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Metal halide perovskite quantum dots (QDs) with unique physicochemical properties are promising candidates for next-generation optoelectronics, but they often suffer from stability issues that severely limit their potential for practical applications. In this work, we adopt an oleic acid/oleylamine-free approach to synthesize MAPbBr3 quantum dot (MQD) papers by incorporating MQDs into cellulose nanofiber frameworks. The abundant long-chain binding ligands containing sulfate terminal groups within the cellulose nanofiber remarkably stabilize the MQD structure, enabling the fabrication of self-power and flexible MQD paper photodetectors with a responsivity of ∼0.19 mA W−1, detectivity of 1.58 × 108 cm Hz1/2 W−1, and excellent bendability and reliability after 500 bending cycles. More importantly, these MQD/cellulose-based self-powered photodetectors demonstrate extraordinarily high environmental stability, maintaining more than 90% of the initial responsivity after 60 days. The simple disposability of the paper-based device is also illustrated by burning within one second, suggesting the ease of device elimination. Our work provides a unique approach to designing ultra-stable perovskite QD-based electronics with unprecedented functionalities. [ABSTRACT FROM AUTHOR]

Hygroscopic cellulose office papers possess the ability to absorb water or moisture, resulting in enhanced electrical conductivity. This study demonstrates the utilization of humidified office papers as versatile, disposable, and renewable broadband photodetectors for diverse applications. The developed paper-photodetectors (P-PDs) allow simultaneous detection of broadband light and temperature. By effectively controlling and managing the water content, sealed office papers offer reliable detection of both visible and UV light, along with temperature measurements. Notably, they are characterized by flexibility, scalability, eco-friendliness, and cost-effectiveness. [ABSTRACT FROM AUTHOR]

In this work, paper-based flexible X-ray detectors were developed. Outstanding detection performance and high stability were realized by combining the intrinsic flexibility of the PbI2 nanocrystal, and the bendability of cellulose fiber paper. The devices were prepared using a scalable solution infiltration method and a screen-printing method. The PbI2 nanocrystal was coating onto the fiber instead of filling the micropore between the fibers. This special microstructure suppresses the effect of the carrier lateral diffusion by restricting the transport of the photoexcited carriers along the longitudinal direction of fibers, which promotes carrier transport, and improves photodetection performance. All of the pixels showed a high consistency of sensitivity, and a high signal-to-noise ratio, which ranged from 76.7 to 78.3 mC Gy-1 cm-2, and 296.4 to 327.3, respectively. In addition, benefitting from the unfilled micropores which serve as a stress buffer zone, the devices reveal high flexibility when the composite structure is in tension or compression. After 1000 bending cycles, no cracks were found in the nanocrystalline layer on the fibers, and the photocurrent was maintained at over 87%. In addition, a linear array X-ray imager was successfully implemented using the as-fabricated devices. [ABSTRACT FROM AUTHOR]

Inkless photonic paper has shown great potential as an alternative to traditional paper due to its unique structural color, which is dye-free and non-photobleaching. However, it is still highly challenging to produce large-area photonic crystal paper, and its angle dependence, complicated printing procedure, and difficulty of high-resolution printing have greatly limited its applications. To address these challenges, we developed a new UV printing strategy using amorphous structured inverse opal PEGDA photonic paper. The photonic paper is prepared using an amorphous assembly of colloidal SiO2 particles as templates, which are fabricated by spray coating dispersions of SiO2 particles with the addition of carbon black. The photonic paper possesses structural color with low angle independency when the observation angle varies from 0° to 40°, and the unvivid structural color can be tuned in the whole visible region by exposure to UV radiation for different amounts of time, providing a fast, convenient and high-resolution printing technique. Through a chromatic-printing-like method using a series of different masks, multi-color printing is also realized. The printed images can be further protected from UV irradiation using a layer of PET film, which provides a method to store the printings for a longer time in a harsh environment. [ABSTRACT FROM AUTHOR]

The pressing priority for flexible photo-responsive systems is scalability and simplistic fabrication routes at low production costs. The extraordinary properties seen in 2D materials, paired with solution-processing advantages, assert their employability for superior photoresponsive systems. Herein, we demonstrate versatile and flexible photodetectors and photo-thermal actuators by integrating 2D materials onto paper substrates. All-solution processed flexible photodetectors have been fabricated by spray coating dispersions of MoS2 nanosheets onto screen printed carbon electrodes. By employing MoSe2 as a photothermal conversion layer, actuators with paper-tape bilayers have also been demonstrated. For both photoresponsive applications, the process of calendering investigated in detail results in remarkable augmentation of the performances. Real-world thermally stimulated soft robotic applications like jacks, grippers and crawlers are realized by leveraging a configuration dependent response to illumination. Thus, a well-structured and feasible implementation of a chain of protocols that includes screen printing, spray coating, lamination and calendering with paper as the substrate led us to fabricate flexible photoresponsive systems with significantly enhanced performances. [ABSTRACT FROM AUTHOR]

The design of the three-dimensional (3D) porous and defective molecular structure of nanocarbons can potentially enhance their functionalities for advanced electronic applications by providing a large working volume, rapid transport of electrolytes and reactants, and active sites for electrochemical reactions. Here, we report successful fabrication of 3D porous and defective nanocarbons by direct pyrolysis of crab shell-derived chitin nanofiber paper. The pyrolyzed chitin nanofiber paper has tunable electrical resistivity (1013 to 10−2 Ω cm), 3D porous structures with layered nanofiber networks, and defective nitrogen-doped carbon molecular structures. The pyrolyzed chitin nanofiber paper shows good performance as a photosensor and an energy-storage supercapacitor electrode, proving that the tailored 3D porous and defective carbon structures play key roles in the drastic improvement of the performance. This pioneering approach can be used for fabrication of chitin nanofiber-derived nanocarbons with excellent multiple functions for future sustainable electronics. [ABSTRACT FROM AUTHOR]

