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Binary metal sulfides have been explored as sodium storage materials owing to their high theoretical capacity and high stable cyclability. Nevertheless, their relative high charge voltage and relatively low practical capacity make them less attractive as an anode material. To resolve the problem, addition of alloying elements is considerable. Copper antimony sulfide is investigated as a representative case. In this study, we do not only perform electrochemical characterization on CuSbS2, but also investigate its nonequilibrium sodiation pathway employing in-/ex situ transmission electron microscopy, in situ X-ray diffraction, and density functional theory calculations. Our finding provides valuable insights on sodium storage into ternary metal sulfide including an alloying element.

We report an artificial eardrum using an acoustic sensor based on two-dimensional MXene (Ti 3 C 2 T x ), which mimics the function of a human eardrum for realizing voice detection and recognition. Using MXene with a large interlayer distance and micropyramid polydimethylsiloxane arrays can enable a two-stage amplification of pressure and acoustic sensing. The MXene artificial eardrum shows an extremely high sensitivity of 62 kPa −1 and a very low detection limit of 0.1 Pa. Notably, benefiting from the ultrasensitive MXene eardrum, the machine-learning algorithm for real-time voice classification can be realized with high accuracy. The 280 voice signals are successfully classified for seven categories, and a high accuracy of 96.4 and 95% can be achieved by the training dataset and the test dataset, respectively. The current results indicate that the MXene artificial intelligent eardrum shows great potential for applications in wearable acoustical health care devices.

Lithium–sulfur (Li–S) batteries are one of the main challenges facing Li-ion technology because the insulating nature of sulfur and the shuttle phenomenon of dissolved lithium polysulfides (LPSs) i...

Controlling molecular self-assembly of organic semiconductors is a key factor in enhancing the performance of organic electronics and optoelectronics. However, unlike various p-type organic semiconductors, it has proven elusive to control molecular self-assembly with about tens of nm dimensions using n-type organic semiconductors including perylene diimide (PDI), which is the most promising alternative to fullerene derivatives, without using an additional synthetic method or additives, thus far. Here, we developed a simple self-assembling method for the hierarchical self-assembly of PDI crystals with nanometer-to-micrometer scale features using pristine PDI-C8 without using an additional synthetic method or additive. Interestingly, we observed crystalline and optical properties of self-assembled PDI crystals depending on their size and structural features. In addition, we fabricated p-n junctions composed of PDI and poly(3-hexylthiophene) (P3HT), where the p-n junctions had coassembled and blended nanomorphologies, and confirmed that coassembled nanomorphologies enabled more effective energy transfer than the blended nanomorphologies.

Two-dimensional transition metal carbides (MXenes) have attracted much attention due to their excellent electrical conductivity and outstanding performances in energy storage, telecommunication, and sensing applications. It is known that MXene flakes are readily oxidized in either humid air or aqueous environments. While the chemical instability of MXenes may limit their use in applications involving ambient environments and long-term operation, oxidation behaviour of MXene films has not been addressed. In this work, we demonstrate a hydrogen annealing method to increase the oxidation stability of Ti3C2 MXene in two different aspects: (1) dramatic improvement in the oxidation stability of pristine MXene films against harsh conditions (100% relative humidity, 70 °C), and (2) large recovery in the electrical conductivity of previously oxidized Ti3C2 MXene films. We also demonstrate an electric-field-induced heater capable of stable operation under highly oxidizing conditions, based on the oxidation-resistant MXene film. A total loss of heat generation ability was observed for the as-prepared MXene film, while the hydrogen-annealed one maintained its bright infrared radiation, under the highly oxidizing conditions. This work offers a solution to industrial applications of unprotected MXene films, securing their stable and long-term operation in humid conditions.

The development of high performance and cost-effective electrode materials is the main challenge for the commercialization of sodium ion batteries. Here, we suggest a substantial iron-doped sodium vanadium fluorophosphate and sodium vanadium phosphate composite as a promising cathode. Iron substitution enhances ionic diffusivity and lowers the bandgap, and, thus, improves sodium storage performance. The origin of the enhanced performance is investigated employing in situ X-ray diffraction, ex situ X-ray photoelectron spectroscopy, density functional theory calculation, and electrochemical characterization. Moreover, we demonstrate its full cell configuration with earth-abundant element-based copper sulfide anodes. The suggested cathode and sodium ion battery full cell exhibits well-balanced sodium storage performance in terms of energy density, C-rate capability, cycling stability, and low cost. The low cost and high performance of the full cell make it an attractive choice for energy storage systems and high power applications to support lithium ion batteries.

