Indium Tin Oxide Polyethylene Terephthalate Research Articles

An ultrasensitive and disposable electrochemical aptasensor for prostate-specific antigen (PSA) detection in real serum samples.

In this study, we constructed a disposable indium tin oxide polyethylene terephthalate film (ITO-PET)-based electrochemical aptasensor for analyzing prostate-specific antigen (PSA), one of the most important biomarkers of prostate cancer. Because of their clinical importance, building PSA biosensing systems with high sensitivity and stability is essential. However, it still presents significant difficulties, such as low detection limits. We designed a platform to covalently bind the amino-terminated aptamer by modifying the ITO-PET surface with carboxyethylsilanetriol (CTES) to obtain a self-assembled monolayer (SAM). We also evaluated the potential for use in real human serum samples by investigating the optimal operating conditions and analytical performance characteristics of the developed biosensor. The design we present here exhibits excellent precision, with a limit of detection (LOD) as low as 8.74 fg/mL PSA. The broad linear detection range of the biosensor under optimal conditions was determined as 1.0-1500 fg/mL. The dissociation constant (Kd) for the aptamer was also calculated as 46.28 ± 5.63 nM by evaluating the impedimetric response as a function of PSA concentration. The aptasensor displayed considerable repeatability (1.3% RSD) and reproducibility (7.51% RSD) and good storage stability (98.34% of the initial activity for 8 weeks). Additionally, we demonstrated that the technique we developed was quite efficient in estimating the kinetics of aptamer-analyte interactions by determining the Kd and single-frequency impedance (SFI) data. In conclusion, we proposed a selective and sensitive biosensor with the potential for clinical application and superior performance in real serum samples.

Dielectric Behaviour of PVP 360 and PVA for Thin Flexible Transistors Application

Despite important progress in the field of the thin flexible transistor (TFT)-based electronics, a major challenge still exist for organic TFTs to decrease the operating voltage, which is related to the properties of the dielectric and semiconductor layers from the OTFTs structure. In this paper, we present the electrical behavior of two biocompatible polymers, polyvinylpyrrolidone (PVP 360) and polyvinyl alcohol (PVA), regarding the application as insulating layer in thin-film transistors. The PVA and PVP 360 thin films were deposited onto epoxy resin copper double-sided layer and polyethylene tere-phthalate/Indium tin oxide (PET/ITO) substrates by sol-gel method, spin-coating technique. Two sol concentrations (1 and 5 wt. %) were prepared and the contact angle onto the used substrates was measured using a digital microscope camera. The obtained films have been characterized by scanning electron microscopy (SEM) and dielectrical behaviour. For electrical measurements, the metal-insulating-metal (MIM) structure was realized by cooper electrodes deposition at room temperature, onto the top of thin films, by magnetron sputtering method. The current (I) - applied voltage (from -5 to +5 V) curves were measured in air at room temperature (RT), using the Picoammeter homemade device. PVA and PVP 360 thin films showed low leakage currents with values within � 2 nA for �5 V range.

Layer‐by‐Layer 2D Ultrathin Conductive Cu3(HHTP)2 Film for High‐Performance Flexible Transparent Supercapacitors

Abstract2D conductive metal–organic frameworks (2D c‐MOFs) naturally possess high active sites, large specific surface areas, and fast ion transport for energy‐storage devices. However, the intelligent exploration of 2D c‐MOFs for the emerging flexible transparent supercapacitors (FTSCs) with excellent photoelectric property and electrochemical activity is rarely implemented. Herein, 2D conductive ultrathin Cu3(HHTP)2 (HHTP = 2,3,6,7,10,11‐hexahydroxytriphenylene) film is synthesized on the indium tin oxide/polyethylene terephthalate (ITO/PET) substrate for flexible transparent conductive electrodes (FTCEs) through the layer‐by‐layer assembly method. The interconnected conductive frameworks possess the cooperative superiority of low internal resistance, fast electrolyte ion diffusion, and quick electron transfer. Cu3(HHTP)2‐15/ITO/PET FTCEs show high photoelectric property of T550 nm = 82.2% and Rs = 49.1 Ω sq−1, and high areal capacitance (CA) of 1700 µF cm−2. The corresponding symmetrical FTSCs (T550 nm = 62.1%) exhibit excellent CA of 939.2 µF cm−2 at the current density of 7 µA cm−2, superior rate capability (63.9% at 150 µA cm−2), long‐term cycling stability (85% after 3000 cycles), and mechanical flexibility under different bending angles. This work provides key insights into the design and synthesis of 2D c‐MOF films for flexible transparent energy‐storage devices.