Hydrogel-based flexible electronics have received increasing attention owing to the requirement in a variety of applications. However, the design and development of underwater and self-adaptive high-temperature strain sensors remain a significant challenge because of the swelling and dehydration of hydrogels in aquatic environments and extreme climate conditions. Herein, a versatile gel with superior self-adhesiveness, long-lasting underwater stability, excellent high-temperature tolerance and long-term non-drying properties is successfully prepared, which can serve as a wearable sensor for precisely and reliably detecting diverse body movements and the direction of human movements in air and aquatic environments. Meanwhile, based on the Morse code expression, the as-fabricated gel sensor can also be utilized as a wearable communication device for delivering various messages to the receiver. Furthermore, a wireless sensor with high-temperature adaptability is constructed, which can transmit in real time the motion signals at high temperature to the specific APP of a smartphone at room temperature via wireless communication. This strategy provides a new perspective and great convenience for motion monitoring under harsh conditions. In particular, the as-prepared gel demonstrates an obvious transparency-shifting behavior in different polar solvents, thus inspiring us to engineer it as a novel water-writing paper for achieving repeatable "writing–erasing" applications. [ABSTRACT FROM AUTHOR]

The integration of SERS-active enhanced agents with the functional supporting substrate of paper to expand the application of SERS technology has attracted much attention. However, it is still highly desired to improve the detection ability of paper-based SERS substrates for complex mixtures to extend the application of SERS further in real-word scenarios. Herein, we assemble raspberry-like bimetallic Au@AgNP nanostructures with multiple hotspots on an arrow-shaped paper strip to detect complex samples sensitively. Raspberry-like bimetallic nanoparticles show more sensitive and stable SERS performance than spherical AgNPs, which improves the practicability of SERS-based paper substrates in realistic situations. The intervention of charge gradients as well as designing of arrow-shaped non-interference tips yields the substrate-integrated shunt and preconcentration abilities for mixture samples. Thus, this SERS-based paper substrate may provide a promising way for the determination of complex samples in food security and environmental protection. Our work will have a positive impact in pushing forward the application process of SERS technology in real-word scenarios. [ABSTRACT FROM AUTHOR]

The remarkable properties of layered semiconductor nanosheets (LSNs), such as scalable production, bandgap tunability and mechanical flexibility, have promoted them as promising building blocks for nanoelectronics and bioelectronics. However, it is still a challenge to efficiently control the charge transport in LSNs. Here, we demonstrate a novel LSN field-effect transistor (FET) using ionic paper (i-paper) as a solid-like gate dielectric, achieving a highly efficient ionic control of hole and electron transport in MoS2 and WSe2 LSNs, respectively. The i-paper contains a three-dimensional (3D) nanopore structure that allows ionic liquids (ILs) to infiltrate the LSN surface, providing a very large ion/carrier interfacial region as well as an efficient ion transport channel. We achieve an ultra-high current on–off ratio of over 105 for both p-type and n-type i-paper gated LSN FETs. By directly attaching one common i-paper to both n-type and p-type LSN layers, a flexible LSN-based inverter circuit with a gain of ∼3 is realized. Moreover, high-performance i-paper gated LSN FETs are capable of detecting a temperature change as low as 0.02 K. Our results can hold great implications for wide applications of i-paper gated LSN FETs in the future. [ABSTRACT FROM AUTHOR]

Photonic paper with dynamically tunable color has been widely investigated due to its excellent ability to change its optical patterns under external variation. Herein, a UV-responsive metal–insulator–metal (MIM) Fabry-Perot cavity is proposed to prepare dynamic photonic paper through introducing disulfide bonds containing polyurethane as an insulating layer. The as-prepared MIM cavity based photonic paper shows dynamically tunable color variation in almost the whole visible gamut under different UV-irradiation durations. In addition, by simply adjusting the UV-irradiation duration at each point with the aid of a photomask, multicolor patterns could be "written" onto the as-prepared MIM photonic paper. What's more, thanks to the dynamic feature of the disulfide bond, the color patterns on the photonic paper could also be "erased" by thermal treatment, making the photonic paper "rewritable". Together with all these features, the proposed UV-responsive MIM photonic paper would exhibit great potential for application in information anticounterfeiting, dynamic color display devices and environment-friendly inkless color printing. [ABSTRACT FROM AUTHOR]

Paper-based flexible sensors have attracted much attention due to their abundant resource, low cost and good degradability in the natural environment leaving no electronic waste (e-waste). However, the mechanical properties of paper still need to be strengthened and the output stability may be impacted by water or high humidity because of the hydrophilicity of cellulose fibers. In order to solve these problems, for the first time, a paper-based flexible sensor with available running data under water without encapsulation was fabricated using softwood cellulose fibers and graphite nanoplates through a papermaking technique in this work. The cellulose nanofibers (CNFs) were added to reinforce the paper and the alkyl ketene dimer (AKD) emulsion was coated on the paper to endow it with super-hydrophobicity. The sensor can be used for both strain and pressure detection. As a strain sensor, the gauge factor (GF) was 18.99 and the response time was 0.3 s. It can be used to monitor human motions such as the bending of fingers, the wrist, and elbow. Interestingly, it was proven to be able to monitor finger bending at high humidity and under water due to its super-hydrophobicity. As a pressure sensor, it exhibited sensitivity S1 = 0.019 kPa−1 in the range of 0 to 316.5 kPa, and S2 = 0.01 kPa−1 in the range of 316.5 to 1421 kPa, with the response time of 0.3 s. The detecting range is much wider than that of reported sustainable flexible pressure sensors. Furthermore, this sensor can be easily disposed of by burning, thus avoiding the production of e-waste. This multifunctional flexible paper-based sensor may find potential in sport and health monitoring, soft robotics and human–machine interfaces. [ABSTRACT FROM AUTHOR]