Binary metal sulfides have been explored as sodium storage materials owing to their high theoretical capacity and high stable cyclability. Nevertheless, their relative high charge voltage and relatively low practical capacity make them less attractive as an anode material. To resolve the problem, addition of alloying elements is considerable. Copper antimony sulfide is investigated as a representative case. In this study, we do not only perform electrochemical characterization on CuSbS

Over the past few years, metal nanowire networks have attracted attention as an alternative to transparent conducting oxide materials such as indium tin oxide for transparent conducting electrode applications. Recently, electrodeposition of metal on nanoscale template is widely used for formation of metal network. In the present work, junctionless Cu nanowire networks were simply fabricated on a substrate by forming a nanostructured Ru with 80 nm width as a seed layer, followed by direct electroless deposition of Cu. By controlling the density of Ru nanowires or the electroless deposition time, we readily achieve desired transmittance and sheet resistance values ranging from ∼1 kΩ sq−1 at 99% to 9 Ω sq−1 at 89%. After being transferred to flexible substrates, the nanowire networks exhibited no obvious increase in resistance during 8000 cycles of a bending test to a radius of 2.5 mm. The durability was verified by evaluation of its heating performance. The maximum temperature was greater than 180 °C at 3 V and remained constant after three repeated cycles and for 10 min. Transmission electron microscopy and x-ray diffraction studies revealed that the adhesion between the electrolessly deposited Cu and the seed Ru nanowires strongly influenced the durability of the core–shell structured nanowire-based heaters.

Nanoporous materials have attracted considerable attention for various potential applications in sensors, optical, magnetic and electronic devices due to their high specific surface area and distinctive physicochemical properties. Particularly, porous carbon-composite materials can be used in the field of catalysis, separation, purification, capture and energy storage/conversion systems. In this work, we prepared highly porous carbon-composite nanofibers with hollow-structures by electrospinning combined with hundreds of nanometers sized silica nanoparticles and 2D MXene flakes and demonstrated the applications in ion storage systems. Firstly, nanoparticles and MXene flakes embedded-polyacrylonitrile(PAN) was electrospun with single and dual nozzles, respectively. In the case of electrospinning via dual nozzle , PAN/Mxene solution and polymethyl methacrylate (PMMA) solution were used as shell and core materials, respectively. After the electrospinning process, the nanofibers were stabilized at 280oC, followed by a carbonization at 800oC for 1h. Selective removal of silica nanoparticles by HF solution after the carbonization and the decomposition of PMMA at 400oC resulted in the well defined hollow-structured carbon-composite nanofibers. The morphologies of the nanofibers depends on the concentration and size of silica nanoparticles and Mxene flakes and the each specific surface area was higher about 6 and 7 times than those of normal carbon nanofibers. Particularly, the carbonization of MXene-embedded nanofibers successfully removed the functional groups on the MXene such as –F and –OH which are known to hinder Li-ion transport. The hollow structured carbon composite nanofibers with tailored surface terminations and the increased specific surface area were utilized as a electrode materials of ion storage systems and showed improved electrochemical performance compared to normal carbon nanofibers or carbon-MXene composite paste. Figure 1

With the fast growth of wearable & miniaturized electronic devices, internet of things (IoT), and 5G telecommunications, the need for ultrathin, lightweight, and flexible energy storage devices has expanded significantly. Micro-supercapacitors (MSCs) with electrically isolated interdigitated electrodes, have attracted great interest as major power sources for micro-electronic devices, offering high power efficiency, superior rate capability, and excellent cycle durability. MXenes, two-dimensional (2D) metal carbides and nitrides, have been considered as a promising candidate for state-of-the-art energy storage applications, due to their intriguing combinational properties such as excellent electrical conductivity, large surface area, tunable surface chemistry, and pseudo-capacity. 1 In this work, we report titanium carbides (Ti3C2) MXene-based MSCs with sub-micron gap between electrodes exhibiting high areal capacitance and superior rate capability, realized by microfabrication method based on focused ion beam (FIB) and photolithography.2 We also demonstrate a facile and reliable process for scalable manufacturing of on-chip and flexible MSCs for wearable/portable and miniaturized microelectronics. The MXene MSCs fabricated utilizing the cutting-edge nanofabrication technology in an 8-inch wafer have shown an outstanding volumetric capacitance and stable cyclic performances, suggesting the developed manufacturing process can accelerate commercialization of MXene-based energy storage devices as power sources for next-generation wearable and miniaturized microelectronics.3 [References] 1 Energy Environ. Sci. 9 2847 (2016) 2 Nano Energy 81 (2021), 105616 3 Chem. Eng. J., 450, 138456 (2022)