Fabrication and assessment of an electrochromic and radar-absorbent dual device based on the new smart polythiophene-based/RGO/Fe3O4 ternary nanocomposite

Both polymeric electrochromic and radar absorption materials have been considered as science hotspots over the past few decades. However, integrating both properties (electrochromic and radar absorption) in a single device has not been addressed to fabricate a multifunctional device so far. Thus, here, we endeavor to shed light on this uncharted area by presenting a new smart ternary nanocomposite (polythiophene-based/RGO-Fe3O4) which can provide both electrochromic and microwave absorbent features simultaneously. In this regard, we synthesized the binary Fe3O4-RGO nanocomposites with different contents of Fe3O4 nanoparticles. Then, this binary nanocomposite is utilized in combination with a polythiophene-based conductive polymer as a tricolor (RGB) organic electrochromic material to synthesize the smart ternary nanocomposite through both in-situ polymerization and physical mixing methods. The ternary nanocomposites containing different weight fractions of Fe3O4-RGO nanoparticles were used to assemble the rigid and flexible ECD devices using flat and fiber substrates such as glass-indium tin oxide (glass-ITO), polyethylene terephthalate-indium tin oxide (PET-ITO) and stainless steel wire (SSW). By applying a voltage of −2.1 to 2.1 v, a reversible color-switching ability was observed between green color (oxidized state), and red color (reduced state) for all ECDs. The average switching time and color memory for the SSW cell were determined to be about 3 s and 155 min, and for both glass-ITO and PET-ITO cells to be 2 s and 210 min, respectively. Additionally, the microwave absorption properties of the prepared ternary nanocomposites were characterized by measuring the electromagnetic parameters such as permittivity, permeability, and reflection loss. A ternary nanocomposite with 3 mm thickness filled with 50 wt% Fe3O4-RGO exhibited a maximum reflection loss as high as −30.2 dB (92% absorption) at 12.3 GHz (in the range of x-bond) with 1.1 GHz bandwidth.

A flexible highly sensitive capacitive pressure sensor

Flexible pressure sensor has been increasingly recognized over the past several decades, but there is still a challenge to fabricate it with a superb sensitivity and large sensing range. Herein, a highly flexible, sensitive and capacitive pressure sensor based on a porous ionic membrane is developed. The innovative sensor contains a polyvinyl alcohol/potassium hydroxide (PVA/KOH) porous ionic dielectric layer and two indium tin oxide polyethylene terephthalate (ITO-PET) films, which are coated on the top and bottom of the dielectric layer, respectively. The sensing mechanism of the sensor is based on the electric double layer capacitors between ITO-PET electrodes and PVA/KOH membrane. By improving the deformability of such elastomer dielectric layer with micro-pores, the sensitivity is greatly enhanced and the detectable range of pressure is significantly widened. Comparing to traditional pressure sensor, the developed sensor provides a high sensitivity up to 20.83/kPa and rapid dynamic responses (50 ms) for pressure measurement. More importantly, the sensor is insensitive to the bending deformation and stable in a low temperature range. Furthermore, a capacitive sensor network is fabricated to measure the spatial pressure distribution and magnitude.

