ITO Electrode Research Articles

The Fabrication of a Probe-Integrated Electrochemiluminescence Aptasensor Based on Double-Layered Nanochannel Array with Opposite Charges for the Sensitive Determination of C-Reactive Protein

The effective and sensitive detection of the important biomarker, C-reactive protein (CRP), is of great significance in clinical diagnosis. The development of a convenient and highly sensitive electrochemiluminescence (ECL) aptasensor with an immobilized emitter probe is highly desirable. In this work, a probe-integrated ECL aptamer sensor was constructed based on a bipolar silica nanochannel film (bp-SNF) modified electrode for the highly sensitive ECL detection of CRP. The bp-SNF, modified on an ITO electrode, consisted of a dual-layered SNF film, including the negatively charged inner SNF (n-SNF) and the outer SNF with a positive charge and amino groups (p-SNF). The ECL emitter, tris(bipyridine) ruthenium (II) (Ru(bpy)32+), was stably immobilized in a nanochannel of bp-SNF using the dual electrostatic interactions with n-SNF attracting and p-SNF repelling. The amino groups on the outer surface of bp-SNF were aldehyde derivatized, allowing for the covalent immobilization of recognitive aptamers (5′-NH2-CGAAGGGGATTCGAGGGGTGATTGCGTGCTCCATTTGGTG-3′), leading to the recognition interface. When CRP bound to the aptamer on the recognition interface, the formed complex increased the interface resistance and reduced the diffusion of the co-reactant tripropylamine (TPA) into the nanochannels, leading to a decrease in the ECL signal. Based on this mechanism, the constructed aptamer sensor could achieve a sensitive ECL detection of CRP ranging from 0.01 to 1000 ng/mL, with a detection limit (DL) of 8.5 pg/mL. The method for constructing this probe-integrated ECL aptamer sensor is simple, and it offers a high probe stability, good selectivity, and high sensitivity.

Buried-Metal-Grid Electrodes for Efficient Parallel-Connected Perovskite Solar Cells.

The limited conductivity of existing transparent conducting oxide (TCO) greatly restricts the further performance improvement of perovskite solar cells (PSCs), especially for large-area devices. Herein, buried-metal-grid tin-doped indium oxide (BMG ITO) electrodes are developed to minimize the power loss caused by the undesirable high sheet resistance of TCOs. By burying 140-nm-thick metal grids into ITO using a photolithography technique, the sheet resistance of ITO is reduced from 15.0 to 2.7 Ω sq-1 . The metal step of BMG over ITO has a huge impact on the charge carrier transport in PSCs. The PSCs using BMG ITO with a low metal step deliver power conversion efficiencies (PCEs) significantly better than that of their counterparts with higher metal steps. Moreover, compared with the pristine ITO-based PSCs, the BMG ITO-based PSCs show a smaller PCE decrease when scaling up the active area of devices. The parallel-connected large-area PSCs with an active area of 102.8 mm2 reach a PCE of 22.5%. The BMG ITO electrodes are also compatible with the fabrication of inverted-structure PSCs and organic solar cells. The work demonstrates the great efficacy of improving the conductivity of TCO by BMG and opens up a promising avenue for constructing highly efficient large-area PSCs.

High Stability of Broadband Photomultiplier Organic Photodetector with metal ion-chelated polymer as an electron tunneling injection dipole layer

Broadband photomultiplier organic photodetectors (PM-OPDs) have tremendous potential for use in a variety of photoimaging, physical health monitoring, and wearable applications. However, the interfacial mismatch between electrodes and organic semiconductors inhibits the long-term working stability and reliability of devices. Here, we devised high-performance and stability PM-OPDs by using Zn2+-chelated ethoxylated-polyethylenimine (denoted as PEIE-Zn) as an electron tunneling injection dipole layer between ITO and P3HT:PC71BM: Y6 (3:20:80) broadband photoactive layer. The specific detectivity of the PEIE-Zn-modified PM-OPDs was higher than 1012 Jones in the whole spectral response range (350–1000 nm) under 10V bias. The external quantum efficiency of the device exceeded 1000 % in the whole spectral response range under −20V bias. The transient photoresponse curve of the device has no obvious peaks and fluctuations, and the photocurrent density drops only 2.34 % and 0.25 % at 10 V and −20 V bias after illumination, respectively. The device exhibited very good stability over the course of a week, with its photocurrent density maintained at more than 98.94 % of the initial photocurrent density in the ambient environment without encapsulation. This work improves interface contact by modifying the ITO electrode with PEIE-Zn, providing a practical design solution for devices with high response and stability for broadband PM-OPDs.