In this study, we investigated the translocation characteristics of flagellar filaments (Salmonella typhimurium) and flagellin subunits through silicon nitride nanopores in tandem with optical micr...

MXenes have attracted great attention for their potential applications in electrochemical and electronic devices due to their excellent characteristics. Traditional sound sources based on the thermoacoustic effect demonstrated that a conductor needs to have an extremely low heat capacity and high thermal conductivity. Hence, a thin MXene film with a low heat capacity per unit area (HCPUA) and special layered structure is emerging as a promising candidate to build loudspeakers. However, the use of MXenes in a sound source device has not been explored. Herein, we have successfully prepared sound source devices on an anodic aluminum oxide (AAO) and a flexible polyimide (PI) substrates by using the prepared Ti3C2 MXene nanoflakes. Due to the larger interlayer distance of MXene, the MXene-based sound source device has a higher sound pressure level (SPL) than that of graphene of the same thickness. High-quality Ti3C2 MXene nanoflakes were fabricated by selectively etching the Ti3AlC2 powder. The as-fabricated MXene sound source device on an AAO substrate exhibits a higher SPL of 68.2 dB (f = 15 kHz) and has a very stable sound spectrum output with frequency varying from 100 Hz to 20 kHz. A theoretical model has been built to explain the mechanism of the sound source device on an AAO substrate, matching well with the experimental results. Furthermore, the MXene sound source device based on a flexible PI substrate has been attached to the arms, back of the hand, and fingers, indicating an excellent acoustic wearability. Then, the MXene film is packaged successfully into a commercial earphone case and shows an excellent performance at high frequencies, which is very suitable for human audio equipment.

MXenes are a prominent family of two-dimensional materials because of their metallic conductivity and abundant surface functionalities. Although MXenes have been extensively studied as bulk particles or free-standing films, thin and transparent films are needed for optical, optoelectronic, sensing, and other applications. In this study, we demonstrate a facile method to fabricate ultrathin (∼10 nm), Ti3C2Tx MXene films by an interfacial assembly technique. The self-assembling behavior of MXene flakes resulted in films with a high stacking order and strong plane-to-plane adherence, where optimal films of 10 nm thickness displayed a low sheet resistance of 310 Ω/□. By using surface tension, films were transferred onto various types of planar and curved substrates. Moreover, multiple films were consecutively transferred onto substrates from a single batch of solution, showing the efficient use of the material. When the films were utilized as gas sensing channels, a high signal-to-noise ratio, up to 320, was observed, where the gas response of films assembled from small MXene flakes was 10 times larger than that from large flakes. This work provides a facile and efficient method to allow MXenes to be further exploited for thin-film applications.

Gas molecules are known to interact with two-dimensional (2D) materials through surface adsorption where the adsorption-induced charge transfer governs the chemiresistive sensing of various gases. Recently, titanium carbide (Ti

Two-dimensional (2D) transition metal carbides (MXenes) exhibit outstanding performances in many applications, such as energy storage, optoelectronics, and electrocatalysts. However, colloidal solutions of Ti3C2Tx MXene flakes deteriorate rapidly under ambient conditions due to the conversion of the titanium carbide to titanium dioxide. Here, we discuss the dominant factors influencing the rate of oxidation of Ti3C2Tx MXene flakes, and present guidelines for their storage with the aim of maintaining the intrinsic properties of the as-prepared material. The oxidation stability of the Ti3C2Tx flakes is dramatically improved in a system where water molecules and temperature were well-controlled. It was found that aqueous solutions of Ti3C2Tx MXene can be chemically stable for more than 39 weeks when the storage temperature (−80 °C) is sufficiently low to cease the oxidation processes. It was also found that if the Ti3C2Tx flakes are dispersed in ethanol, the degradation process can be significantly delayed even at 5 °C. Moreover, the oxidation stability of the Ti3C2Tx flakes is dramatically improved in both cases, even in the presence of oxygen-containing atmosphere. We demonstrate practical applications of our approach by employing Ti3C2Tx in a gas sensor showing that when oxidation is inhibited, the device can retain the original electrical properties after 5 weeks of storage.