Stimuli-responsive fluorescent materials are ideal materials for paper anti-counterfeiting applications. However, the single responsiveness and the lacking of dynamics present the risk of being deciphered. Herein, we designed a series of cyanostilbene derivatives (ACNs) with fluorescence responses to acid or base. ACN1 with pyridine and hydroxyl groups exhibit dually responsive fluorescence "ON" in the solid state due to the ionization-enhanced intramolecular charge transfer (ICT) effect. Other ACNs with either pyridine or hydroxyl unit show only single responsiveness. Fluorescence papers (FPs) prepared by a simple dipping into the solutions of ACNs maintain the responsive fluorescence performance. FP1H with high ACN1 content exhibits time-dependent dynamic fluorescent colour changes by hydrogen chloride (HCl) vapour fumigation. The applications of paper anti-counterfeiting and information encryption are developed by combining ACN1 with other single-responsive ACNs. Moreover, a four-dimensional (4D) code with time-dependent information changes is designed. Our work provides new materials for the field of paper fluorescent anti-counterfeiting encryption. [ABSTRACT FROM AUTHOR]

A newly proposed idea for the fabrication of white magnetic paper is presented. These papers are fabricated from a layered composite of bacterial cellulose (BC) sheets. Magnetic BC sheets are prepared by the incorporation of CoFe2O4 nanoparticles (NPs) in the BC structure (MBC). White BC sheets were formed by the impregnation of ZnO NPs in the BC nanofibrils (ZBC), and then forming a ZBC/MBC/ZBC sandwich structure. This structure was then hot-pressed to obtain white magnetic paper. The fabricated magnetic BC paper exhibits a ‘whiteness’ of over 80%, with a high reflectance of over 70% in the visible spectral range. XRD and SEM analysis confirmed the presence of the BC, CoFe2O4 and ZnO phases in the white magnetic paper. The whiteness of the paper is improved further with a higher concentration of ZnO NPs, but at the cost of a reduction in the mechanical properties. Magnetic hysteresis was observed in the fabricated white magnetic paper with a saturation magnetization of ∼20 emu g−1, comparable to the literature values for black magnetic papers. The white magnetic paper was demonstrated to exhibit flexibility and foldability just like regular paper sheets but can also be distinguished by subjecting it to an external magnetic field. This gives potential for its use as security paper or in anti-counterfeiting applications. [ABSTRACT FROM AUTHOR]

Wearable displays with aesthetic design, durability, and washability are highly desired for communication and information gathering wherever and at any time. However, daily wear and washing might damage the characteristics of wearable displays with flexible plastic or extra elastomer substrate, and long-time repeated actuation could also lead to electric fatigue in the display. Here, we proposed a machine-washable, tailorable, and comfortable wearable textile-based electrophoretic electronic paper display (EPD) by encapsulating the electrophoretic ink microcapsules and hot pressing EPD into the daily textile. The gadget exhibited a contrast ratio of 13 and good stability after repeated harsh deformation (e.g., soaking, needling, tailoring, or machine washing). The optimal contrast ratio that benefited from the selected high- κ elastomer waterborne polyurethane (WPU) was achieved in human safety voltage. To demonstrate its potential application, the EPD prototypes of a patterned static display T-shirt and a lightweight dynamic display wristband watch were fabricated by screen printing and laser engraving. The as-fabricated textile-based EPDs with features, including simple fabrication with aesthetic design, excellent waterproofness, low energy consumption, and stretchability, provide important guidance for human and machine interaction for realizing truly wearable displays (i.e., wearing displays). [ABSTRACT FROM AUTHOR]

Analyzing the components and contents of environmental gases is of great importance for industrial production, human health, and environmental safety. Carbon dioxide (CO2) has drawn great concern for its adverse effects on climate change and physical health. Simple, in situ, and selective methods for CO2 detection are thus highly demanded. This work presents a versatile and easily fabricated paper sensor for the selective detection of ambient CO2. The sensor consists of two components with a fluorescent molecule ANT-PPh3 as the sensing element and an ionic liquid [DBUH]+[Im]− for the absorption of CO2. Based on the photo-induced electron transfer (PET) between ANT-PPh3 and [DBUH]+[Im]−, the sensor exhibited fluorescence enhancement in the presence of CO2, and the response process is reversible. The sensor exhibits improved selectivity for CO2 over SO2 and NO2 compared with most reported works, with good stability and fast response to human breath. Without complex instrumentation and gas pre-collection processes, the early notification of high indoor CO2 concentrations was realized using this sensor. Taking advantage of its intuitive fluorescence changes, specific responsiveness, and convenience, we believe our designed CO2 sensor could be applied practically in monitoring and indicating high indoor CO2 concentrations in living scenarios. [ABSTRACT FROM AUTHOR]

