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Addressing the loss of substrate conductivity after enduring numerous bending stands as a significant challenge for flexible electronics. The primary cause of reduced electrical conductivity in flexible polymer matrices is disorganization of conducting channels by mechanical stress generated during repeated stretching cycles. In this feature article, we extensively reviewed the strategies adopted to control structure formation of conducting networks by optimizing filler and matrix interactions at length scale. Studies, including our recent experiments, indicate that fractal formation of filler assemblies in polymer matrix determines the stability of conducting channels. A wide range of polymers and conducting fillers with different geometries and functional attributes have been analyzed to highlight the intra and intermolecular reinforcing effects to address the shear stresses originating in flexible substrates. Understanding non-bonded interactions between polymers and fillers may lead to the development of desired formulation of conducting inks to print on flexible surfaces for next-generation wearable electronics. [ABSTRACT FROM AUTHOR]

Niobium oxide thin films were grown on both rigid and flexible substrates using DC magnetron sputtering for electrochromic applications. Three experimental series were conducted, varying the oxygen to argon flow rate ratio and deposition time. In the first series, the oxygen to argon ratio was adjusted from 0 to 0.32 while maintaining a constant growth time of 30 min. For the second and third series, the oxygen to argon ratios were fixed at 0.40 and 0.56, respectively, with deposition times ranging from 15 to 60 min. A structural transition from crystalline to amorphous was observed at an oxygen to argon flow rate ratio of 0.32. This transition coincided with a change in appearance, from non-transparent with metallic-like electrical conductivity to transparent with dielectric behavior. The transparent niobium oxide films exhibited thicknesses between 51 nm and 198 nm, with a compact, dense, and featureless morphology, as evidenced by both top-view and cross-sectional images. Films deposited on flexible indium tin oxide (ITO)-coated polyethylene terephthalate (PET) substrates displayed a maximum surface roughness (Sq) of 9 nm and a maximum optical transmission of 83% in the visible range. The electrochromic response of niobium oxide thin films on ITO-coated PET substrates demonstrated a maximum coloration efficiency of 30 cm2 C−1 and a reversibility of 96%. Mechanical performance was assessed through bending tests. The ITO-coated PET substrate exhibited a critical bending radius of 6.5 mm. Upon the addition of the niobium oxide layer, this decreased to 5 mm. Electrical resistance measurements indicated that the niobium oxide film mitigated rapid mechanical degradation of the underlying ITO electrode beyond the critical bending radius. [ABSTRACT FROM AUTHOR]

In recent years, several efforts have been dedicated to the development of portable and versatile microwave technologies for contact‐less liquid sensing and characterization. With respect to existing electrochemical and optical approaches, microwave liquid sensors enable high‐sensitivity and label‐free sensing with increased operation stability and robustness, and in relatively simple and inexpensive device formats. Nonetheless, current microwave solution sensing systems are still limited by either their reliance on wired connections to external electronics or by their widespread implementation on conventional rigid substrates. These limitations hinder the seamless integration of such sensors within conventional (micro)fluidic systems for real‐time solution monitoring, particularly when near‐field coupling between the sensors and the liquid under test needs to be established for operation. By leveraging the versatile material deposition capabilities granted by solution‐phase processing, a fully printed and mechanically flexible microwave resonator design is introduced that allows untethered solution sensing whether immersed in or in proximity to the liquid under test. The mechanical properties of this device facilitate the noninvasive/nondestructive integration of the device on commercial tubing. These characteristics, along with its cost‐effectiveness and its ease of fabrication, favor the seamless integration of this device into fluidic and microfluidic systems, for real‐life applications. [ABSTRACT FROM AUTHOR]

Surface enhanced Raman scattering (SERS) is a technique that utilizes the surface electric field of metal nanostructures to amplify Raman signals and promote the analysis and detection of trace molecules. In order to harness the potential of flexible SERS substrates, this work proposes a simple and cost-effective method for preparing a large-area (circular, 7.5 cm in diameter, with a 38 cm2 area) three-dimensional (3D) flexible SERS substrate. We first prepared a bowl-shaped nanoarray of polydimethylsiloxane (PDMS) by utilizing a polystyrene microsphere (PS) as sacrificial templates and then loaded a monolayer of gold nanoparticles (AuNPs) on it, finally a high-strength 3D AuNPs/PDMS flexible SERS substrate is obtained successfully. There are two key steps here, which are using plasma etching to regulate the gap between PS spheres and using the thermal demolding method to facilitate the separation of PS and PDMS. The ultralarge area AuNPs/PDMS substrate exhibits high SERS detection sensitivity and good uniformity. The SERS substrate possesses the advantage of multifunctional detection. The proposed substrate demonstrated detections of up to 10–9, 10–7, and 10–8 M concentrations of rhodamine 6G (R6G), vitamin C, and thiram molecules, respectively. The detection results meet international standards. Electromagnetic simulations using the finite difference time domain reveal that the SERS enhancement originates from the surface plasmon resonance and coupling effects of AuNPs. This large-area 3D flexible SERS substrate not only enhances detection efficiency by enabling the detection of a greater number of samples or sample regions but also provides a new approach for detecting vitamin C and pesticide residues. It may also be used in electronic skin sensors, in situ pesticide residue detection, on-scene evidence collection in criminal investigations, and so on. [ABSTRACT FROM AUTHOR]

There is a growing interest in the use of flexible substrates for label-free and in situ Surface-enhanced Raman Spectroscopy (SERS) applications. In this study, a flexible SERS substrate was prepared using self-assembled Au/Ti3C2 nanocomposites deposited on a cellulose (CS) paper. The Au/Ti3C2 nanocomposites uniformly wrapped around the cellulose fibers to provide a three-dimensional plasma SERS platform. The limit of detection (LOD) of CS/Au/Ti3C2 was as low as 10−9 M for 4-mercaptobenzoic acid(4-MBA) and crystal violet (CV), demonstrating good SERS sensitivity. CS/Au/Ti3C2 was used for in situ SERS detection of thiram on apple surfaces by simple swabbing, and a limit of detection of 0.05 ppm of thiram was achieved. The results showed that CS/Au/Ti3C2 is a flexible SERS substrate that can be used for the detection of thiram on apple surfaces. These results demonstrate that CS/Au/Ti3C2 can be used for the non-destructive, rapid and sensitive detection of pesticides on fruit surfaces. [ABSTRACT FROM AUTHOR]