Facile fabrication of W18O49/PEDOT:PSS/ITO-PET flexible electrochromic films by atomizing spray deposition

Electrochromic smart devices with tunable optical properties are on the verge of replacing the conventional windows and curtains. The preparation and commercialization of electrochromic materials are majorly based on vapor phase deposition which is limited by high price and difficult production processes. Here, atomizing spray deposition process is developed for the production of large area, low-cost electrochromic film. W18O49, a promising inorganic EC material, was used to prepare EC film on indium tin oxide-polyethylene terephthalate (ITO-PET) flexible substrate. Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) was also printed on ITO-PET substrate to improve the conductivity of substrate and the adhesion between W18O49 and substrate. The experimental results showed that the transmittance modulation (ΔT) of W18O49/PEDOT:PSS/ITO-PET flexible EC film was 63.34% corresponding to a wavelength of 633 nm. The coloring and bleaching response times of W18O49/PEDOT:PSS/ITO-PET EC film were 18.7 s and 23.2 s, respectively. Furthermore, the as-prepared flexible EC film by atomizing spray deposition method had excellent cyclic stability, and the optical transmittance of the film still retains a high value (70%) after continuous coloring and bleaching for 6000 s.

Multilayer Flexible Pressure Sensor With High Sensitivity Over Wide Linearity Detection Range (August 2021)

Flexible pressure sensors have attracted significant attention in both academic and industrial fields. However, how to design and fabricate a flexible pressure sensor having high sensitivity and good linearity in a wide detection range is still a challenge. To address this challenge, this article proposes a flexible piezoresistive pressure sensor with a multilayer structure consisting of microstructured composite layers (MCLs), which are sandwiched by indium tin oxide-polyethylene terephthalate electrodes and encapsulated by an ultrasoft elastomer frame. The preparation of the conductive composite and the fabrication procedure of the pressure sensor are presented. Due to the point-to-point hemisphere microstructures of the multilayer composite layers, the pressure sensor can perceive pressure with a sensitivity of 7.66 kPa <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> in a range of 0–583 kPa. Besides, the proposed sensor features good linearity of 5.86% and an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R^{2}$ </tex-math></inline-formula> of 0.99. The developed pressure sensor has excellent repeatability of 500 cycles and a fast response time of 80 ms. The proposed sensor is verified by the experiments with primary applications, and the obtained results indicate it could be potentially utilized as wearable detectors.

Terahertz broadband metamaterial absorber enabled by $$\hbox {SiO}_{{{2}}}$$, polyimide and PET dielectric substrates

A broadband polarisation-insensitive terahertz (THz) metamaterial absorber (MMA) is presented in this paper. The MMA consists of a simple planar structure as a unit cell and an optically transparent indium tin oxide (ITO) ground plane, both are separated by a $$50\, \mu \hbox {m}$$ dielectric substrate. We designed three combinations of MMA here, which are ITO–polyimide–ITO, ITO–polyethylene terephthalate (PET)–ITO and ITO–silicon dioxide ( $$\hbox {SiO}_{\mathrm {2}})$$ –ITO for the same planar structure. By changing the substrate of the structure, the resonant frequency and bandwidth of the absorber structure can be varied. The numerical simulation of the absorber shows that the absorptivity is $${>}96{\%}$$ for all three substrates. Polyimide, PET and $$\hbox {SiO}_{\mathrm {2}}$$ based absorbers demonstrated the bandwidth of 0.558 THz, 0.603 THz and 0.658 THz with covered broadband frequency range of 0.4254–0.9829 THz, 0.457–1.16 THz and 0.511–1.169 THz respectively. ITO–PET–ITO absorber structure produced optical transparency. These bandwidths are compatible and convenient for electronic sources in the terahertz region. This study also provides applications in THz sensing and imaging, communication and detection systems.