Transportation and storage of primary agricultural products, processed foods, and special items should be carried out in accordance with the requirements of cold chain transport to ensure that they are maintained within the appropriate low temperature range. Time-temperature indicators (TTIs) have proven to be an effective tool for monitoring food temperature history during the cold chain transport. Herein, a disposable paper nano-temperature sensor for color-changing temperature indicators was developed based on the strong linear photoluminescence dependence of cesium–lead–bromide perovskite nanocrystals (CsPbBr3 NCs), where the anion-exchange reaction between Br− and I− can be influenced by the melting temperature from different compositions of n-hexane/1-octadecene (ODE) mixtures. The actual temperature of a mixed solvent exceeds the specified threshold temperature (Tt), causing the mixed solvent containing iodide ions to melt, flow and impregnate the film, and thus resulting in an irreversible change in the fluorescence (FL) emission wavelength of the CsPbBr3 NCs. The FL emission wavelength is red-shifted from the original 517 nm to 650 nm, showing a large Stokes shift of more than 130 nm, which can be directly observed under a UV lamp from green to yellow, orange, and red. Accordingly, this disposable paper nano-temperature sensor with multiple color change patterns and multiple threshold temperatures of −68 °C to +4 °C is effective, portable, and stable, which provides new insights into efficient temperature monitoring for cold chain transport. [ABSTRACT FROM AUTHOR]

The development of viologen-based photochromic composite materials with a fast response to ultraviolet light has become a major research focus. In this paper, we fabricated viologen-based composite films with excellent durability and rapid photochromic performance by the solution casting method. The films changed color within one second when exposed to ultraviolet light (3 W, 365 nm). This was because ZnO NPs photogenerated electrons that enhanced the photoreduction of viologens with matched energy bands. The decoloration process of the films could be regulated by different moisture levels while keeping their photochromic properties unaffected. Moreover, the films exhibited less than 15% change in absorbance over 20 repeated coloring and fading cycles. Therefore, the excellent photoresponsiveness, repeatability and environmental friendliness of the films provide them potential for applications in areas such as rewritable paper, solar UV detection, smart windows and anti-counterfeiting. [ABSTRACT FROM AUTHOR]

Organophosphorous pesticides pose a significant threat to public health, making its detection critical. Herein, a new fluorescent metal–organic framework, Eu-NDC, was synthesized, which possessed a 3D supramolecular structure assembled through π⋯π interactions between the naphthalene rings in its adjacent coordination-bonded layers. Then, four different products of the Eu-NDC MOF (Eu-NDC-1/2/3/4) with different morphologies were further obtained by altering the ratio of the raw materials. Among them, the fluorescence properties and BET surface area of the micro-nanoscale Eu-NDC-3 were significantly enhanced, making it the most favorable for detection. Eu-NDC-3 as a turn-off fluorescence probe for methyl paraoxon (DMNP) exhibited excellent sensitivity and selectivity, anti-interference and durability. Thus, considering these features, an intelligent logic gate was designed, showing great promise for application in smart sensing. Furthermore, an Eu-NDC-3-loaded electrospun fibrous strip was fabricated as a portable and in situ platform for visual DMNP assay. [ABSTRACT FROM AUTHOR]

Humidity sensing plays an important role in diverse applications in the fields of agriculture, healthcare, skincare, and environmental monitoring. With the advent of the "trillion sensor" society, there is a growing demand for humidity sensors that can be made from abundant and renewable resources. Cellulose, the most abundant and renewable bioresource on Earth, acts as a humidity-sensing material because of its hydrophilic nature. However, non-renewable noble metal electrodes are still indispensable because good electrical conductivity and moisture stability are necessary for reliably detecting electrical signals from cellulose-based humidity-sensing materials. Herein, we demonstrate the direct CO2-laser writing of electrodes onto TEMPO-oxidized cellulose paper to realize an all-cellulose-derived humidity sensor. The TEMPO-oxidized cellulose paper with sodium carboxylate groups provides a satisfactory humidity-sensing performance and is converted to conductive and moisture-stable electrodes directly via laser-induced carbonization. The resulting all-cellulose-derived humidity sensor demonstrates high sensitivity and linearity over a wide range of relative humidity (11–98%), thereby providing broad applicability. The sensor can be used for the positional localization of moist objects and for monitoring plant transpiration and human-body sweating. These results open the door for renewable and sustainable humidity sensors. [ABSTRACT FROM AUTHOR]

Paper-based sensing technology has attracted much attention due to its light weight, low cost, ease of fabrication, and many other advantages. Here we combine paper-based sensing technology with a direct laser writing method to design and fabricate a simple and wearable healthcare sensor based on polyimide (PI)/paper bilayer structure. With assistance of infrared spectroscopy, thermogravimetric analysis, Raman spectroscopy, scanning electron microscopy and coupled electrical–mechanical testing, the effect of material processing temperature on the sensing characteristics of the PI/paper bilayer film was studied. The PI/paper bilayer film-based sensors have been successfully demonstrated for their use in monitoring pulsing and respiration activities, and in working as dual sensors for simultaneously detecting force and humidity stimuli. The differential response of PI and paper to different chemical and physical stimuli would make the PI/paper bilayer film a versatile platform for developing multi-functional and multi-modal sensors. [ABSTRACT FROM AUTHOR]

Flexible wearable electromagnetic interference (EMI) shielding materials have attracted great attention with the development of portable electronic devices, and paper based EMI shielding materials turn to be ideal candidates due to their flexibility, biodegradability and low cost. In this study, conductive MXene nanosheet decorated paper was developed through a simple dip-coating technique, where the MXene nanosheets can be strongly adhered onto the surface of cellulose fiber to construct an effective conductive network. Meanwhile, a low surface energy and micro-nano-structured 1H, 1H, 2H, 2H perfluorodecanethiol (PFDT)/carbon black (CB) layer was further introduced onto the surface to construct a superhydrophobic surface, avoiding the hygroexpansion of paper in water or moisture environments effectively. As a result, the prepared PFDT/CB/MXene@Paper exhibits reflection dominant EMI shielding performance, and a specific SE value of up to 3339.6 dB cm-2 g-1 was achieved. Importantly, the EMI shielding performance can be well maintained towards cyclic bending and in various acid, alkali, salt, and UV environments, which enhance the applicability of paper based functional materials significantly. Finally, its high conductivity also endows it with good Joule heating performance, improving the wearing comfort when used as a wearable EMI shielding material. This study will undoubtedly provide a high-efficiency design strategy for fabricating high-performance paper based EMI shielding materials. [ABSTRACT FROM AUTHOR]