Rational design an oval heterostructure and tight linking interface of ZnS@CdS(3) for sensitively photoelectrochemical bioanalysis of PSA

Photoactive material with heterostructures could be effectively employed to promote the photoelectrochemical (PEC) property. Herein, two species heterostructured ZnS@CdS(1−2) composites derived from ZIF-8-S MOFs via a sulfofication reaction in situ using Cd(NO3)2, CdC12 cadmium reagents, and further gained the oval ZnS@CdS(3) after annealing the ZnS@CdS(2). Under irradiation, the PEC results showed that the photocurrent response of ZnS@CdS(3) signally enhanced compared to disordered heterostructures of ZnS@CdS(1), ZnS@CdS(2) and pure ZnS or CdS. It was ascribed to the staggered levels based on matching band-gap to form type II heterojunction of ZnS@CdS(3) could facilitate photo-induced electron/hole (e-/h+) separation and transfer. The obtained photoelectric material with a tight connecting interface also could reduce the carriers transport distance. Besides, the structured and well-distributed ZnS@CdS(3) was beneficial to improve synergistic effect on every component, which resulting in violently photocurrent output. This ZnS@CdS(3) modified ITO electrode to create the PEC biosensor (BSA/anti-PSA/ZnS@CdS(3)/ITO) had been successfully applied for the PSA detection with a wide linear range of 0.001 ∼ 150 ng mL−1 and ultralow detection limit of 0.27 pg mL−1. This research innovatively designed a close contact heterojunction interface with superior PEC nature for biosensor preparations.

Fabrication of Nano- and Micro-Structured PPy Electrode and its Application to Electroporation to Cell

Electroporation using microstructured electrodes, which generate a localized high electric field, allows molecules (genes) to be introduced into cells; however, there are some technical issues with the fabrication process and material in terms of cytotoxicity and cost. In this study, polypyrrole (PPy), a biocompatible and conductive polymer, is nano- and micro-structured for an electrode of electroporation by electrochemical polymerization. Nano- and micro-scale dots of PPy are generated by a specific pulse waveform of applied voltage in a considerably low concentration of pyrrole (monomer) solution. The conductivity of PPy is changed from 4 to 16 S/cm by dopant concentration with a range of 0.025 M to 0.2 M. It is demonstrated that electroporation using the PPy and ITO electrodes introduce test agent of molecules (Propidium Iodide) into HeLa cells, where 10 and 50 V of pulse voltage is applied. The electroporation using nano-scale dots of PPy electrodes provides a 40% higher introduction rate than that of the micro-dots of PPy electrodes. The introduction rate in electroporation using the nano-scale dots of PPy can be maintained above 95% regardless of the application time of voltage, whereas that of the micro-scale dots of PPy electrodes increases with the application time. It is reasonable to assume that the nano- and micro-structured PPy electrodes are effective in electroporation, as the introduction rates on these PPy electrodes are higher than that of the ITO electrode. However, the cell viability in the electroporation using the nano-scale of PPy electrodes decreases by approximately 30% with application time. Both the introduction rate and cell viability slightly decrease with the conductivity of the PPy electrode; therefore, they are dominated by surface morphologies of the PPy electrode and applied voltage as compared to that of electrode conductivity. Nevertheless, it is demonstrated that the nano- and micro-structured PPy electrodes improve the efficiency of electroporation owing to the locally concentrated electric field.