In recent years, the proliferation of wearable healthcare devices has marked a revolutionary shift in the personal health monitoring and management paradigm. These devices, ranging from fitness trackers to advanced biosensors, have not only made healthcare more accessible, but have also transformed the way individuals engage with their health data. By continuously monitoring health signs, from physical-based to biochemical-based such as heart rate and blood glucose levels, wearable technology offers insights into human health, enabling a proactive rather than a reactive approach to healthcare. This shift towards personalized health monitoring empowers individuals with the knowledge and tools to make informed decisions about their lifestyle and medical care, potentially leading to the earlier detection of health issues and more tailored treatment plans. This review presents the fabrication methods of flexible wearable healthcare devices and their applications in medical care. The potential challenges and future prospectives are also discussed. [ABSTRACT FROM AUTHOR]

Surface acoustic waves sensors are based on piezoelectric materials. These sensors are the best choice for sensing purposes due to their unprecedented accuracy. SAW sensors are often used in biochemical sensors, drug production, chemicals agents and gas analytes as sensing devices. These systems are extremely competitive due to their compact size, high thermal efficiency, stability, and capacity to integrate wirelessly. In the past two decades, considerable research has been conducted on the manufacturing of SAW on rigid substrates. These substrates of SAW sensors preclude their use in wearable technologies. The review will cover the research conducted on flexible saw sensors to highlight limitations in this research area for future applications sensors in wearable technology. In the end, future directions and strategies have been discussed to overcome the current challenges.

Over the past 45 years, the discovery of surface-enhanced Raman scattering (SERS), which enhances the Raman scattering of molecules absorbed on or near nanostructured metal surfaces, has brought significant potential as a powerful spectroscopic and analytical technique for various fields of ultrasensitive sensing applications. In preference to rigid substrates, recent advances in the development of flexible SERS sensors have enabled the fulfillment of practical on-site sensing and diagnostic applications with rapid and efficient sampling approaches. In this review, we summarize and discuss the most recent developments in flexible SERS substrates for on-site sensing and diagnosis over the past 4 years. We highlight the three main categories of flexible SERS sensors based on their sampling methods, including drop-and-dry, collection/swabbing, and wearable/attachable approaches. The use of substrate materials and the design of sensing platforms for sampling regarding various targets are reviewed. Finally, we discuss the challenges and perspectives of flexible SERS sensors for future developments. [ABSTRACT FROM AUTHOR]

The development of a novel and reliable surface‐enhanced Raman scattering (SERS) substrate for the surface corrosion analysis of bronze relics is an attractive research topic in cultural relic protection. A high‐performance SERS substrate was developed in the current investigation using Ag/ZIF‐8/Polyacrylonitrile (Ag/ZIF‐8/PAN) nanofibers. Silver nanoparticles were grown in situ by zeolite imidazolate framework‐8 (ZIF‐8) nanoparticles, and the substrate was examined in the surface corrosion analysis of bronze relics. In situ, growth of silver nanoparticles was ensured by the porous structure and active centers on ZIF‐8, coated on PAN nanofibers. Simultaneously, the adsorption of harmful rust‐alkaline copper chloride was enhanced on the surface of bronze relics. The extensive metal network was perturbed by the deposits, which substantially increased the intensity of the Raman characteristic peaks of the test objects. The signal strength of alkaline copper chloride at 118 cm−1 on the bronze surface increased from 1094 to 20,790. The exceptional SERS performance of silver nanoparticles with sharp edges demonstrates that the synergistic effect of ZIF‐8 nanoparticles and PAN nanofibers offers a considerable number of Raman‐enhanced hot spots. These results indicate that MOF‐based nanostructures offer a novel approach to enhancing the morphology of silver nanoparticles and expanding their potential applications in the field of cultural relic protection. [ABSTRACT FROM AUTHOR]

In this study, we aim to optimize the process for developing antireflective and refractive-index-matching films on flexible substrates. The development of these films is crucial in light of the increasing demand in the market for flexible electronics, which are poised to be the next emerging technology and application after semiconductors and flat panel displays. Our research involves the production of these films by physical vapor deposition and sputtering techniques, which can also be applied to various optical thin films. The effectiveness of our coating process has been verified and refined on the basis of feedback. The results of this study are applicable to related industrial technologies and will contribute to improving industry competitiveness. [ABSTRACT FROM AUTHOR]

Silver nanowire (AgNW) emerges as a next‐generation transparent electrode material, offering enhanced flexibility and ease of fabrication compared to traditional transparent electrode materials, such as metallic oxides. In the previous research, the uniform deposition of AgNWs on flat surfaces is demonstrated, exhibiting high conductivity, flexibility, and excellent transmittance. However, the evolution of nano‐electronics technology necessitates the fabrication of transparent electrodes on non‐flat surfaces, such as those found in zenithal bistable devices and reconfigurable Fresnel lenses. In this study, a method is proposed to deposit AgNW material on uneven surfaces using the Mylar‐bar‐coating method, with a polyvinyl chloride (PVC)‐based Fresnel lens serving as the target surface. Additionally, the impact of varying AgNW suspension concentrations on transmittance and sheet resistance is investigated. To further reduce sheet resistance, a layer of conductive polymer, poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), is deposited on the AgNWs. The measurements reveal that a 2 mg mL−1 sample exhibits a sheet resistance of 187.83 W W−1 with 87.4% transmittance at 550 nm. After the PEDOT:PSS process, the sheet resistance decreases to 122.84 W W−1 with 84.4% transmittance. In this research, a solution is offered for the uniform deposition of AgNWs on patterned surfaces, paving the way for the next generation of optical devices. [ABSTRACT FROM AUTHOR]

There is a growing interest in the use of flexible substrates for label-free and in situ Surface-enhanced Raman Spectroscopy (SERS) applications. In this study, a flexible SERS substrate was prepared using self-assembled Au/Ti3C2 nanocomposites deposited on a cellulose (CS) paper. The Au/Ti3C2 nanocomposites uniformly wrapped around the cellulose fibers to provide a three-dimensional plasma SERS platform. The limit of detection (LOD) of CS/Au/Ti3C2 was as low as 10−9 M for 4-mercaptobenzoic acid(4-MBA) and crystal violet (CV), demonstrating good SERS sensitivity. CS/Au/Ti3C2 was used for in situ SERS detection of thiram on apple surfaces by simple swabbing, and a limit of detection of 0.05 ppm of thiram was achieved. The results showed that CS/Au/Ti3C2 is a flexible SERS substrate that can be used for the detection of thiram on apple surfaces. These results demonstrate that CS/Au/Ti3C2 can be used for the non-destructive, rapid and sensitive detection of pesticides on fruit surfaces.

