic. Giant dielectric properties were not achieved in any samples due to the porosity. Nevertheless, excluding the undoped TiO2, the dielectric properties of all porous ceramics varied significantly with changes in humidity. The 1%ISTTO ceramic demonstrated superior humidity sensing properties, including a low maximum hysteresis error of 3.6% at 102 Hz. In contrast, the 1% TTO and 1% ISTO ceramics showed higher maximum hysteresis errors of 7.2% and 19.8%, respectively. Notably, the response and recovery times were 7.05 ± 0.18 and 2.48 ± 0.39 min, respectively, with good repeatability. This improvement is likely due to the synergistic effect of oxygen vacancies and TaTi·\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{Ta}}_{{{\ ext{Ti}}}}^{ \\cdot }$$\\end{document} defects on the surface, enhancing the humidity sensing properties of the 1% ISTTO ceramic, coupled with its optimal microstructure due to its lowest porosity and grain size.

Potential for multi-application advancements from doping zirconium (Zr) for improved optical, electrical, and resistive memory properties of zinc oxide (ZnO) thin films

Transition metal-doped Zinc oxide (ZnO) thin films with an optimal wide band gap and semiconducting nature find numerous applications in optoelectronic devices, gas sensors, spintronic devices, and electronics. In this study, Zirconium (Zr) doped ZnO thin films were deposited on ITO (Indium Tin oxide) coated glass substrate using RF-magnetron sputtering. Optical and electrical properties were examined for their potential use in resistive random-access memory (RRAM) applications. X-ray Diffraction (XRD), UV–vis spectroscopy, x-ray photoelectron spectroscopy (XPS), Atomic force microscopy (AFM) and Scanning electron microscopy (SEM) were used to investigate structural, optical, and compositional properties and roughness respectively. The results demonstrate that the films possess crystalline properties. Additionally, an augmentation in Zr concentration correlates with an elevation in the optical band gap, ascending from 3.226 eV to 3.26 eV, accompanied by an increase in Urbach energy from 0.0826 eV to 0.1234 eV. The film with the highest Zr content among all the films demonstrated the best electrical performance for resistive memory applications. Incorporating Zr as a dopant shows enhancement in the electrical performance and such ZnO films with optimum concertation of Zr can potentially be used in RRAM. ZnO being a versatile host material, its doping with Zr may extend its applications in catalysis, gas sensing, energy storage, and biomedical engineering. ZnO thin films employ zirconium (Zr) as a dopant, which is a novel way to improve the material’s characteristics. Although ZnO has been thoroughly researched, adding Zr presents a novel technique to enhance optical, electrical, and resistive memory characteristics all at once that has not been fully investigated.

Nanoengineered multiwalled carbon nanotube for lung cancer diagnosis

In present work, we have nanoengineered multiwalled carbon nanotubes with magnesium oxide (MgO@f-MWCNT) and the obtained nanoengineered material has been used for the development of immunosensor for the diagnosis of early stage secreted lung cancer biomarker (Cytoskeleton-Associated Protein 4; CKAP4). The nanoengineered material (MgO@f-MWCNT) has been synthesized through optimized hydrothermal condition (170 °C, 17 h) and chemically functionalized using 3-aminopropyl triethoxysilane (APTES). The amine functionalized material (APTES/MgO@f-MWCNT) has been further deposited onto the indium tin oxide (ITO) coated glass electrode through optimized electrophoretic condition (60 V, 90 s). Further, EDC-NHS chemistry has been used to covalently immobilize anti-CKAP4 over electrode (APTES/MgO@f-MWCNT/ITO) and drop-cast method has been utilized to immobilize bovine serum albumin (BSA) to block non-specific sites. Through employing various techniques such as X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and cyclic voltammetry (CV) have been used to characterize, synthesize as well as functionalize nanoengineered material and the fabricated electrodes. Additionally, the CV technique has been used to conduct the electrochemical characterization and electrochemical response of fabricated biosensor (BSA/anti-CKAP4/APTES/MgO@f-MWCNT/ITO). This developed biosensor having ability to detect CKAP4 biomarker with linear range in between 6.25–500 pg mL−1, lower limit of detection of 6.25 pg mL−1 and in addition to sensitivity of 56.8 μA [log (pg mL−1)]−1cm−2. Moreover, electrochemical response of CKAP4 (concentration measured by enzyme-linked immunosorbent assay) identified in lung cancer patients has been also analyzed to validate the response of developed biosensor and the obtained results demonstrated a strong correlation with that of standard samples.

Fabrication of PSCs with light absorption chips utilizing double-metal-cladding waveguide technology

Metal nanoparticles or periodic metal nanostructures exhibit localized surface plasmon resonance (LSPR) effects, widely employed in photovoltaic devices to enhance the light absorption. In this study, we used a double-metal-cladding waveguide (DMCW) structure to fabricate hexagonal metal nanostructures on the front side of the indium tin oxide (ITO) glass, positioned away from the incident light direction. We then prepared perovskite solar cells under various reaction conditions. The analysis results indicate that the metal nanostructure chip excites near-field coupling, generating strong localized fields, and enhances the light absorption through the LSPR effect. The perovskite solar cells (PSCs) with the chip structures exhibited a significant increase in short-circuit current density (JSC) and fill factor (FF), accompanied by a decrease in dark current, indicating improved photovoltaic characteristics of the cells. Altering the evaporative deposition time of the silver film and the concentration of the reaction solution led to a 12.79% increase in the power conversion efficiency (PCE) of the PSCs.