Improvement of Performance of Cu2ZnSn(S, Se)4 Solar Cells by Low‐Temperature Annealing of B‐Doped CdS

It is known that high carrier recombination at the p–n junction interface and low carrier separation ability (CSA) are two main problems resulting in low power conversion efficiency (PCE) of the Cu2ZnSn(S,Se)4 (CZTSSe) solar cell. To resolve these problems, one CZTSSe solar cell is prepared through substituting B‐doped CdS for CdS in a solar cell with the conventional structure of Ag/ITO/ZnO/CdS/CZTSSe/Mo/SLG and annealing B‐doped CdS/CZTSSe/Mo/SLG prior to deposition of ZnO, ITO, and Ag electrode. By optimizing the B doping content in the CdS and annealing temperature and time of the B‐doped CdS/CZTSSe, lattice mismatch between CdS and CZTSSe is decreased and width of depletion region is increased, leading to reduction in interfacial recombination, enhancement in CSA and intensity of incident light passing through the B‐doped CdS, and so increase in PCE from 7.89% of CZTSSe solar cell using CdS as buffer layer to 10.62%. A mechanism of the increment of the PCE induced by B doping and annealing is suggested. This work proposes a method of increasing PCE of CZTSSe solar cell and advances a deeper understanding of the mechanisms behind various parameters in CZTSSe solar cells through theoretical analysis and calculations.

Crystallization Regulation and Defect Passivation of High‐Performance Flexible Perovskite Light‐Emitting Diodes Based on Novel Dielectric/Metal/Dielectric Transparent Electrodes

AbstractPerovskite materials are considered as potential materials suitable for flexible wearable displays due to their excellent optoelectronic properties and flexibility. However, the brittleness of conventional ITO electrodes, as well as the poor crystallization of perovskite on flexible substrates, have hindered the development in flexible perovskite light‐emitting diodes (PeLEDs). Herein, a flexible PeLED based on a novel transparent electrode WO3/Au/WO3 (WAW), combined with the adjustment method of incorporation of polymer [polyethylene oxide‐polypropylene oxide‐polyethylene oxide triblock copolymer (P123)], is proposed to assist crystallization and defect passivation. The strong anchoring effect between P123 and perovskite accelerates the nucleation and crystallization process of perovskite films based on flexible substrates (shortened from 10 min to 1 min), induces the formation of uniform and small‐sized perovskite grains, and passivates non‐radiation defects caused by poor crystal quality. As a result, a high‐performance green PeLED with a maximum external quantum efficiency (EQE) of 14.45% is obtained. The corresponding flexible PeLED displays a maximum EQE of 11.9%, and it can keep a 96.5% original current efficiency after bending for 1000 cycles. This work will provide feasible guidance for the design and manufacture of high‐performance flexible all‐inorganic PeLEDs.

A spatial-potential-resolved electrochemiluminescence biosensor for simultaneous detection of BRCA1 and BRCA2 based on a novel self-luminescent metal–organic framework

Conventional potential-resolved electrochemiluminescence (ECL) biosensors often require the participation of multiple co-reactants, which greatly limits their practical application. To solve the problem, a new kind of self-luminescent copper-based metal–organic framework (Cu-MOF) was synthesized for the first time, Cu-MOF can produce superior positive potential ECL without co-reactants. A novel spatial-potential-resolved electrochemiluminescence biosensor based on Cu-MOF and CdTe@CdS quantum dots (QDs) was constructed for simultaneous detection of BRCA1 and BRCA2. To achieve positive and negative potential luminescence at the same time, Cu-MOF and CdTe@CdS QDs were integrated into different locations of ITO electrode to achieve spatial-potential-resolved ECL only using one co-reactant, which had not been previously reported to my knowledge. Cu-MOF was placed in channel a as the signal luminophor, and Au@Ag NPs were used to quench the positive potential ECL of Cu-MOF by resonance energy transfer (RET) for detection of target BRCA1. Similarly, CdTe@CdS QDs as negative potential ECL material were introduced into channel b for detection of BRCA2. This work not only developed a novel self-luminescent ECL material, but also proposed an ingenious sensing strategy for simultaneous detection of multi-target, which has a wide application prospect in the field of biochemical analysis.

Development of a Novel H-Shaped Electrochemical Aptasensor for Detection of Hg2+ Based on Graphene Aerogels-Au Nanoparticles Composite.