High‐performance, coplanar amorphous In0.5Ga0.5O (a‐IGO) thin film transistor (TFT) on a polyimide (PI) substrate deposited by spray pyrolysis (SP) is reported. The SP a‐IGO film deposited at 370 °C has less than 8% nanocrystalline‐In2O3 dots and a mass density of 6.6 g cm−3. The a‐IGO TFT on PI exhibits linear mobility over 30 cm2 V−1 s−1 and a negligible shift in threshold voltage (ΔVTH = <0.3 V) under positive bias (+20 V) at 60 °C for 1 h. The TFT performance is stable even when bent to a radius of ≈1 mm. The X‐ray photoelectron spectroscopy results of the SP a‐IGO deposited at 370 °C indicate the O‐vacancy (Vo) related defects of 25.79% and hydroxyl (OH) at less than 3%, indicating a good active/gate insulator interface. A seven‐stage ring oscillator made of SP a‐IGO TFTs exhibits a high oscillation frequency (>2.3 MHz) with a low propagation delay time of ≈30 ns per stage at a supply voltage (VDD) of 15 V. The fabricated gate shift register circuit works up to the last stage without any decrement of the input voltage (15 V) with rising and falling times less than 0.8 µs. Therefore, the coplanar a‐IGO TFT by SP deposited at 370 °C is a promising candidate for low‐cost, flexible TFT backplanes of foldable electronics. [ABSTRACT FROM AUTHOR]

In recent years, the proliferation of wearable healthcare devices has marked a revolutionary shift in the personal health monitoring and management paradigm. These devices, ranging from fitness trackers to advanced biosensors, have not only made healthcare more accessible, but have also transformed the way individuals engage with their health data. By continuously monitoring health signs, from physical-based to biochemical-based such as heart rate and blood glucose levels, wearable technology offers insights into human health, enabling a proactive rather than a reactive approach to healthcare. This shift towards personalized health monitoring empowers individuals with the knowledge and tools to make informed decisions about their lifestyle and medical care, potentially leading to the earlier detection of health issues and more tailored treatment plans. This review presents the fabrication methods of flexible wearable healthcare devices and their applications in medical care. The potential challenges and future prospectives are also discussed.

Abstract High‐performance, coplanar amorphous In0.5Ga0.5O (a‐IGO) thin film transistor (TFT) on a polyimide (PI) substrate deposited by spray pyrolysis (SP) is reported. The SP a‐IGO film deposited at 370 °C has less than 8% nanocrystalline‐In2O3 dots and a mass density of 6.6 g cm−3. The a‐IGO TFT on PI exhibits linear mobility over 30 cm2 V−1 s−1 and a negligible shift in threshold voltage (ΔVTH = 2.3 MHz) with a low propagation delay time of ≈30 ns per stage at a supply voltage (VDD) of 15 V. The fabricated gate shift register circuit works up to the last stage without any decrement of the input voltage (15 V) with rising and falling times less than 0.8 µs. Therefore, the coplanar a‐IGO TFT by SP deposited at 370 °C is a promising candidate for low‐cost, flexible TFT backplanes of foldable electronics.

Since the discovery of the low-temperature, long-range ferromagnetic order in monolayers Cr2Ge2Te6 and CrI3, many efforts have been made to achieve a room temperature (RT) ferromagnet. The outstanding deformation ability of two-dimensional (2D) materials provides an exciting way to mediate their intrinsic ferromagnetism (FM) with strain engineering. Here, we summarize the recent progress of strain engineering of intrinsic FM in 2D van der Waals materials. First, we introduce how to explain the strain-mediated intrinsic FM on Cr-based and Fe-based 2D van der Waals materials through ab initio Density functional theory (DFT), and how to calculate magnetic anisotropy energy (MAE) and Curie temperature (TC) from the interlayer exchange coupling J. Subsequently, we focus on numerous attempts to apply strain to 2D materials in experiments, including wrinkle-induced strain, flexible substrate bending or stretching, lattice mismatch, electrostatic force and field-cooling. Last, we emphasize that this field is still in early stages, and there are many challenges that need to be overcome. More importantly, strengthening the guideline of strain-mediated FM in 2D van der Waals materials will promote the development of spintronics and straintronics. [ABSTRACT FROM AUTHOR]

In this article, we present the procedure of preparation of flexible electronic paper with a photosensitive azo dye layer as the key element for changing the orientation of the polarization plane. The main steps of the technology for the fabrication of flexible e-paper are reported. The possible production of Digital Mirror Devices and the roll-to-roll process is discussed. Images on flexible e-paper are demonstrated, including bank card options. The advantages of optically rewritable e-paper technology in comparison with the e-ink usually used for this purpose are highlighted. Potential applications of flexible optically rewritable e-paper include price tags for supermarkets, indoor and outdoor advertisements, smart card labels, etc. [ABSTRACT FROM AUTHOR]

Abstract In this work, the fabrication of multilayered transparent conductive oxides (TCOs), ZnO–Ag–ZnO (Z-TCO) and AZO–Ag–AZO (AZ-TCO), on flexible polyethylene terephthalate (PET) substrate using radio frequency (RF) magnetron sputtering is reported, with the optical and electrical properties comparable to those of the commercially available Sn-doped indium oxide (ITO) on the PET substrate. The growth of Z-TCO and AZ-TCO layers on PET (with surface roughness ~5 – 7 nm) shows similar surface characteristics to that on the glass substrate. The multilayered Z-TCO and AZ-TCO (total thickness ~70 nm) with 10 nm of Ag thickness (named Z-2 and AZ-2, respectively) exhibit a maximum transparency of 82.7% and 86.4%, at 515 and 498 nm, respectively. The AZ-2 layer has a lower electrical resistivity of 3.92 × 10−5 Ω cm with a lower sheet resistance of 5.6 Ω/sq, whereas for ITO on PET these values are 2.62 × 10−4 Ω cm and 14.5 Ω/sq, respectively. The AZ-2 layer also gives an excellent figure of merit (FoM) of 21.3 × 10−3 Ω−1, which is better than the FoM for ITO PET (17.3 × 10−3 Ω−1). Therefore, the flexible multilayer TCOs prepared using RF magnetron sputtering on PET substrates on a large area can have better optoelectronic properties than commercial flexible ITO coating and can be used in flexible optoelectronic devices.