Terahertz dual-band/broadband metamaterial absorber enabled by SiO2: polyimide and PET dielectric substrates with absorption characteristics

A compact dual-band/broadband polarization in-sensitive terahertz (THz) metamaterial absorber (MMA) is discussed in this article. It consists of a simple planar structure as a unit cell and an optically transparent indium tin oxide (ITO) ground plane, which are separated by a 50 µm dielectric substrate. We designed three combinations of MMA, which are ITO–SiO2–ITO, ITO–polyimide–ITO and ITO–polyethylene terephthalate (PET)–ITO for the same planar structure. The proposed structure has dual-band absorbance with peak absorptivity of >98% for all three given combinations. By changing the substrate of the structure, the resonant frequency and bandwidth of the absorber structure is varied and by adjusting the design parameters, broadband absorbance is achieved for the same planar structure. The numerical simulation of the absorber shows that the broadband absorptivity is >98% for all three substrates. Polyimide, PET and SiO2 based absorbers are demonstrated with bandwidth of 0.467, 0.527 and 0.6 THz with covered broadband frequency range of 0.390–0.857, 0.407–0.934 and 0.433–1.03 THz, respectively. ITO–PET–ITO absorber structures also possess optical transparency. These bandwidths are convenient and compatible with electronic and magnetic sources in the terahertz region. This study provides applications in THz detection, sensing, bolometric imaging, and stealth and communication systems. All three absorbers have greater absorbance characteristics for transverse electric and transverse magnetic polarizations. The proposed structure is working well for wide angles of incident and polarization angles wave up to 90°.

Room‐Temperature‐Processed Fullerene/TiO2 Nanocomposite Electron Transporting Layer for High‐Efficiency Rigid and Flexible Planar Perovskite Solar Cells

Room‐temperature‐processed TiO2 (R‐Lt‐TiO2) electron transporting layers (ETLs) possess low conductivity and connectivity, resulting in poor photovoltaic performance. Herein, an ethanol (EtOH)‐soluble, highly conducting fullerene derivative, C60RT6, was used as an additive for Lt‐TiO2 ETLs. Room‐temperature processed nanocomposite ETL (R‐Fu/Lt‐TiO2) is prepared simply by spin coating a C60RT6 and G‐TiO2 NPs (TiO2 nanoparticle prepared by grinding the bulk TiO2 powder) mixture. R‐Fu/Lt‐TiO2 has better aligned with the frontier orbitals of the FAxMA1−xPbI3, better continuity, conductivity, flatness, and higher surface hydrophilicity compared to Lt‐TiO2 ETL. Perovskite films spin coated on R‐Fu/Lt‐TiO2 ETLs also have slightly larger grains and thickness compared to those deposited on Lt‐TiO2. Perovskite solar cells (PSCs) based on a R‐Fu/Lt‐TiO2 ETL possess higher power conversion efficiency (PCE, up to 20% on glass substrate), less (negligible) current hysteresis, and better long‐term stability compared to those using R‐Lt‐TiO2 as an ETL. The flexible PSC (used indium tin oxide/polyethylene terephthalate (ITO/PET) as a substrate) with a R‐Fu/Lt‐TiO2 ETL achieves a PCE of 18.06% and retains 90% of the initial PCE after 500 bending cycles with a bending radius of 6 mm. The PCE of the flexible cell with a Lt‐TiO2 ETL is only 8.2%, and loses 60% of the initial value after 500 bending cycles.

A Flexible Touch-Sensing Sensor Based on the Theory of Non-Uniform Gradient Potential Distribution

Tactile perception is very important for the physical interaction between robots and the external environments. Based on the theory of non-uniform gradient potential distribution (GPD), a novel non-array flexible touch-sensing sensor is proposed in this paper. It can detect whether there is a touch, and further to know where the touch took place. The sensor uses an indium-tin oxide polyethylene terephthalate (ITO-PET) film as signal generation layer. The electric fields in two different directions are constructed by time-sharing in the ITO-PET conductive plane, and the potential distribution over the ITO-PET film has the characteristics of uniqueness and determinacy. The touching position can be worked out by detecting the potentials of the touching point in two directions, respectively. In order to establish the relation between the position and the potential value effectively, quickly and accurately, the radical basis function (RBF) neural network is used to construct the electric field model and calculate the touching position coordinate. A detection circuit was designed to detect the touching position of the sensor sample. The simulation and experimental results show that the detection principle proposed in this paper is feasible, and the real-time detection of single point touching position can be realized. The touch-sensing sensor is simple in structure, thin in thickness and soft in flexibility. It can cover the surface of the robot and obtain external touching information in real time.