Hg2+, a highly toxic heavy metal, poses significant environmental and health risks, necessitating rapid detection methods. In this study, we employed an electrochemical aptasensor for rapid and sensitive detection of Hg2+ based on DNA strands (H2 and H3) immobilized graphene aerogels-Au nanoparticles (GAs-AuNPs) hybrid recognition interface and exonuclease III (Exo III)-mediated cyclic amplification. Firstly, Gas-AuNPs were modified on the surface of the ITO electrode to form a sensing interface to increase DNA loading and accelerate electron transfer. Then, DNA helper was generated with the addition of Hg2+ via Exo III-mediated cycling. Finally, the hairpin structures of H2 and H3 were opened with the DNA helper, and then the methylene blue (MB) functionalized DNA (A1 and A2) combined with the H2 and H3 to form an H-shaped structure. The current response of MB as an electrochemical probe was proportional to the concentration of Hg2+. Under optimal conditions, the aptasensor showed excellent performance for Hg2+, achieving a linear range from 1 fM to 10 nM and a detection limit of 0.16 fM. Furthermore, the aptasensor was used to detect Hg2+ in spiked milk samples, achieving a high recovery rate and demonstrating promising application prospects.

An innovative approach for the synthesis of 4Tris@Porphyrin and anderson polyoxometalate based covalent organic framework to reveal its potential for photocatalytic properties

Herein, a polyhydroxy containing metallo porphyrin linked through amide functional group with Anderson polyoxometalate (POM) was used to form TPMnA-COF. Structure and applications have been unlocked thoroughly by means of FT-IR, UV–visible, 1HNMR, PXRD, SEM and cyclic voltammetric (CV) spectral analysis. The TPMnA-COF was tested as catalyst to explore the photocurrent and photodegradation properties. ITO electrode was fabricated to study optical activity, absorption study and photocurrent generation. The adsorption study of TPMnA-COF has been studied using Langmuir and Freundlich model with calculated Langmuir constants qm, KL, RL and R2 values of about 12.42 mg/g, 0.33 M-1, 0.30 and 0.98 respectively. The 1/n, Kf and R2 values obtained from Freundlich adsorption isotherm were 0.70, 3.16 M-1 and 0.96 respectively. The band gap value evaluated via absorption edge of UV–visible spectra in DMSO solution was 2.75 eV while the band gap value calculated for ultra-thin film was 1.95 eV. The calculated real, imaginary dielectric constants, Urbach edge, refractive index and the electrical conductivity values for ultra-thin film of TPMnA-COF were 518.8, 2.9 × 10−11-8.1 × 10−11, −3.802 meV, 22.8–22.6 and 8.3 × 104−3.4 × 104 S/m), respectively. Responsivity for film was also tested using purple, blue, green, yellow, orange and red colourlights and the observed responsivity for different lower light intensities were 3.05, 2.9, 1.6, 1.55, 1.5 and 1.4 mA/W respectively. Furthermore, photodegradation activity of TPMnA-COF in Methylene-Blue (MB) and Rhodamine B(Rh–B) dyes under 3 W light. The results showed higher photocatalytic efficiency for Rh–B than that for MB with obtained degradation efficiency of 81 % and 60.4 %, respectively after 660 min. The scavengers such as ammonium oxalate (AO, h+), isopropanol (ISOP, •OH), catalase (CAT, H2O2) and superoxide dismutase (SODM, O2−●) were used to find out the effectiveness of each reactive specie to degrade the dyes solution in the mechanism of degradation. It was observed that AO (h+) and ISOP(•OH) were more active species in the photodegradation mechanism than CAT(H2O2) and SODM(O2−●).