Skin-attachable gas sensors provide a next-generation wearable platform for real-time protection of human health by monitoring environmental and physiological chemicals. However, the creation of skin-like wearable gas sensors, possessing high sensitivity, selectivity, stability, and scalability (4S) simultaneously, has been a big challenge. Here, an ionotronic gas-sensing sticker (IGS) is demonstrated, implemented with free-standing polymer electrolyte (ionic thermoplastic polyurethane, i-TPU) as a sensing channel and inkjet-printed stretchable carbon nanotube electrodes, which enables the IGS to exhibit high sensitivity, selectivity, stability (against mechanical stress, humidity, and temperature), and scalable fabrication, simultaneously. The IGS demonstrates reliable sensing capability against nitrogen dioxide molecules under not only harsh mechanical stress (cyclic bending with the radius of curvature of 1 mm and cyclic straining at 50%), but also environmental conditions (thermal aging from -45 to 125 °C for 1000 cycles and humidity aging for 24 h at 85% relative humidity). Further, through systematic experiments and theoretical calculations, a π-hole receptor mechanism is proposed, which can effectively elucidate the origin of the high sensitivity (up to parts per billion level) and selectivity of the ionotronic sensing system. Consequently, this work provides a guideline for the design of ionotronic materials for the achievement of high-performance and skin-attachable gas-sensor platforms.

The formation of uniform sheets of exfoliated MXene over a large area is important for improving their performance in practical applications. In this study, the Langmuir-Schaefer technique was employed to deposit uniform MXene sheets on a solid substrate and control the morphological structure over a large area. At the liquid-gas interface, MXene flakes were densely compressed into nanosheets with minimal gaps between them at 20 mN/m. Through further compression, the wrinkle morphologies of MXene sheets tend to be perpendicularly aligned to the compression direction. These wrinkle structures were also exhibited when MXene sheets were mixed in equal proportions with graphene oxide sheets. Owing to the close correlation of the morphologies of MXene films with the performance of MXene-based materials, the technique employed in this study can provide a route for applications requiring wrinkled MXene, ranging from nanoelectronic devices to energy storage materials, such as supercapacitors and battery electrodes.

Lithium-sulfur (Li-S) batteries are one of the main challenges facing Li-ion technology because the insulating nature of sulfur and the shuttle phenomenon of dissolved lithium polysulfides (LPSs) in liquid electrolytes result in critical problems, including low Coulombic efficiency, loss of active material, and rapid capacity decay. Here, we oxidized delaminated transition metal carbides (MXenes) using CO

For lithium–sulfur (Li–S) batteries to be used in practical applications, the low conductivity of elemental sulfur and the shuttle phenomenon need to be overcome together with the preparation of cathode material of a high sulfur content. Herein, we report a two-dimensional (2D) delaminated MXene-wrapped sulfur composite (S@d-MXene) synthesized via facile electrostatic self-assembly. The ultrathin and flexible 2D MXene wrapping of sulfur particles provides a pathway for lithium-ion transport and electron transfer while suppressing the shuttle phenomenon. In addition, the gap between sulfur particle and the d -MXene sheets wrapping its surface provides a buffering space for the volume expansion of the sulfur particle. The Li–S battery with a high sulfur content of 83.8% in S@d-MXene composite provides a capacity of ∼506 mAh g−1 after 500 cycles at a current density of 1C, with a Coulombic efficiency of 99% and an extremely low capacity decay rate (0.047% per cycle).