Photoelectrochemical Immunosensor Based on ZnIn2S4/Bi2Se3 Nanocomposite for the Determination of Cardiac Troponin I

In this work, a novel flexible photoelectrochemical immunosensor is developed to determine cardiac troponin I (cTnI) in serum. The flower-like ZnIn2S4 nanospheres (ZIS), as signal amplification material, were successfully synthesized by a solvothermal method. The ZIS and Bi2Se3 were modified on the indium tin oxide- polyethylene terephthalate (ITO-PET) electrode, which effectively accelerates the electronic transition and improved the photocurrent conversion efficiency (signal on). However, the binding of antigen–antibody proteins blocks the electron transfer, resulting in a greatly reduced photocurrent (signal off). By adding the second antibody modified by CdSe quantum dots (CdSe QDs-Ab2), the photocurrent is increased (signal on). The constructed immunosensor has a linear range from 0.08 to 40 ng/mL with a detection limit of 0.026 ng/mL, which shows excellent selectivity, high sensitivity, and good stability. The photoelectrochemical immunosensor has broad application prospects for the clinical examination of myocardial infarction.

Ultra-sensitive detection of parathyroid hormone in human serum: a cheap and practical biosensing platform modified by an epoxy ended-silane agent

ABSTRACTIn this study, we designed an impedimetric immunosensor by modification of disposable ITO-PET (indium tin oxide-polyethylene terephthalate) electrode surface with 3-glycidoxypropyltriethoxysilane (3-GOPE). 3-GOPE silanization agent generates a suitable platform on the ITO-PET working electrode surface for antibody immobilisation and allows a wide determination range for analyte concentrations with the fabricated biosensor. All immobilisation processes, investigation of optimum parameters and characterisation studies of the developed immunosensor were evaluated and followed by Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltammetry (CV). Furthermore, the interactions between anti-parathyroid hormone (anti-PTH) and Parathyroid hormone (PTH) were simultaneously analysed with the Single Frequency Impedance (SFI) technique. All parameters which affect the biosensor response were optimised. A great wide concentration range (1 fg mL−1-2500 fg mL−1) and ultra-low detection limit (0.89 fg mL−1) were obtained under optimum conditions. Moreover, the impedimetric biosensor allowed high sensitivity in the detection of PTH in human serum. It was proved that the fabricated biosensor system has some advantages such as long-term storage life, very low limit of detection, ability to detect the PTH concentrations at femtogram level (1 fg mL−1- 2500 fg mL−1), excellent reproducibility and repeatability, reusability and ultra-high sensitivity.

A Rapid Response/Recovery Ribbon‐like Hydroxyapatite Humidity Sensor with Loose Spatial Structure

AbstractA rapid response/recovery ribbon‐like hydroxyapatite (HAp) humidity sensor with loose spatial structure has been fabricated in this work. The HAp film was prepared on polyethylene terephthalate‐indium tin oxide (PET‐ITO) interdigital substrate by electrochemical deposition method. The HAp film was characterized by XRD, SEM, FTIR techniques. Electrochemically deposited HAp has a preferred orientation in a‐plane, which exposes a great many of hydroxyl groups. The HAp has a flat ribbon‐like microstructure that effectively captures and detects water molecules. The gap of the interdigital electrode was filled with long ribbon‐like HAp to form a loose spatial structure which facilitates water molecules adsorption and desorption. The HAp humidity sensor showed high sensitivity, low hysteresis and good linearity. In particular, HAp sensor has a short response time of 0.9 s and recovery time of 5.6 s. Besides, the humidity sensing mechanism of HAp sensor was also investigated in detail.