Ag-27.9 at% Co-8.9 at% Zr alloy films were deposited on flexible polyimide (PI) by magnetron sputtering and annealed in argon atmosphere. Results show that many fine nanoparticles are formed on the surface of as-deposited Ag–Co–Zr alloy films. Furthermore, the average size of self-formed Ag nanoparticles gradually increases while the number of Ag nanoparticles decreases as alloy film thickness increases. In addition, it is worth noting that flake-like and polyhedral nanoparticles are formed spontaneously on the surface of annealed alloy films and are proved to be single crystal Ag nanoparticles. Moreover, the morphology of flake-like Ag nanoparticles is dependent on annealing temperature. In order to improve “hotspots” activity of the alloy films, a 12 nm pure Ag layer was deposited on the annealed alloy film surface to obtain Ag layer/Ag nanoparticles/Ag–Co–Zr alloy films SERS substrates which can detect 5 × 10−14 M R6G. This paper provides a potential candidate for preparation of SERS substrates with ultra-high sensitivity and stability.

Laser patterning to fabricate micro/nanoscale structures attracts enormous attention as they find many functional applications owing to their controllable structure and unique properties. The present work proposes a unique solution‐based method to fabricate laser‐induced periodic surface structure (LIPSS) patterns on a thin film of Titanium (IV) butoxide and Ag organometallic (OM) solution‐coated glass substrates with near infra‐red (NIR) nanosecond (ns) laser. The formation of periodic patterns has been confirmed, the thin film solution concentration affects the LIPSS pattern thickness and a continuous pattern is achieved with the diluted solution. Parametric studies demonstrate that the LIPSS patterns could be achieved with optimal solution dilution, laser fluence, scan speed, and pulse duration. A high power and faster scan speed result in discontinued, and defective patterns. The photothermal process such as material reorganization followed by electromagnetic absorption that takes place during laser patterning is mainly responsible for the fabrication of controlled structures. LIPSS patterned surfaces exhibit iridescent surface coloration while illuminated with white light, and the color spectrum from red to blue is distinguished. LIPSS patterned substrates serve as mold and structures are transferrable to the poly dimethyl siloxane (PDMS) film and exhibit iridescent structural coloration like LIPSS patterned substrates. [ABSTRACT FROM AUTHOR]

Flexible electronics have seen extensive research over the past years due to their potential stretchability and adaptability to non‐flat surfaces. They are key to realizing low‐power sensors and circuits for wearable electronics and Internet of Things (IoT) applications. Semiconducting metal‐oxides are a prime candidate for implementing flexible electronics as their conformal deposition methods lend themselves to the idiosyncrasies of non‐rigid substrates. They are also a major component for the development of resistive memories (memristors) and as such their monolithic integration with thin film electronics has the potential to lead to novel all‐metal‐oxide devices combining memory and computing on a single node. This review focuses on exploring the recent advances across all these fronts starting from types of suitable substrates and their mechanical properties, different types of fabrication methods for thin film transistors and memristors applicable to flexible substrates (vacuum‐ or solution‐based), applications and comparison with rigid substrates while additionally delving into matters associated with their monolithic integration. [ABSTRACT FROM AUTHOR]

The giant magnetoimpedance effect of multilayered thin films under stress has great application prospects in magnetic sensing, but related studies are rarely reported. Therefore, the giant magnetoimpedance effects in multilayered thin film meanders under different stresses were thoroughly investigated. Firstly, multilayered FeNi/Cu/FeNi thin film meanders with the same thickness were manufactured on polyimide (PI) and polyester (PET) substrates by DC magnetron sputtering and MEMS technology. The characterization of meanders was analyzed by SEM, AFM, XRD, and VSM. The results show that multilayered thin film meanders on flexible substrates also have the advantages of good density, high crystallinity, and excellent soft magnetic properties. Then, we observed the giant magnetoimpedance effect under tensile and compressive stresses. The results show that the application of longitudinal compressive stress increases the transverse anisotropy and enhances the GMI effect of multilayered thin film meanders, while the application of longitudinal tensile stress yields the opposite result. The results provide novel solutions for the fabrication of more stable and flexible giant magnetoimpedance sensors, as well as for the development of stress sensors. [ABSTRACT FROM AUTHOR]

3D printing technology combined with thermoplastic polyurethane (TPU) is increasingly being used in flexible electronics. However, the defects induced by 3D printing may degrade the mechanical properties of the TPU substrates significantly and result in the decrease in breaking elongation, tensile strength, and waterproof performance. In this article, we investigate the effect of heat treatment on improving the mechanical and waterproof properties of TPU substrate experimentally. The results show that heat treatment can effectively reduce the defects such as bubbles and pores inside the 3D printed TPU structure and increase the bonding area of the filament, and thus making the 3D printed TPU structure dense. After heat treatment at 180°C, the tensile strength and elongation at break of 3D printed TPU samples in the fiber direction (filling angle of 0°) increased by 67% and 38%, respectively. The tensile strength and elongation at break in the bonding direction (filling angle of 90°) increased by 100% and 75%. In addition, the waterproof performance of the samples has been enhanced, and the water contact angle of the surface has increased from 90.4°to 95.25°. Therefore, the heat treatment can effectively improve the mechanical properties and waterproof performance of 3D printed TPU samples. [ABSTRACT FROM AUTHOR]

The developments in inkjet printing technology and the printed electronics industry in the past two decades have provided cost-effective, environmentfriendly, and reliable alternates to traditional methods of fabricating electrical devices. However, most commercial metallic inks require high sintering temperatures to form desired functional patterns, which limits the applications of printed electronics in scenarios that require electrical devices on thermally sensitive substrates, like biomaterials or bio-synthetic composite materials. This study provides the synthetic route of a novel silver-based metal organic decomposition (MOD) ink which is used to form highly conductive silver films on the thermally sensitive skin-inspired silk/epoxy composite substrates by directly inkjet printing with accurate pattern control, whilst self-decomposing and sintering at room temperature. The fabricated silver patterns on the thermally sensitive silk/epoxy composite substrate are highly conductive with conductivity of 4.65 × 104 S m-1. These silver patterns also show impressive malleability as bulk silver films, which can be further developed into motion sensors for wearable devices or medical applications. Our strategy provides a general platform for electronic functionalization without temperature constraints. The particle-free, reactive silver-precursor, and lower sintering temperature of the ink also widen the choices of substrates, as exemplified herein with outstanding printing quality and high electrical conductivity (1.20 × 106 S m-1) also achieve on paper. [ABSTRACT FROM AUTHOR]