Detection of single nanoparticles or molecules has often relied on fluorescent schemes. However, fluorescence detection approaches limit the range of investigable nanoparticles or molecules. Here, we propose and demonstrate a non-fluorescent nanoscopic trapping and monitoring platform that can trap a single sub-5-nm particle and monitor it with a pair of floating nonlinear point sources. The resonant photon funnelling into an extremely small volume of ~5 × 5 × 7 nm3 through the three-dimensionally tapered 5-nm-gap plasmonic nanoantenna enables the trapping of a 4-nm CdSe/ZnS quantum dot with low intensity of a 1560-nm continuous-wave laser, and the pumping of 1560-nm femtosecond laser pulses creates strong background-free second-harmonic point illumination sources at the two vertices of the nanoantenna. Under the stable trapping conditions, intermittent but intense nonlinear optical spikes are observed on top of the second-harmonic signal plateau, which is identified as the 3.0-Hz Kramers hopping of the quantum dot trapped in the 5-nm gap., Detection of single nanoparticles or molecules often relies on the attachment of fluorescent labels. Here, the authors demonstrate trapping a single nanoparticle on a bowtie nanoantenna and monitoring via second harmonic generation from the particle.

In an effort to help meet the demand for promising renewable sources of energy, research into innovative downstream processing for microalgae biorefineries is actively underway. In the current work, we used octahedrally shaped ZnFe2O4 nanoparticles for both harvesting and disrupting the cells of microalgae. We were able to use ZnFe2O4 octahedrons as magnetic flocculants and cell-disruption agents because ZnFe2O4 nanoparticles have both magnetic and photocatalytic properties. The ZnFe2O4 octahedrons, when simply functionalized with the aminosilane N-[3-(trimethoxysilyl)propyl] ethylenediamine, enabled a rapid and energy-efficient harvesting of microalgae. Furthermore, the ZnFe2O4 octahedrons, well-known for having photocatalytic properties superior to those of ZnFe2O4 nanoparticles with other morphologies, were used to lyse the algal cell wall with the aid of H2O2 under simulated sunlight irradiation. We expect microalgae whose cells can be both magnetophoretically separated and lysed by the same ZnFe2O4 n...

In the present study, silver nanoparticles (AgNPs) with a flower-like structure were synthesized through an easy, rapid and eco-friendly pathway using Phyllanthus amarus leaf extract. The obtained AgNPs were characterized using ultraviolet–visible (UV–Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). In addition, the antimicrobial and catalytic activities of the bio-synthesized AgNPs were carried out. Our results indicated that the concentration of the Ag precursor and the volume of the leaf extract played key roles in the formation of the flower-shaped AgNPs. Morphology study confirms the shape of the obtained bio-AgNPs as flower like structure. This study also showed the presence of clear capping layers surrounding and apparently interacting with the nanoparticles. Moreover, our studies indicated this interaction to involve bio-organic capping agents in the leaf extract. UV–Vis absorption spectra confirmed the formation of AgNPs with an optimized size. The zeta (ζ) potential of the AgNPs attests the stability of the nanoparticles. FTIR spectra provided evidence for the presence of biomolecules responsible for the reduction as well as capping of the AgNPs. Finally, the bio-synthesized AgNPs were shown to be an excellent microbial activity against the selected pathogens and enhanced catalyst of the reduction of rhodamine B.

Solid-state nanopore sensors have been used to measure the size of a nanoparticle by applying a resistive pulse sensing technique. Previously, the size distribution of the population pool could be investigated utilizing data from a single translocation, however, the accuracy of the distribution is limited due to the lack of repeated data. In this study, we characterized polystyrene nanobeads utilizing single particle recapture techniques, which provide a better statistical estimate of the size distribution than that of single sampling techniques. The pulses and translocation times of two different sized nanobeads (80 nm and 125 nm in diameter) were acquired repeatedly as nanobeads were recaptured multiple times using an automated system controlled by custom-built scripts. The drift-diffusion equation was solved to find good estimates for the configuration parameters of the recapture system. The results of the experiment indicated enhancement of measurement precision and accuracy as nanobeads were recaptured multiple times. Reciprocity of the recapture and capacitive effects in solid state nanopores are discussed. Our findings suggest that solid-state nanopores and an automated recapture system can also be applied to soft nanoparticles, such as liposomes, exosomes, or viruses, to analyze their mechanical properties in single-particle resolution. This article is protected by copyright. All rights reserved