A label-free and sensitive impedimetric immunosensor for TNF α biomarker detection based on epoxysilane-modified disposable ITO-PET electrode

ABSTRACTThe present study constructed a simple and cost-effective electrochemical immunosensor based on 3-glycidoxypropyltriethoxysilane (GPTES) monolayer coated indium tin oxide-polyethylene terephthalate (ITO-PET) electrode for selective and sensitive determination of Tumour necrosis factor α (TNF α) cancer biomarker. GPTES was a well-known surface coupling silane agent which had epoxy groups to bind antibodies. Anti-TNF α antibodies were chosen as biorecognition elements and they attached covalently on the GPTES modified ITO-PET electrode. Electrochemical determination of immunoreaction between anti-TNF α antibodies and TNF α antigens was the basic principle of the proposed immunosensor. The electrochemical characterisation of the designed biosensor was tested with electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques. In addition, the surface morphological characteristics of the ITO-PET electrodes after several modification stages were monitored by scanning electron microscopy (SEM) and atomic force microscopy (AFM) imaging. The analytical success of the proposed immunosensor was tested with respect to linear detection range, detection limit, repeatability, reproducibility, reusability, regeneration and long-term stability. The present biosensor had a wide linear range from 0.01 to 1.5 pg/mL and a low detection limit of 3.1 fg/mL. Finally, the biosensor successfully detected TNF α cancer biomarker in human serum samples with high recovery ranges.

An ultrasensitive immunosensor based on tri-armed star poly(glycidyl methacrylate) polymer-coated ITO-PET electrode for detection of neuron-specific enolase in human serum

ABSTRACTIn the present study, an ultrasensitive and simple impedimetric biosensor was fabricated for the determination of neuron-specific enolase (NSE) cancer biomarker. Anti-NSE antibody was covalently immobilised on the indium tin oxide-polyethylene terephthalate (ITO-PET) electrode surface coated with polymer Str(PGMA)3. The star poly(glycidyl methacrylate) polymer Str(PGMA)3 had epoxy side groups and these epoxy groups provided a lot of immobilisation points for antibodies. The process of immunosensor fabrication and successful immobilisation of the antibodies and antigens on the ITO-PET electrode was followed by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques. In addition, EIS technique was utilised for the NSE antigen quantification under optimal experimental conditions. NSE concentration was determined in the range from 0.03 pg/mL to 6 pg/mL with an ultralow detection limit of 9.1 fg/mL. Moreover, the surface topology of the modified surfaces was characterised by scanning electron microscopy (SEM) and atomic force microscopy (AFM) imaging. A low detection limit, a good reproducibility, an excellent storage stability and a good selectivity were obtained. This designed biosensor was employed for the determination of NSE antigen level in human serum samples. The obtained results illustrated that this modification procedure could be applied to determine other biomarkers in human serum samples.

A novel electrochemical immunosensor based on disposable ITO-PET electrodes for sensitive detection of PAK 2 antigen

In the present work, we have developed a novel electrochemical immunosensor based on modified disposable ITO-PET (indium tin oxide - polyethylene terephthalate) electrodes for PAK-2 (p21-activated kinase 2) early detection. An ITO-PET electrode surface was modified with 3-cyanopropyl trimethoxysilane (3-CPTMS), which formed self-assembled monolayers (SAMs). PAK2 immunosensing was performed by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) techniques, square wave voltammetry (SWV) and a single frequency impedance (SFI) technique utilized for specific interaction between the anti-PAK2 and PAK2 antigen. Further, the morphological characterization of each ITO electrode surface was observed by scanning electron microscopy (SEM). All parameters such as 3-CPTMS concentration, antibody concentration and antibody incubation time were optimized. Analytical characteristics of the proposed immunosensor such as linear determination range, repeatability, reproducibility, regeneration, storage life and surface coverage of immunosensors were determined. The PAK2 electrochemical immunosensor performed flawlessly with a wide determination range (from 0.05 pg mL−1 to 2.5 pg mL−1) and low limits of detection (0.0252 pg mL−1) and of quantification (0.0842 pg mL−1). The artificial and human serum samples were tested to verify the viability of the proposed immunosensor.