Nanoscale Ag2O decorated UiO-66 metal organic framework for simultaneous electrochemical sensing of heavy metals, Cd2+ and Hg2+

Herein, we come up with a new electrochemical sensing strategy for detecting heavy metal ions present in aqueous media using metal organic framework (MOF) electrode decorated with Ag2O nanoparticles (NPs). Post-synthesis modification route was followed to load the Ag2O NPs into zirconium-based MOF UiO-66 host. In the composite, the NPs were believed to act as the electric current enhancer while UiO-66 provided adsorption sites for heavy metal ions. The ITO electrodes were modified with as prepared composite for the electrochemical detection of Hg2+ and Cd2+ independently as well as simultaneously. The detection of heavy metals was performed by the modified electrodes through differential pulse stripping voltammetry (DPSV) which offered excellent selectivity and with sensitivity values up to 551 μA·μM−1·cm−2 for Cd2+ and 341.2 μA·μM−1·cm−2 for Hg2+. The limit of detection (LOD) for the respective cases, were estimated to be 0.008 μM and 0.003 μM. Technical viability of this approach can be further extended to real sample analysis in soil, river basin, waste land and even ground water for simultaneous detection of heavy metal ions as and when desired.

Ultrathin Self-Powered Heavy-Metal-Free Cu-In-Se Quantum Dot Photodetectors for Wearable Health Monitoring.

Mechanically deformable photodetectors (PDs) are key device components for wearable health monitoring systems based on photoplethysmography (PPG). Achieving high detectivity, fast response time, and an ultrathin form factor in the PD is highly needed for next-generation wearable PPG systems. Self-powered operation without a bulky power-supply unit is also beneficial for point-of-care application. Here, we propose ultrathin self-powered PDs using heavy-metal-free Cu-In-Se quantum dots (QDs), which enable high-performance wearable PPG systems. Although the light-absorbing QD layer is extremely thin (∼40 nm), the developed PD exhibits excellent performance (specific detectivity: 2.10 × 1012 Jones, linear dynamic range: 102 dB, and spectral range: 250-1050 nm at zero bias), which is comparable to that of conventional rigid QD-PDs employing thick Pb-chalcogenide QD layers. This is attributed to material and device strategies─materials that include Cu-In-Se QDs, a MoS2-nanosheet-blended poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) hole transport layer, a ZnO nanoparticle electron transport layer, Ag and ITO electrodes, and an ultrathin form factor (∼120 nm except the electrodes) that enable excellent mechanical deformability. These allow the successful application of QD-PDs to a wearable system for real-time PPG monitoring, expanding their potential in the field of mobile bioelectronics.

Microfluidic Device Integrated With PDMS Microchannel and Unmodified ITO Glass Electrodes for Highly Sensitive, Specific, and Point-of-Care Detection of Copper and Mercury.

This work delves upon developing a two-layer plasma-bonded microfluidic device with a microchannel layer and electrodes for electroanalytical detection of heavy metal ions. The three-electrode system was realized on an ITO-glass slide by suitably etching the ITO layer with the help of CO2 laser. The microchannel layer was fabricated using a PDMS soft-lithography method wherein the mold created by maskless lithography. The optimized dimensions opted to develop a microfluidic device with length of 20 mm, width of 0.5 mm and gap of 1 mm. The device, with bare unmodified ITO electrodes, was tested to detect Cu and Hg by a portable potentiostat connected with a smartphone. The analytes were introduced in the microfluidic device with a peristaltic pump at an optimal flow rate of [Formula: see text]/min. The device exhibited sensitive electro-catalytic sensing of both the metals by achieving an oxidation peak at -0.4 V and 0.1 V for Cu and Hg respectively. Furthermore, square wave voltammetry (SWV) approach was used to analyze the scan rate effect and concentration effect. The device also used to simultaneously detect both the analytes. During simultaneous sensing of Hg and Cu, the linear range was observed between [Formula: see text] to [Formula: see text], the limit of detection (LOD) was found to be [Formula: see text] and [Formula: see text] for Cu and Hg respectively. Further, no interference with other co-existing metal ions was found manifesting the specificity of the device to Cu and Hg. Finally, the device was successfully tested with real samples like tap water, lake water, and serum with remarkable recovery percentages. Such portable devices pave way for detecting various heavy metal ions in a point-of-care environment. The developed device can also be used for detection of other heavy metals like cadmium, lead, zinc etc., by modifying the working electrode with the various nanocomposites.