Nanochannel-confined platinum nanostructure for enhancement of luminol-dissolved oxygen electrochemiluminescence coupled with gated aptasensor for sensitive detection of carcinoembryonic antigen

Rapid and precise detection of tumor biomarkers in serum is of great significance for early diagnosis, treatment assessment, and recurrence monitoring of cancers. The fabrication of user-friendly electrochemiluminescence (ECL) aptasensors with effective signal amplification is highly desirable. In this study, an ECL aptasensor was developed with luminol-based ternary ECL platform using dissolved oxygen as endogenous co-reactant and nanochannel-confined platinum nanoparticles (PtNPs) as co-reactant promoter, which can realize highly sensitive detection of the tumor biomarker, carcinoembryonic antigen (CEA). On the cost-effective indium tin oxide (ITO) electrode, amino-modified vertically-ordered mesoporous silica film (NH2-VMSF) was easily grown to form high-density nanochannel array with ultrasmall nanochannels. PtNPs were then in-situ synthesized within the nanochannels via electrodeposition. Ternary ECL system was successfully fabricated as confined PtNPs can catalyze the electroreduction of dissolved oxygen at negative potentials as well as electrochemical oxidation of luminol, enhancing the ECL signal of luminol. The recognitive aptamer (Apt) was covalently immobilized on the outer surface of NH2-VMSF, resulting in the fabrication of an aptasensor. In presence of CEA, a decreased ECL signal was obtained as the formed complex on the recognition interface hindered the diffusion of ECL emitter to the supporting electrode. Based on this signal turn-off mode, sensitive detection of CEA was achieved ranged from 10 fg mL−1 to 100 ng mL−1, with a low detection limit (DL, 0.4 fg mL−1). The aptasensor displayed high selectivity and good reproducibility. The nanochannel-based aptasensor and ternary ECL system demonstrates great potential in convenient and sensitive detection of cancer biomarker.

Genetic algorithm-enabled on-demand co-design of optically transparent metamaterial for multispectral stealth applications

This paper proposes a genetic algorithm (GA)-enabled co-design method for the development of metamaterials with on-demand microwave reflectivity and infrared (IR) emissivity. First, we proposed a multilayered metamaterial based on metasurface with hexagonal patch and ring patterns. An equivalent circuit model (ECM) was then established to model the microwave reflectivity of the metamaterial. To achieve broadband low microwave reflectivity, a GA based on this ECM was adopted to optimize the structural parameters of the metamaterial. A co-design task was accomplished by setting a judgment condition in the algorithm for low IR emissivity. With the help of GA, a metamaterial with broadband low microwave reflectivity and low IR emissivity was designed. Subsequently, a prototype metamaterial was fabricated by patterning optically transparent indium tin oxide films. The calculated, simulated, and measured results agreed well. The co-designed metamaterial had an IR emissivity of 0.15 within the spectral range of 3–14 µm, −10 dB microwave reflectivity at frequencies of 3.1–32.2 GHz, and transparency in the visible band. The proposed co-design method will benefit the design and application of multispectral stealth metamaterials.

Design of a dynamically switchable metamaterial solar heating and daytime radiative cooling device based on reversible metal electrodeposition

Abstract The combination of daytime radiative cooling and solar heating can regulate the temperature of buildings in all seasons, which is vital to achieving energy savings. However, achieving a dynamic and efficient switch between radiative cooling and solar heating states is still challenging. The reversible metal electrodeposition is a promising electrochromic (EC) technology that can dynamically manipulate the visible and infrared spectrum by depositing a nanoscale metal layer. By combining it with a delicate nanostructure design, reconfigurable daytime radiative cooling and solar heating states can be achieved. In this work, a metamaterial EC device capable of efficiently switching between high solar reflectance (91.73%) and high solar absorptance (95.41%) via reversible silver layer electrodeposition has been developed. This device consists of a top layer, which is a visible transparent electrode of indium tin oxide covered with an ultrathin platinum film, an electrolyte in the middle, and a metamaterial absorber based on a metal/dielectric multilayered structure at the bottom. Afterward, we analyze the spectrum of each part of the device and carry out a parametric study on the practical performance with different ambient temperatures and convective heat transfer coefficients. The average solar reflectance of the device in the radiative cooling state is 93.41% within the range of 0.3–2.5 μm. In the solar heating mode, the average solar absorptance of the device reaches 95.46%. Numerical simulations show that the device in the cooling mode achieves a temperature drop of 5 °C–9.8 °C and an average cooling power of 140.8 W m − 2 . The device in heating mode achieves a maximum temperature rise of 45 °C and a maximum heating power of 700 W m − 2 . This work provides a feasible design for solar heating and daytime radiative cooling switching devices, which is promising in applications like energy-saving buildings, wearable devices, electric vehicles and other outdoors facilities.