In recent years, paper-based bending strain (PBS) sensors for bending deformation and angle detections have attracted much attention in flexible electronics. However, PBS sensors based on a surface microcrack sensing mechanism have drawbacks of small response and poor water resistance. Herein, we construct a cross-section interface between two conductive papers to form a PBS sensor that can be encapsulated using adhesive tape. Benefiting from the cross-section interface response mechanism of the PBS sensor, it can be directly encapsulated with polyimide tape without worrying about the destruction of the paper surface microstructure. Therefore, the PBS sensor shows excellent water resistance. Meanwhile, the proposed PBS sensor has good bending strain properties. Taking the bending angle of 35.7° as an example, the PBS sensor has a very high response (36.5, relative current ratio after and before bending), good repeatability (2000 times) and acceptable response/recovery times (0.34/0.35 s). In addition, the potential applications of the PBS sensor in the human body and security doors are confirmed. This work not only proposes a novel, high-response, waterproof, and low-cost PBS sensor, but also provides new strategies for the development of bending strain sensors from cross-section interfaces with surface encapsulation. [ABSTRACT FROM AUTHOR]

Organic transistors are being developed for a variety of flexible electronics applications. They are usually fabricated on polymeric substrates, but considering the significant negative impact of plastic waste on the global environment and taking into account the many desirable properties of paper, there have also been efforts to use paper as a substrate for organic transistors. In this review we provide a brief overview of these efforts. [ABSTRACT FROM AUTHOR]

Flexible polymer-based dielectric materials that are used to store dielectric energy have widely been used in modern electronics and electric power systems, due to their relatively high energy density, light weight, low cost, etc. However, owing to the growing global environmental issues and a rapid consumption of nonrenewable polymer resources, there exists a strong desire to fabricate flexible dielectric materials using biodegradable materials. Here, we report on flexible dielectric papers based on biodegradable cellulose nanofibers (CNFs) and carbon nanotubes (CNTs) for dielectric energy storage. Highly ordered, homogeneous CNF/CNT papers have been fabricated using a facile vacuum-assisted self-assembly technique. The obtained paper possesses a high dielectric constant of 3198 at 1.0 kHz, thus leading to enhanced dielectric energy storage capability (0.81 ± 0.1 J cm−3), which is attributed to the presence of a low loading of CNTs (4.5 wt%). Moreover, the CNF/CNT papers are mechanically flexible and show improved mechanical strength. These findings enable feasible fabrication of high-performance flexible dielectric materials using ecofriendly materials. [ABSTRACT FROM AUTHOR]

This report describes the fabrication of hybrid paper made from wood fibers to which barium titanate (BaTiO3) nanoparticles were anchored. This hybrid paper is mechanically as strong as a commercial printing paper (breaking strength = 1.55 N mm−2), it is flexible and possesses a large piezoelectric coefficient (d33 = 37–45.7 ± 4.2 pC N−1). Using this paper, we demonstrate an accelerometer, with a sensitivity of 82.45 pC g−1. The accelerometer is formed by laminating the piezoelectric paper with electrodes made from conductive ink and a seismic mass is bonded to this assembly. According to our model, the dynamic range, 1–70 Hz, of the sensor can be increased by reducing the seismic mass at the expense of a lower sensitivity. [ABSTRACT FROM AUTHOR]

The document is a contents list for the Journal of Materials Chemistry C. It includes reviews, new journal information, and a list of papers published in the issue. The topics covered in the papers range from nanomaterials for smartphone sensors to quantum dot light-emitting diodes. The journal aims to connect the world with the chemical sciences and is dedicated to sustainable chemistry and new solutions. [Extracted from the article]

Paper substrate based organic field-effect transistor (OFET) nonvolatile memories (NVMs) not only exhibit many advantages such as being low-cost, biodegradable and renewable, but also hold promise for novel application as single-use and disposable NVMs for storing personal health statuses in daily life and providing good privacy protection by offering easy physical destruction in the technology of the internet of everything. This study demonstrates a facile method to realize a multi-bit OFET-nonvolatile memory (NVM) on an ordinary commercial paper substrate by designing and fabricating a multilayer ferroelectric gate dielectric, by which both the mobility and controllability of the remnant polarization depending on the gate voltages are greatly improved. The multi-bit OFET-NVMs on a paper substrate show excellent performances with a high mobility up to 0.92 cm−2 V−1 s−1, a distinct four-level reading IDS with a large memory margin of about one order of magnitude was achieved at low multi-level programming/erasing voltages (<40 V), and a reliable four-level switching endurance over 100 cycles and stable four-level data retention over 20 000 s was demonstrated. Additionally, the paper-based multi-bit OFET-NVMs exhibited a good mechanical bending durability and environmental stability against humidity, temperature, and air, indicating their potential application in flexible electronics. To the best of our knowledge, this is the first report of multi-bit OFET-NVMs on paper substrates. [ABSTRACT FROM AUTHOR]