The exploitation of natural materials has received growing attention because of the needs of environmental sustainability. In contrast to petroleum‐based synthetic materials, natural materials possess significant advantages of abundant, low‐cost, degradable, and renewable. Here, the recent research status of natural materials as flexible substrate, cathode interfacial material, and anode interfacial material for organic photovoltaics (OPVs) are first presented. Then, the confronted key challenges that limit the widespread application of natural materials for OPVs is summarized, including complex multilength scaled aggregation morphology, non‐conjugated structure, and unclear working mechanism. Finally, their potential solutions from the perspective of chemical structure are proposed for constructing efficient OPVs. It is believed that natural materials have a broad landscape in low‐cost and green manufacturing technology for OPVs in the future. [ABSTRACT FROM AUTHOR]

GnP doped Al 2 O 3 flexible tapes were produced through Tape Casting technique and used as substrates to produce Co 2 FeAl/GnP doped Al 2 O 3 heterostructures. The Co 2 FeAl layers were grown using Magnetron Sputtering with a thickness of 30 nm. The integration of Tape Casting and Magnetron sputtering techniques allowed us to explore the thermomagnetic properties of the heterostructure through the Anomalous Nernst Effect. The structural and morphological properties of the substrates and the magnetization curves support the thermomagnetic results. The Co 2 FeAl ferromagnetic films presented isotropic magnetic behavior, which was reflected in the thermomagnetic curves through the stability of the curve's shape irrespectively of the thermal gradient and angle of the external magnetic field used during the measurements. Our findings open new possibilities to produce flexible heterostructures with multifunctional properties, where the versatilities of the Tape casting and magnetron sputtering techniques bring new routes to build nanostructured materials. [ABSTRACT FROM AUTHOR]

Perovskites have already shown potential as active layers in photovoltaic applications. Furthermore, a low-cost and simple solution processing technology allows perovskites to be used in flexible and printed electronics. Perovskite solar cells (PSC) with a back-contact (BC) structure, in which the electrode system is based on a quasi-interdigitated back-contact (QIBC) design, promise to increase the power conversion efficiency (PCE) of devices beyond those that can be obtained using PSCs with a traditional sandwich structure. While the spin-coating technique is used to deposit the perovskite layer of lab-scale BC PSCs, the application of large-area printing techniques to deposit the perovskite layer of such devices is yet to be explored. Therefore, this work demonstrates an application of the slot-die coating technique to print the perovskite active layer of BC PSCs with QIBC electrodes on flexible polymer substrates. The morphology of the obtained perovskite films on QIBC electrodes are investigated and the primary photoelectric parameters of the resulting BC PSCs are measured. The charge carrier recombination processes in the fabricated BC PSCs are investigated and the dominant mechanism for carrier loss in the devices is determined. The findings of the work give an insight into the properties of the slot-die-coated perovskite active layer of BC PSCs and points to exciting new research opportunities in this direction. [ABSTRACT FROM AUTHOR]

In recent decades, thriving Internet of Things (IoT) technology has had a profound impact on people's lifestyles through extensive information interaction between humans and intelligent devices. One promising application of IoT is the continuous, real-time monitoring and analysis of body or environmental information by devices worn on or implanted inside the body. This research area, commonly referred to as wearable electronics or wearables, represents a new and rapidly expanding interdisciplinary field. Wearable electronics are devices with specific electronic functions that must be flexible and stretchable. Various novel materials have been proposed in recent years to meet the technical challenges posed by this field, which exhibit significant potential for use in different wearable applications. This article reviews recent progress in the development of emerging nanomaterial-based wearable electronics, with a specific focus on their flexible substrates, conductors, and transducers. Additionally, we discuss the current state-of-the-art applications of nanomaterial-based wearable electronics and provide an outlook on future research directions in this field. [ABSTRACT FROM AUTHOR]

A unique deposition approach combining atomic layer deposition (ALD) and magnetron sputtering was used to fabricate a series of thin film multilayer structures of Al (50 nm) and Al2O3 (ALD, 2.4–9.4 nm) on flexible polymer substrates without breaking vacuum. The multilayers together with 50 nm and 150 nm Al reference films were analyzed by cross-sectional TEM analysis and experimentally strained in biaxial tension to investigate their deformation behavior. Al film stresses and peak widths, measured in situ with Synchrotron X-ray diffraction, are in good agreement with post-mortem surface SEM and through-thickness FIB analysis of the multilayers. It was revealed that brittle cracking of the multilayer can be avoided, and that the lateral and through-thickness crack resistance improve as a function of decreasing oxide layer thickness. An attempt to model the full biaxial yield surface of the multilayers, which remains experimentally challenging, appears to be valid up to 2.4 nm oxide thickness. Model predictions are further compared to compression data, obtained from the unloading segments of the tensile tests. Describing the mechanical behaviour under multiaxial stress conditions is of utmost importance for a diverse understanding of these multilayers across a variety of potential carrier systems and loading cases.

This article describes the performance analysis of the fabricated visible photodetector based on the Pd/pentacene/ZnO/ITO/PET structure. Hydrothermal and thermal vacuum deposition techniques deposited the ZnO and pentacene films, and FESEM images examined the topology of the deposited films. The I-V characteristics of a device were assessed in both dark and light environments throughout a voltage range of −5 to 5 V. With the help of Cheung's method and the standard thermionic emission theory, electrical performance parameters in the dark mode were extracted. The barrier height and ideality factor for the thermionic emission test were 0.784 eV and 2.19, respectively. In contrast, the barrier height and ideality factor for the Cheung technique was found to be 0.77 eV and 1.4, respectively. This research demonstrates Cheung's approach, which accounts for series resistance 692.46 Ω. The proposed photodetector exhibits a high gain of 579 and responsivity of 279 A/W.