A facile way to fabricate the highly uniform and mono-disperse silver nanoparticles (AgNPs) immobilized in polymer nanofibers has been successfully developed by combining electrospinning technique and photo-reduction method, applicable as efficient catalysts. Herein, poly-vinyl pyrrolidone (PVP) forbids the silver grain growth due to its steric effect and polymethacrylic acid (PMAA) contributes abundant carboxylic groups, which enhances the absorption of silver ions in nanofibers ensuring the growth of high density of AgNPs. UV exposure of nanofibers for 24 h leads to the maximum density of growth of AgNPs in PMAA/PVP nanofibers. The present investigation indicates that the size and spatial distribution of AgNPs can be tailored by changing the concentration of AgNO3 solution consequently, controlling the catalytic activity of AgNPs-immobilized nanofibrous mats. Interestingly, the prepared nanofibers exhibit good catalytic activity towards the reduction of methylene blue an environmental organic pollutant, due to the high density of AgNPs formation in nanofibers.

Graphitic carbon fiber felt (GCFF) with a crystalline graphitic carbon structure was facilely prepared by a combination of electrospinning and graphitization (2800 °C heat treatment) and was used as an interlayer between the cathode and separator in Li-S batteries. This GCFF interlayer trapped the polysulfides on the cathode side and increased the utilization of sulfur by suppressing the shuttle phenomenon. Also, the GCFF was shown to be able to act as an upper current collector to reduce the charge-transfer resistance owing to the high crystallinity of the graphitic carbon fibers. The sulfur cathode with the GCFF interlayer showed a high specific initial discharge capacity of 1280.14 mAh g −1 and excellent cycling stability (1004.62 mAh g −1 after 100 cycles) at 0.2 C. Also, an image of the glass fiber (GF) separator on the anode side confirmed the presence of an SEI after 200 cycles, which apparently resulted from stable Li deposition on the Li metal because of the low or medium concentration of sulfur in the electrolyte solution. Our observations should contribute to elucidating the key features of complex three-dimensional carbon fabrics with crystalline graphitic structures that allow them, when inserted as interlayers, to markedly improve the performance of rechargeable batteries.

Well-aligned, high-resolution (10 nm), three-dimensional (3D) hybrid nanostructures consisting of patterned cylinders and Au islands were fabricated on ITO substrates using an ion bombardment process and a tilted deposition process. The fabricated 3D hybrid nanostructure-embedded ITO maintained its excellent electrical and optical properties after applying a surface-structuring process. The solution processable organic photovoltaic device (SP-OPV) employing a 3D hybrid nanostructure-embedded ITO as the anode displayed a 10% enhancement in the photovoltaic performance compared to the photovoltaic device prepared using a flat ITO electrode, due to the improved charge collection (extraction and transport) efficiency as well as light absorbance by the photo-active layer.

We fabricated webs of carbon fibers coated with Ni3S2/Ni particles having three-dimensional snowflake shapes by using electrospinning and electroless-plating methods in order to obtain high-performance cathode materials for lithium batteries. These snowflake shapes, i.e., spheres with urchin-like surfaces, can be expected to yield large surface areas, excellent electrical conductivity and high penetrability of electrolytes into the web structure. A lithium battery cell using the cathode materials we fabricated was indeed found to exhibit good cycling stability and specific capacity (initial discharge capacity of 554.67mAh/g, irreversible capacity of about 50mAh/g) and to retain 65% of its capacity after 30cycles. Therefore, this new fabrication method should help produce rechargeable lithium batteries consisting of three-dimensional electrode materials with many reactive sites and with superior electrolyte penetrability. Display Omitted Web of carbon fibers coated with 3D snowflake-shaped Ni3S2/Ni was synthesized by electroless Ni plating.The Ni3S2/Ni compounds on carbon-fiber webs can use without conductive material and binder.High capacity of 554.67mAh/g was obtained after 30cycles at 100mA/g current density.

MXenes have attracted great attention for their potential applications in electrochemical and electronic devices due to their excellent characteristics. Traditional sound sources based on the thermoacoustic effect demonstrated that a conductor needs to have an extremely low heat capacity and high thermal conductivity. Hence, a thin MXene film with a low heat capacity per unit area (HCPUA) and special layered structure is emerging as a promising candidate to build loudspeakers. However, the use of MXenes in a sound source device has not been explored. Herein, we have successfully prepared sound source devices on an anodic aluminum oxide (AAO) and a flexible polyimide (PI) substrates by using the prepared Ti