Insights into advances in portable and flexible electronic devices can be gained from the integration of magnetic nanoparticles with light weight and flexible conductive supports, especially in cases where the thickness of the material is challenging for future electromagnetic interference shielding applications. Here we report the fabrication of flexible shielding materials made up of Fe3O4 nanoparticles incorporated mesocarbon microbeads and multiwalled carbon nanotubes (MCMBs/MWCNTs) composite paper for efficient electromagnetic interference (EMI) shielding in the X-band frequency region (8.2–12.4 GHz). The incorporation of Fe3O4 nanoparticles in the MCMBs/MWCNTs composite paper significantly increases its interfacial polarization and anisotropy energy, which leads to an excellent absorption dominated EMI shielding effectiveness (SE) of −80 dB at 0.5 mm thickness. The composite paper also exhibits improved magnetic properties coupled with enhanced dielectric properties that increase with increasing concentration of Fe3O4 nanoparticles. Our measurements have provided a regime for designing conductive networks with advantages of light weight and flexibility, with promising EMI shielding applications. [ABSTRACT FROM AUTHOR]

Recently, visible-light-responsive rewritable papers (VLRPs) have attracted significant attention because of the superior penetration and less damage of visible light as compared to the case of ultraviolet light. However, to date, the most classic and frequently usable high-performance black VLRPs have not been realized. Herein, a new black VLRP with high purity and contrast was fabricated. The as-prepared black VLRP shows excellent reversibility (>60 cycles) and can be simply and automatically printed using commercial visible laser printing technology. This work proposed a new strategy for the development of high-performance switchable black displays. [ABSTRACT FROM AUTHOR]

The use of functional nanomaterials and their combination with organic polymers leads to the formation of advanced composites and hybrid inorganic–organic systems having unique properties. The use of such materials as anti-counterfeiting agents (invisible under ambient conditions) is crucial for modern security systems and for further identification of labelled items and documents in various industrial applications. Here, the fabrication of functional paper by in situ incorporation of luminescent cellulose fibres into its structure, during the formation of paper pulp, is shown. In order to produce luminescent fibres, an in situ modification is made during the spinning process, using lanthanide-doped upconverting nanoparticles (SrF2:Yb3+,Er3+). At first glance (in daylight), the functionalized paper cannot be distinguished from its unmodified form. However, when exposed to invisible near-infrared laser light (975 nm), bright green illumination appears. The modified paper preserves good mechanical durability, which is important for its potential for further processing in documents and other commercially available forms. Protecting documents and various materials with this kind of paper may open new horizons in materials engineering, forensics, and other industrial applications. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H2O2) is a typical reactive peroxide that is widely used in food preservation but may cause serious harm to human health. Thus, a simple, efficient and accurate method for H2O2 assay is essential. In this work, a dual Eu-MOFs-based ratiometric fluorescence sensor, a logic gate-based advanced analytical method, and a dual MOFs-loaded paper microchip for visual H2O2 assay were constructed. The H2O2 sensor was response-sensitive (limit of detection: 0.14 μM) and linearly responsive in the concentration range of 0.001–1 mM (r > 0.99). Then, an advanced AND gate logic device was established to monitor H2O2 concentration. Moreover, the paper-based microchip realized the point-of-care visual H2O2 assay via ratiometric chromaticity assisted by a portable smartphone-based visual assay device. The microchip consumes only 5 μL of sample and demonstrates long-term stability for over 30 days along with response-sensitivity. Both the MOF dispersion-based ratiometric fluorescence sensor and the paper microchip realized an accurate and precise assay of H2O2 (the recovery was 88.2–105.5% and RSD < 9.3%). To the best of our knowledge, this is the first report of a dual MOFs-based ratiometric fluorescent H2O2 sensor, an advanced logic gate-based analytical method, and a paper-based microchip for visual point-of-care H2O2 assay. [ABSTRACT FROM AUTHOR]

Super-flexible, electrically and thermally conductive graphene-based papers are in great demand in the fields of electronics and supercapacitors. However, the applications of graphene-based papers are limited either by their brittleness, small scale, or by their unsatisfactory thermal conductivity. Conventionally, such papers are fabricated by vacuum-assisted filtration, direct evaporation, electrospray coating, or wet spinning. Here we propose a novel strategy, namely, direct densification of reduced graphene oxide foam, to fabricate large-scale multifunctional graphene papers. The graphene paper density could be adjusted by applying different loads. The densities of the graphene papers varied from 0.32 g cm−3 to 1.85 g cm−3. The thermal conductivity, tensile stress, electrical conductivity and electromagnetic interface shielding effectiveness increased with an increase in the density of the graphene paper. When the density of the graphene paper reached 1.85 g cm−3, the tensile stress was up to 50.4 MPa with strain of 4%, the thermal conductivity was 1103 W m−1 K−1 at room temperature and there was high electrical conductivity of 1.1 × 105 S m−1, as well as an electromagnetic interference (EMI) shielding effectiveness of 77.2 dB. Our new strategy is very promising in terms of controlling the thickness, density, and size of graphene paper. Our graphene paper has very high potential for applications. [ABSTRACT FROM AUTHOR]

Scalable and low cost fabrication of light weight flexible electromagnetic (EM) wave absorbers is highly desirable for the rapid development of wearable electronic devices. A simple method has been developed involving incorporation of rationally designed FeNi3/Mo2C into cellulose fibers in the formation of thin and flexible absorbing papers with tunable electromagnetic parameters. High-performance absorption has been achieved with the minimum reflection loss (RL) reaching −51.50 dB at 13.7 GHz and an effective absorption bandwidth of 5.1 GHz with a thickness of 2.0 mm due to the synergic effects of dielectric and magnetic loss. For emerging flexible absorbers, accurate electromagnetic measurements by using a conventional coaxial method are challenging without the addition of wax or paraffin as the solidification agent. A stacking and compressing method has been developed to prepare standard-sized core samples for coaxial measurements for which the validity has been confirmed by comparison with the waveguide and arch methods. Consequently, not only a new type of effective EM absorber has been developed and verified by all the available measurement methods, but this simple and scalable method applied to fabricate flexible electronic devices is also extendable for applications in sensing, catalysis and energy storage. [ABSTRACT FROM AUTHOR]