An in-field assembled hierarchical mesoporous electroenzymatic sensor for sensitive and real-time monitoring of nitrite

Electroenzymatic sensors are promising for nitrite detection but their application in real environmental scenarios is restricted due to the challenges in fabrication complexity and storage stability. Herein, we proposed a “drop & go” strategy to allow non-professionals to fabricate the electroenzymatic sensors in-field for monitoring the nitrite in real-time. To achieve this, hierarchical mesoporous ITO (mesoITO) electrode was prepared via a sol-gel process and a nitrite reductase NrfA originated from Shewanella oneidensis MR-1 was immobilized via a simple dropping process. Cyclic voltammetric (CV) analyses confirmed the direct electron transfer between NrfA and mesoITO electrode. After optimizing the enzyme dosage and electrochemical parameters, both CV and amperometric assays for nitrite detection were developed and a linear detection range of 10–130 μM and 1–140 μM nitrite were determined, respectively. Besides, these electroenzymatic sensors exhibited excellent resistance to the common anions in the water and good performance stability under working conditions. With this basis, the fabricated biosensors were applied for continuously monitoring the nitrite in a denitrifying process and the results were well-matched with the colorimetric method reference. More importantly, the presence of bacterial cells created favorable microenvironment for electroenzymatic nitrite reduction, and promoted the detection of trace nitrite in the bioreactor. This work developed a new methodology for fast electroenzymatic biosensor assembling, facilitate sensitive nitrite quantification in the real environment scenario, and may bring new concept for environment contaminants monitoring in real-time.

Co-reactant confined and vertically ordered silica nanochannel regulated electrochemiluminescence for homogeneous detection of miRNA

Electrochemiluminescence (ECL) arises from the collisional annihilation between the electro-excited luminophore and co-reactant. Most ECL-based bioassays require extensive free co-reactants that collide with luminophores randomly. Herein, the N,N-dimethylaniline (DMA) group was electro-grafted on the ITO electrode surface as the bottom co-reactant layer, and the vertically ordered mesoporous silica film (VMSF) was prepared as the upper layer to regulate the accessibility of Ru(bpy)32+. Thus, the dual-layer functionalized VMSF/N-ITO was newly built for the controllable ECL study. Relevant conditions, including the DMA electro-grafting, VMSF thickness, buffer concentration and pH value, were discussed to improve the ECL efficiency. Based on the VMSF/N-ITO platform, a homogeneous ECL bioassay was developed for miRNA-21 detection. The target nucleotide sequence induced the hybridization chain reaction (HCR) of probes H1 and H2 to absorb free Ru(bpy)32+ as much as possible. Residual Ru(bpy)32+ permeated the VMSF nanochannels to collide with the DMA co-reactant in producing an ECL response. There was a linear relationship between ∆ECL intensity and logarithmic concentration of miRNA-21 in the 1 fM ∼ 100 pM range, and the detection limit was 0.25 fM. The developed approach was probes immobilization-free, highly sensitive, and anti-interference, opening a new avenue for ECL-based bioassays.

Determination of phospholipids in soybean oil using a phospholipase-choline oxidase biosensor based on g-C3N4-TiO2 nanocomposite material

In this paper, we constructed a photoelectrochemical biosensor with ITO electrode as the reaction platform, g-C3N4 and TiO2 as the reaction substrate, Nafion solution as the cross-linking agent, dropwise addition of choline oxidase (ChOx) and optimized its preparation and detection conditions, and finally used this photoelectrochemical biosensor for the detection of Phosphatidylcholine (PC) in actual soybean gross oil. The experiments showed that the PC concentration showed a good linear relationship with the photocurrent response value in the range of 0.05–280 mg/L, and the limit of detection was 0.05 mg/L (S/N = 3). Under the optimized conditions, the sensor had the highest photocurrent response value and the best sensitivity for the artificially simulated gross oil; Phosphatidyl ethandamine (PE), Phosphatidic acid (PA) and Phosphatidyl inositol (PI) showed no significant interference for the detection of PC, and the sensor showed high selectivity for PC detection. The results showed that the relative photocurrent value of the sensor remained at a high level during the storage time of about 32 days, which proved that the electrode storage stability was good, and provided a theoretical basis for the establishment of a fast, accurate and low-cost method for the determination of the PC content, which could more accurately reflect the rule of change of PC in the catalytic reaction of soybean oil degumming, and further realise the precise and moderate processing of fats and oils.