Reduced graphene oxide (rGO) is a derivative of graphene, which has been widely used as the conductive pigment of many water-based inks and is recognized as one of the most promising graphene-based materials for large-scale and low-cost production processes. In this work, we evaluate a custom functionalised reduced graphene oxide ink (f–rGO) via inkjet-printing technology. Test line structures were designed and fabricated by the inkjet printing process using the f–rGO ink on a pretreated polyimide substrate. For the electrical characterisation of these devices, two-point (2P) and four-point (4P) probe measurements were implemented. The results showed a major effect of the number of printed passes on the resulting resistance for all ink concentrations in both 2P and 4P cases. Interesting results can be extracted by comparing the obtained multipass resistance values that results to similar effective concentration with less passes. These measurements can provide the ground to grasp the variation in resistance values due to the different ink concentrations, and printing passes and can provide a useful guide in achieving specific resistance values with adequate precision. Accompanying topography measurements have been conducted with white-light interferometry. Furthermore, thermal characterisation was carried out to evaluate the operation of the devices as temperature sensors and heaters. It has been found that ink concentration and printing passes directly influence the performance of both the temperature sensors and heaters. [ABSTRACT FROM AUTHOR]

Ion‐sensitive field‐effect transistors (ISFETs) are electrochemical sensors that work on the principle of metal‐oxide field‐effect transistors. Dual‐gate ion‐sensitive field‐effect transistors (DGISFETs) are an advanced version of ISFETs with an additional gate dielectric, resulting in sensitivity enhancement on account of the coupling of the capacitances of the two gate dielectrics. ISFETs were demonstrated first in 1970 and there are several review articles available on various aspects of ISFETs; although DGISFETs were first demonstrated in 2010, there are no focused review articles on this subject and this is the motivation of present work. This review has explored the understanding of the basic platform, the working principle, different structures, and various applications of DGISFETs. Further, types of DGISFETs are elaborated based on their architecture, material used for fabrication, and substrates used for such devices with utilization of different semiconductor and gate dielectric materials, rigid and flexible substrates. The state‐of‐the‐art of rigid and flexible DGISFETs is discussed for various applications. Challenges in the fabrication and utilization of DGISFETs in various fields and further advances are discussed. [ABSTRACT FROM AUTHOR]

Lactate, a crucial product of the anaerobic metabolism of carbohydrates in the human body, is of enormous significance in the diagnosis and treatment of diseases and scientific exercise management. The level of lactate in the bio-fluid is a crucial health indicator because it is related to diseases, such as hypoxia, metabolic disorders, renal failure, heart failure, and respiratory failure. For critically ill patients and those who need to regularly control lactate levels, it is vital to develop a non-invasive wearable sensor to detect lactate levels in matrices other than blood. Due to its high sensitivity, high selectivity, low detection limit, simplicity of use, and ability to identify target molecules in the presence of interfering chemicals, biosensing is a potential analytical approach for lactate detection that has received increasing attention. Various types of wearable lactate biosensors are reviewed in this paper, along with their preparation, key properties, and commonly used flexible substrate materials including polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), paper, and textiles. Key performance indicators, including sensitivity, linear detection range, and detection limit, are also compared. The challenges for future development are also summarized, along with some recommendations for the future development of lactate biosensors. [ABSTRACT FROM AUTHOR]

The popularity of health concepts and the wave of digitalization have driven the innovation of sensors in the medical field. Such continual development has made sensors progress in the direction of safety, flexibility, and intelligence for continuous monitoring of vital signs, which holds considerable promise for changing the way humans live and even treat diseases. To this end, flexible wearable devices with high performance, such as high sensitivity, high stability, and excellent biodegradability, have attracted strong interest from scientists. Herein, a review of flexible wearable sensors for temperature, heart rate, human motion, respiratory rate, glucose, and pH is highlighted. In addition, engineering issues are also presented, focusing on material selection, sensor fabrication, and power supply. Finally, potential challenges facing current technology and future directions of wearable sensors are also discussed. [ABSTRACT FROM AUTHOR]

AZO (Al-doped ZnO) film is a transparent conductive film that offers a simple preparation process, low cost, non-toxicity, and excellent stability. It serves as a high-quality material extensively used in liquid crystal displays, solar cells, and other fields. In this study, AZO thin films were prepared on a PET substrate with an Al 2 O 3 buffer layer using the magnetron sputtering method. The deposition parameters were optimized through the Taguchi method and Grey Correlation Analysis. The results demonstrate that the optimal deposition parameters for achieving superior photoelectric properties during the fabrication of AZO films are 100 W (radio frequency power), 1.0 Pa (sputtering pressure), 20 min (coating time), and 20 °C (substrate temperature). Furthermore, the incorporation of an Al 2 O 3 buffer layer enhances the quality of AZO film on PET substrate. This investigation successfully deposited uniform and highly efficient AZO thin films onto flexible PET substrates at low temperatures, thereby expanding their potential applications in flexible electronics. • Optimized process parameters for AZO films scientifically analyzed. • Al-based buffer layer enhances optical properties of AZO films. • Data support for sputtering AZO films with buffer layer on flexible substrates. [ABSTRACT FROM AUTHOR]

Flexible substrates, essential for flexible electronics by providing support and flexibility while influencing sensor stability, still face challenges in achieving mechanical and thermal stability, particularly in large-scale production and cost control. Inspired by the nacre's "brick-and-mortar" hierarchical microstructure, this study introduces PPSN (paper/polydimethylsiloxane (PDMS)/Si₃N₄ nanoparticles), a novel flexible substrate that mimics the "brick-and-mortar" structure. PPSN, with its topological interlocking and assembly technique, provides excellent thermal and mechanical stability, including high-temperature resistance and stress dissipation. An optimized Si₃N₄ content of 1.0 wt% yields a peak elastic modulus of 1245.27 MPa while maintaining hydrophobicity, with a contact angle of 127.1° at 3.0 wt%. The substrate shows excellent fatigue durability, retaining its morphology after 10,000 bending cycles. Thermal analysis indicates a stable CTE below 20 ppm/°C up to 300°C, rising to 200 ppm/°C between 350 and 400°C. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) reveal minimal thermal decomposition with mass loss below 0.5 % from 25 to 300°C and under 3 % at 400°C. Additionally, electrodes were printed on the substrate using screen printing and ion beam deposition (IBD), demonstrating good material adhesion. A flexible temperature sensor was fabricated and exhibited good sensitivity and stability with a TCR of −0.262 % °C⁻¹. PPSN advances traditional materials with superior mechanical strength, thermal stability, and durability, offering significant scientific and practical value for flexible electronics and low-cost biomimetic processes. [Display omitted] • PPSN mimics nacre's structure, offering high thermal and mechanical stability. • Peak elastic modulus at 1.0 wt% Si₃N₄, with hydrophobicity and durability. • Stable CTE below 20 ppm/°C up to 300°C with minimal thermal mass loss. • Excellent performance in flexible sensors with a TCR of −0.262 % °C⁻¹. [ABSTRACT FROM AUTHOR]