Electronic textiles (E-textiles) have received extensive attention for use in human motion detection, wearable electronics, and artificial intelligence. However, fabrication costs and methodology are still key issues preventing the commercialization of highly sensitive and wearable sensors. Here, simple to prepare low-cost conductive MXene-coated airlaid paper (MXene AP) sensors were fabricated via a dip-coating technique for use as electronic skin. The two-layer MXene AP sensors with a three-dimensional structure display high sensitivity (7.65 kPa−1 at 0–3.3 kPa), a broad sensing range (up to 300 kPa), and a stable response for more than 1000 cycles, presenting good sensitivity, repeatability, and durability, and their mechanism was investigated. Furthermore, origami technology can be used to fold MXene AP into an arbitrary shape with good sensing performance, and multistate conformational changes and simulated human touch can also be detected using the resultant three-dimensional (3D) MXene AP sensors. The wearable MXene AP sensors can be used to monitor human body motion and to collect human physical signals sensitively and accurately in the form of electronic skin. These strategies of folding and layering textile-decorated conductive nanomaterials provide a reference for next-generation textile-based wearable electronics and electronic skin. [ABSTRACT FROM AUTHOR]

Inkjet printing of functional frequency selective surfaces (FSS) and radio frequency identification (RFID) tags on commercial paper substrates using silver nanoparticle inks sintered using low temperature thermal, plasma and photonic techniques is reported. Printed and sintered FSS devices demonstrate performances which achieve wireless communication requirements having a forward transmission scattering parameter, S21, depth greater than −20 dB at 13 GHz. Printed and plasma sintered RFID tags on transfer paper, which are capable of being mounted on skin, improved read distances compared to previously reported single layer transfer RFID tags fabricated by conventional thermal sintering. [ABSTRACT FROM AUTHOR]

Paper-based substrates integrated with plasmonic nanostructures and combined with surface enhanced Raman spectroscopy (SERS) offer a flexible and lightweight platform for the ultrasensitive optical detection of analytes on any surface. Here, we incorporated multibranched gold nanoantennas (MGNs) on inexpensive filter paper to design MGN-paper dipsticks and swabs for SERS mediated sensing of chemicals, proteins, and pesticides adsorbed on fruits. MGNs are anisotropic nanostructures consisting of a core which serves as the antenna and protrusions that serve as emitters redistributing incident light. The nanoantenna effect gives rise to intense electromagnetic fields on the tips of the protrusions that enabled a detection of 100 pM of 1,4-benzenedithiol and 100 fM of human serum albumin labeled with indocyanine green with the MGN-paper dipsticks. Further, MGN-paper swabs enabled the detection of 62.5 pg of solid state 4-aminothiophenol on a planar surface, and 26.3 μg of methyl parathion adsorbed on an apple. Finite difference time domain simulations demonstrated that the nanoantenna effect can be systematically modulated by altering the core-to-protrusion ratio to generate a ∼65× enhancement in the electromagnetic fields localized on the protrusions which may ultimately result in sub-femtomolar to zeptomolar detection sensitivities. [ABSTRACT FROM AUTHOR]

Measurement of friction force is important for safety, security, and health. Excessive friction force causes degradation of materials and biological bodies. For example, tooth enamel and gums are damaged by strong toothbrushing force. However, friction force is not easily measured by conventional materials and devices. Here, we proposed design strategies of a paper-based device for measurement of friction force. Toothbrushing force, a model of weak friction force, is the measurement target in the present work. Soft layered composites of polydiacetylene (PDA) and interlayer guest macromolecules were designed and synthesized to achieve a visible color change in response to weak friction force. A data-scientific approach assisted in the selection of the interlayer guest molecule to control the stimuli responsivity of the layered PDA. The guest polyethyleneimine (PEI) formed soft layered composites exhibiting a color change in response to weak friction force. The paper-based device of the layered PDA/PEI composite showed a gradual color change from blue to red in response to the strength and number of the applied friction force. As a model case, toothbrushing force was measured using the paper-based device. The present work shows new design strategies of molecules and materials toward measurement of a wide variety of friction forces. [ABSTRACT FROM AUTHOR]

The document is a contents list for the Journal of Materials Chemistry C. It includes reviews, papers, and communications on various topics related to materials for optical, magnetic, and electronic devices. The journal is published by The Royal Society of Chemistry and aims to connect the world with the chemical sciences. The contents list provides a range of research articles on topics such as organic thin-film transistor sensors, quantum dots, conducting polymer films, perovskite light-emitting diodes, and more. [Extracted from the article]

The document is a contents list for the Journal of Materials Chemistry C. It includes a range of papers and communications on topics such as solar cells, photodetectors, crystal growth, and fluorescence detection. The journal aims to connect the global chemistry community and invest its profits back into the field. The document provides a comprehensive overview of the articles published in the journal's latest issue. [Extracted from the article]

This document is a contents list for the Journal of Materials Chemistry C, published by the Royal Society of Chemistry. It provides a list of articles and papers published in the journal in 2024, covering a wide range of topics related to materials for optical, magnetic, and electronic devices. The document includes titles, authors, and page numbers for each paper. Additionally, there are two corrections listed at the end of the document. [Extracted from the article]