Ultra-sensitive photoelectrochemical sensor for copper ion detection based on ITO/BiVO4 photoelectrode

In this work, a photoelectrochemical sensor for Cu2+ trace detection was prepared based on the excellent semiconductor material BiVO4 modified ITO electrode. It was found that Cu2+ formed a doping effect by adsorption on the surface of ITO/BiVO4 electrode, which inhibited the photogenerated electron complex and thus caused an increase in photocurrent. In addition, due to the complexation effect of EDTA on Cu2+, the Cu2+ adsorbed on the electrode surface is desorbed and the photocurrent returns to the blank value, making it possible to reuse electrodes. Under optimal conditions, the linearity range was measured between 0.1 pM and 0.1 μM and the detection limit was 0.063 pM. The PEC sensor exhibits the advantages of high sensitivity and reusability for Cu2+ detection. This provides a novel PEC detection platform for Cu2+ monitoring in environmental water samples.

Toward Semitransparent PIN-type Perovskite Solar Cells with Sputtered ITO Electrode: Architecture and Process Optimizations

Toward Semitransparent PIN-type Perovskite Solar Cells with Sputtered ITO Electrode: Architecture and Process Optimizations

Learning‐Effective Mixed‐Dimensional Halide Perovskite QD Synaptic Array for Self‐Rectifying and Luminous Artificial Neural Networks

AbstractA mixed‐dimensional heterostructure comprising nanomaterials with varying dimensions provides a promising structure for an artificial synapse for reconfigurable neuromorphic functions. In this study, an 8 × 8 memristor crossbar array based on a mixed‐dimensional heterostructure comprising Cs1−xFAxPbBr3 (0.00 ≤ x ≤ 0.15) quantum dots (QDs) and different dimensional interfacial nanomaterial layers between the Al and ITO electrodes is designed and fabricated. This array device exhibits a high yield and reliable self‐rectifying analog switching characteristics with low synaptic‐coupling (SC, up to 5.19 × 10−5) and light emission, facilitating stimuli response visualization and preventing undesired pathways in the network array. Furthermore, because the formamidinium (FA) concentration alters the QD size, thereby engineering interfacial band alignment in the heterostructure, the essential synaptic properties such as dynamic range, SC, and nonlinearity can be improved. Especially, as x increases from 0 to 0.11, the recognition accuracy for the MNIST patterns increases significantly, from 68.97% to 89.08%, even for single‐layer ANNs. The energy consumption required for a specific accuracy level is reduced by a factor of 25.15. The utilization of mixed‐dimensional perovskite QD‐based heterostructures in neural networks may provide desirable neuromorphic electronic functions with enhanced learning capability and energy efficiency, while preventing unwanted neural signals.

Fabrication of transparent flexible electrodes on polyethylene terephthalate substrate with high conductivity, high transmittance, and excellent stability

Transparent flexible electrodes based on silver nanowires (AgNWs) have great potential for practical applications and many studies have been carried out to improve their conductivity, transparency, and surface roughness. In this study, we demonstrate a new approach for the fabrication of high-performance transparent flexible electrodes based on AgNWs and graphene oxide (GO) on polymer substrates using the pressing method. The surface morphology of the pressed AgNW/GO electrode was characterised by atomic force microscopy (AFM) and observed by scanning electron microscope (SEM). The electrode had a low surface roughness with the root mean square (Rq) of 7 nm. The electrode exhibits a low sheet resistance of 22 Ω/sq, a high transmittance of ~88%, resulted in a figures-of-merit (FoM) value of ~12.6. The optical and electrical properties of the electrode are comparable to that of the flexible ITO electrode. In addition, the electrodes also displayed outstanding durability and mechanical stability. This simple and scalable fabrication method is expected to contribute to future studies on flexible transparent conductive electrodes.