Chronic renal insufficiency has been a high-incidence disease around the world in recent years. With the lack of devices to detect these illnesses opportunely, developing urea biosensors is imperative. This work reports the application of copper sulfide (CuS) thin films deposited via a chemical bath and Bioglass 45S5/titanium dioxide nanoparticles thin films in a urea flexible biosensor. The Bioglass 45S5 was deposited over CuS and applied onto polyethylene naphthalate (PEN) and polyethylene terephthalate (PET) with indium tin oxide (ITO) substrates. The systems PEN/CuS/Bioglass 45S5.TiO 2 NpS and PET/ITO/CuS/ Bioglass 45S5.TiO 2 were characterized optically by UV-Vis. The CuS presented an absorption border around 600 nm and a decrease in transmittance percentage by adding Bioglass. Scanning Electron Microscopy carried out the microstructural characterization; both systems displayed a porous morphology featuring channels suitable for immobilizing the enzyme. The sensors showed a resistive behavior based on the current-voltage curve. The urease enzyme was immobilized by adsorption. The optical changes after adding urease were measured by UV-Vis, obtaining ammonia from the reaction between urease and urea, showing an absorption border around 850 nm. Changes in urea concentrations between 1 and 10 mM caused an increase in resistivity in both samples, obtaining a sensitivity of 12.887 kΩ/sq/mM and 12.411 kΩ/sq/mM, and a linearity of 0.9946 % and 0.9601 % for the samples deposited over PEN and PET ITO, respectively. A Cole-Cole plot showed a behavior corresponding to an equivalent circuit composed of a parallel combination of a resistor and a capacitor in series with a phase constant element; this latter could be attributed to the measurement electrodes. Each sensor was implemented in a Wheatstone bridge. A voltage decrease was obtained for the sample deposited over PET ITO, with a sensitivity of −102.7 mV/mM, and a voltage increase was obtained in the sample deposited over PEN, with a sensitivity of 30.5 mV/mM. • CuS and Bioglass thin films interface was deposited homogeneously. • CuS showed a semiconductor behavior, bioglass is a dielectric. • Thin films showed an optical and chemical response with the addition of urea. • Thin films showed a resistance increment proportional to urea concentration. [ABSTRACT FROM AUTHOR]

Perovskite photovoltaics (PPVs), renowned for their high efficiency in dim indoor illumination conditions, cost-effective manufacturing processes, and compatibility with flexible substrates, emerge as a superior choice over traditional photovoltaics (PVs) for Internet of Things (IoT) applications, contributing to the advancement of eco-friendly energy initiatives. While flexible PPVs (f -PPVs) boast significant advantages over traditional PV technologies; there's a notable scarcity of reports focusing on their performance in indoor settings. The timely review underscores recent advancements in f -PPVs, aiming for their seamless integration into IoTs. It extensively explores crucial metrics in dim indoor lighting conditions, centering on indoor light source types, optimum functionality with perovskite passivation, and the optimization of bandgap and an ideality factor to achieve improved performance in indoor f -PPVs. Furthermore, it examines the strategies for improving the efficiency and stability of f -PPVs, with a pivot focus on selecting suitable flexible substrates and fabrication techniques conducive to mass-scale production. Besides, the significance of promoting eco-friendly IoT devices is emphasized by eliminating toxic materials and solvents from the device fabrication process. Finally, the review tackles pressing challenges and offers guidelines for the development of efficient and stable f -PPVs, aiming to facilitate their commercialization within the IoT ecosystem. [Display omitted] • The review unlocks potential of indoor flexible perovskite photovoltaics (f -PPV) for IoTs. • The review systematically discusses crucial metrics in dim indoor lighting conditions. • Eco-friendly fabrication and stability of f -PPVs are emphasized. • Unleashing challenges and prospects for f -PPVs in indoor energy harvesting. [ABSTRACT FROM AUTHOR]

Objective: Wound dressings that create and maintain a moist environment provide the optimal conditions for wound healing by increasing the rate of epithelialization and angiogenesis. However, current wound dressings require periodic removal which exposes the wound to the surrounding environment, thereby increasing the likelihood for infection and drying out the wound itself. There remains an unmet medical need for the development of an absorbent, flexible, and transparent wound dressing that can conform to the irregular geometry of the wound for a long-term duration. Herein, we report the development of AFTIDerm, an Absorbent, Flexible, Transparent, and Inexpensive moisture-management wound dressing using Polyvinyl alcohol (PVA) as the host material. Methods: AFTIDerm substrates of varying glycerol concentrations (1 wt%, 3 wt%, 5 wt%, 7 wt%, and 10 wt%) were fabricated and tested. The mechanical, absorption, and biological properties of AFTIDerm were evaluated. Results: We found that 5% glycerol served as the optimal concentration for AFTIDerm. The biocompatibility, absorptive capabilities, and scalability render PVA/glycerol an ideal material composition for wound dressings. Benchtop experimentation and pre-clinical testing demonstrate AFTIDerm as a platform for use in wound dressings. Discussion/Conclusion: The development of AFTIDerm broadens the translational utility of this materials platform not only as a material for wound dressings to minimize dressing changes in low to moderate exudate environments, but also as a potential substrate material for smart bandages. Clinical and Translational Impact Statement— AFTIDerm, an absorbent, flexible, and transparent wound dressing, maintains the moist environment required for healing while enabling monitoring of healing without removal and disruption to the wound bed.