Highly sensitive and cost-effective ITO-based immunosensor system modified by 11-CUTMS: Analysis of SOX2 protein in real human serum.

In this study it is aimed to construct an immunosensor system for detection of Sex-determining region Y-box 2 (SOX2) antigen by using Indium tin oxide- polyethylene terephthalate (ITO-PET) as working electrode. Firstly, ITO-PET electrode surfaces were hydroxylated by using NH4OH/H2O2/H2O and were incubated with 11-cyanoundecyltrimethoxysilane (11-CUTMS), respectively. After silanization process, anti- SOX2 was immobilized on modified ITO-PET electrodes. All immobilization processes were examined with Electrochemical impedance spectroscopy (EIS) and Cyclic voltammetry (CV). The basic parameters such as 11-CUTMS and anti-SOX2 concentrations, anti-SOX2 and SOX2 incubation period were optimized. The immunosensor prepared under optimal conditions gave a response for a wide concentration range of SOX2 protein (0.02 pg mL-1-2 pg mL-1) and the limit of detection was determined as low as 0.013 pg mL-1. And also, the immunosensor had good repeatability, reproducibility, reusability and long shelf life. Scanning Electron Microscope (SEM) method was utilized to observe the morphologies of the electrode surfaces belonging to all steps. Lastly, seven different real human serum were analyzed with the constructed immunosensor and Enzyme-Linked ImmunoSorbent Assay (ELISA). The results found with these methods were analogised with each other.

Electrospun Ionic Nanofiber Membrane-Based Fast and Highly Sensitive Capacitive Pressure Sensor

Flexible pressure sensor has been widely used in different industries, but there are still some challenges for the fabrication of sensor with a superb sensitivity and large sensing range. In this paper, a flexible capacitive pressure sensor based on electrospun ionic nanofiber membrane is developed. The sensor contains an ionic nanofiber dielectric layer and two indium tin oxide polyethylene terephthalate (ITO-PET) films coated on the top and bottom of the dielectric layer, respectively. The electrical double capacitors are formed at the interface between the ionic nanofiber membrane and the electrodes. When external pressure is applied on the sensor, the distance between two electrodes decreases, which causes the increase of the ionization degree of ionic liquid as well as the effective contact area between the two electrodes and ionic nanofiber dielectric layer. Above changes lead to a rapid increase of the capacitance of the sensor. The sensing principles and the theoretical models of the sensor are systematically studied. Comparing to traditional capacitive pressure sensors, the developed sensor provides a high sensitivity up to 78.54 nF/kPa and a rapid dynamic response (16 ms) for pressure measurement. Experiments are also conducted to investigate the influence of the thickness and the bending radius of ionic nanofiber membrane as well as temperature and humidity of the environment.

Low-Cost and Flexible Anti-Reflection Films Constructed From Nano Multi-Layers of TiO2 and SiO2 for Perovskite Solar Cells

We theoretically investigate the anti-reflection (AR) films based on nano multi-layers (NML) of TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> . This kind of NML dielectric structures have the advantages of low-cost and flexible. Six kinds of transparent conductive substrate (TCS) have been studied here, which are ITO (indium tin oxide) glass, FTO (fluorine-doped tin oxide) glass, ITO PEN (polyethylene naphthalate), FTO PEN, ITO PET (polyethylene terephthalate), and FTO PET, respectively. The AR effect is about 2.3825% for FTO glass substrate, about 3.4232% for ITO glass substrate, about 5.2703% for FTO PEN substrate, about 5.0914% for ITO PEN, about 3.8584% for FTO PET, and about 4.2371% for ITO PET. In practice, this kind of AR films can be widely applicable to enhance the external quantum efficiency (EQE) of the solar cells, and then improve the power conversion efficiency (PCE). Finally, the improved PCE of perovskite solar cells based on our NML AR films is theoretically obtained.