The next generation of green electronic products will be flexible, eco‐friendly, have arbitrary patterning, and be produced using simple methods. Here, a silver nanoparticles (Ag NPs)–graphite carbon composite‐based electrochemical sensor is patterned on a flexible substrate by one‐step in situ femtosecond (fs) laser fabrication. Alkali lignin is used as a precursor and nontoxic natural reducing agent to reduce aqueous silver nitrate to produce Ag NPs. The fs laser carbonization process converts lignin into graphite carbon electrodes with diverse three‐dimensional (3D) micro/nano morphologies, causing less thermal damage to the Ag NPs and thin substrate. The 3D micro/nano morphologies combined with Ag NPs effectively increase the active surface area, conductivity, and catalytic activity of the electrode, which is further applied as an electrochemical sensor. This sensor has a wide linear detection range of nitrite from 1–4000 × 10−6 m, a detection limit of 0.117 × 10−6 m (S/N = 3), and long lifetime of 30 days. The sensor also has the potential to detect dopamine (DA). A detection limit of 0.098 × 10−6 m (S/N = 3) is obtained, with a linear detection range of 1–45 × 10−6 m. The sensor demonstrates a wide range of applications in food safety and human health‐related detection. [ABSTRACT FROM AUTHOR]

Flexible perovskite solar cells (PSC) represent a viable technology for applications requiring high power‐to‐weight ratios, seamless integration onto a variety of shapes, and low embedded energy. Strategies to boost the performance of flexible PSC, which still lag behind their rigid counterparts, include passivation of the perovskite surface with ammonium salts. Herein, the optimization of low‐temperature solution‐processed phenethylammonium iodide (PEAI) layers to passivate triple‐cation perovskite films as an effective strategy for flexible planar PSCs is reported. The best PEAI‐passivated cell delivers a maximum power conversion efficiency of 15.2% in forward scan, which is 22% higher in relative terms compared with nonpassivated devices, due to a major improvement in both open‐circuit voltage and fill factor. Optoelectrical characterization highlights that PEAI films effectively reduce trap‐mediated charge recombination, without hindering charge transport across the perovskite/hole transport layer interface. Light‐soaking stability of nonencapsulated cells with PEAI layers is also greatly enhanced, retaining 80% of the initial power conversion efficiency for twice as long as the reference devices, therefore proving the potential of this material for the development of efficient and durable flexible PSCs. [ABSTRACT FROM AUTHOR]

Perovskite Solar Cells (PSCs) are well known for their high efficiencies under 1 sun (AM1.5G), however, PSC can also generate power by harvesting the low‐light available indoors. Here, three flexible PSC architectures are presented for indoor applications: with a metal electrode aiming for high efficiency; carbon electrode aiming for high stability and compatibility with large‐scale production; and hole transport material (HTM)‐free carbon for simplifying the fabrication process. A maximum efficiency of 30.9% (30.0%) under 1000 lux (200 lux) is obtained for a PSC with gold electrode. A maximum efficiency of 25.4% (24.7%) and 23.1% (22.3%) is obtained for the carbon devices with and without HTM, respectively, under 1000 lux (200 lux). To the best of the author's knowledge, the efficiency values presented here for a device with a carbon‐based electrode, with and without HTM, are the record values for a flexible PSC at indoor light conditions. Furthermore, the HTM‐free carbon device kept 84% of its initial efficiency after 1000 h at MPPT and lost virtually no performance after 1000 h at 85 °C. Also, non‐encapsulated devices of all configurations withstood 1600 h in air with a maximum loss in efficiency of 6%. [ABSTRACT FROM AUTHOR]

Due to the increasing importance of food quality/safety control, there is an imminent need to develop efficient methods for the rapid detection of pesticide residues in agricultural products. Herein, we proposed a simple and rapid detection approach to the in situ detection of residual pesticides on fruit/vegetable using surface-enhanced Raman spectroscopy (SERS). Flexible and transparent SERS substrates were fabricated by transferring Au@Ag core-shell nanorods (Au@Ag NRs) arrays to silicone membranes, with the single-layer Au@Ag NRs arrays prepared by the liquid–liquid interface self-assembly method. The as-prepared SERS sensor showed excellent SERS activity and repeatability, and it could be readily pasted onto the surface of fruit and vegetables for residual pesticide detection. For the inspection of thiram in contaminated strawberries, apples, and mushrooms, the limit of detection (LOD) could reach 2 ng/cm2 with high measurement recovery and reproducibility. In general, this work provides an effective way for the preparation and application of flexible and transparent SERS substrates in food-safety control. [ABSTRACT FROM AUTHOR]

Plasmonic nanostructures, due to their extremely strong confinement and enhancement of optical field, have emerged as a potential tool in myriad applications, ranging from nano‐laser to surface‐enhanced Raman scattering (SERS) and biosensing. To break through the restriction of intrinsic losses and radiative damping in metal nanostructures resulting in broad plasmon resonance, a plasmonic nanostructure sensor employing hexagonal nanopillar array on flexible substrate to form the bilayer gold cap‐hole coupling structure is proposed and demonstrated. The sensor is fabricated by the combination of vacuum coating and template transfer, and experimentally exhibits an ultranarrow plasmon resonance coupling mode with a linewidth of 4.5 nm. Such a sharp linewidth resonance originates from the coupling of geometrical‐induced Wood's anomaly (WA) and Fabry–Perot (FP) modes. Benefiting from this ultranarrow resonance, a figure of merit (FOM) of 140.6 and spectroscopic detection noise down to 0.02 nm are demonstrated in the bulk refractive index (RI) sensing. Furthermore, the nanopillar array enables the detection of bovine serum albumin biomolecular with the detection limit of 0.27 µm. The plasmonic array device can be further investigated for more potential practical utility that are valuable and significant for label‐free biomolecular sensing with high sensitivity and high throughput. [ABSTRACT FROM AUTHOR]

Developing surfaces that effectively repel low-surface-tension liquids with tunable adhesive properties remains a pivotal challenge. Micronano hierarchical re-entrant structures emerge as a promising solution, offering a robust structural defense against liquid penetration, minimizing area fraction, and creating narrow gaps that generate substantial upward Laplace pressure. However, the absence of an efficient, scalable, and tunable construction method has impeded their widespread applications. Here, drawing inspiration from springtail epidermal structures, octopus suckers, and rose petals, we present a scalable manufacturing strategy for artificial micronano hierarchical T-shaped structures. This strategy employs double-transfer UV-curing nanoimprint lithography to form nanostructures on microstructured surfaces, offering high structural tunability. This approach enables precise control over topography, feature size, and arrangement of nano- and microscale sections, resulting in superamphiphobic surfaces that exhibit high contact angles (>150°) and tunable adhesive forces for low-surface-energy liquids. These surfaces can be applied to droplet-based microreactors, programmable droplet-transfer systems, and self-cleaning surfaces suitable for various liquids, particularly those with low surface tension. Remarkably, we have also succeeded in fabricating the hierarchical structures on flexible and transparent substrates. We demonstrate the advantages of this strategy in the fabrication of hierarchical micronanostructures, opening up a wide range of potential applications.