A novel generation of flexible opto-electronic smart applications is now emerging, incorporating photovoltaic and sensing devices driven by the desire to extend and integrate such technologies into a broad range of low cost and disposable consumer products of our everyday life and as a tool to bring together the digital and physical worlds. Several flexible polymeric materials are now under investigation to be used as mechanical supports for such applications. Among them, cellulose, the most abundant organic polymer on the Earth, commonly used in the form of paper, has attracted much research interest due to the advantages of being recyclable, flexible, lightweight, biocompatible and extremely low-cost, when compared to other materials. Cellulose substrates can be found in many forms, from the traditional micro-cellulose paper used for writing, printing and food/beverage packaging (e.g. liquid packaging cardboard), to the nano-cellulose paper which has distinct structural, optical, thermal and mechanical properties that can be tailored to its end use. The present article reviews the state-of-the-art related to the integration and optimization of photonic structures and light harvesting technologies on paper-based platforms, for applications such as Surface Enhanced Raman Scattering (SERS), supporting remarkable 107 signal enhancement, and photovoltaic solar cells reaching ∼5% efficiency, for power supply in standalone applications. Such paper-supported technologies are now possible due to innovative coatings that functionalize the paper surfaces, together with advanced light management solutions (e.g. wave-optical light trapping structures and NIR-to-visible up-converters). These breakthroughs open the way for an innovative class of disposable opto-electronic products that can find widespread use and bring important added value to existing commercial products. By making these devices ubiquitous, flexible and conformable to any object or surface, will also allow them to become part of the core of the Internet of Things (IoT) revolution, which demands systems’ mobility and self-powering functionalities to satisfy the requirements of comfort and healthcare of the users. [ABSTRACT FROM AUTHOR]

Carbamazepine (CBZ) is usually used as a marker to reflect human health in biofluids and anthropogenic pollution in the aqueous system. However, few chemosensors sensitive enough to detect the allowable concentration of CBZ are available in practice. For this purpose, "luminescence-colour-changing sensing" test papers have been designed and prepared, exhibiting nanomolar limits of detection toward CBZ in water, urine, and serum. The systematic anchoring of yellow-light-emitting MOF-76 (Eu0.05Tb0.95) and blue-light-emitting carbon dots (CDs) on a polyvinyl alcohol (PVA) substrate, a white-light-emitting film (0.012CD/Eu0.05Tb0.95BTC/PVA) has been obtained by precise tuning of the component ratios. Through hydrogen bonding interactions, the luminophores (CD and Eu0.05Tb0.95BTC) show a uniform dispersibility on the PVA substrate, as well as advanced thermal, mechanical, environmental, and biochemical stability regarding their structure and photoluminescence. Benefiting from these beneficial photophysical properties and a powerful adsorption capacity, the 0.012CD/Eu0.05Tb0.95BTC/PVA film displays exceptional sensitivity toward nanomolar-level CBZ in water and biofluids (urine and serum), via a luminescence colour change from white to blue. The advances in stability, sensitivity, selectivity, and recyclability of the sensor reveal the promising potential of this portable, fast and accurate sensor in practice. [ABSTRACT FROM AUTHOR]

Gallium oxide (Ga2O3) has been extensively studied recently because it is a natural candidate material for next generation solar-blind deep ultraviolet photodetectors (PDs). In this study, three dimensional (3D) amorphous Ga2O3 films (a-Ga2O3) were grown on carbon fibre paper (CFP) using a facile one-pot sputtering method. The prepared a-Ga2O3/CFP core–shell composites were used as photoanode materials for a new type of solar-blind photoelectrochemical (PEC)-type photodetector. By constructing a solid/liquid heterojunction, the resulting built-in electric field can separate electron–hole pairs effectively, facilitating a self-powering ability in this PEC-type photodetector. The device exhibited a maximum responsivity of approximately 12.90 mA W−1 and a rapid photoresponse time of around 0.15/0.13 s without external bias potential. Additionally, the PEC-type photodetector demonstrated outstanding stability after significant usage over a one-year period. The excellent performance of the fabricated a-Ga2O3/CFP core–shell photoanode, for self-powered PEC-type photodetectors, is extremely promising in the field of solar-blind photoelectric detection. [ABSTRACT FROM AUTHOR]

Proton gradient reactions are common, but those with inverse proton gradients are rare. Inspired by the phenomenon that stomach can release acid with microenvironment changes, an inverse proton gradient process along with a ring-closing of the precursors of oxazolidine molecular switches (i.e., ROF+X−s) was achieved within specific microenvironments both in solution and on solid substrate. Nucleophilicity and concentration of solution were found playing important roles in this process. Furthermore, benefits from this ring-closing process arose from inverse proton gradient, a potential application of ROF+X−s replacing their akalization products―ring-closed forms (RCFs) of oxazolidines in water-jet rewritable paper (WJRP) was developed. Influence of dissolving solvent and drying temperature on hydrochromic performances of ROF+X− based WJRP were inspected and compared to its corresponding RCF based WJRP. Results indicate that the former outperforms the latter in color depth, coloration speed and retention time. The water-jet prints on ROF+X− based WJRP exert excellent legibility, resolution, uniformity, and repeatability. This research achievement will not only promote the industrialization of oxazolidines derivatives based WJRP by greatly reducing production costs from a perspective of synthetic industrialization, but may also provide a reference for better understanding of similar microenvironment-induced phenomena of inverse proton gradient in complex biosystems. [ABSTRACT FROM AUTHOR]

The document is a contents list for the latest issue of the Journal of Materials Chemistry C, published by The Royal Society of Chemistry. It features articles and papers on various topics, including functional framework materials, organic field-effect transistors, and short peptide hydrogels. The journal aims to connect the world with the chemical sciences. Additionally, the document includes a journal article from The Royal Society of Chemistry in 2024, which investigates the stoichiometric deviation in a mixed cation, mixed halide lead perovskite thin film and its precursor solution. Another article discusses nanoristors made of molybdenum disulfide that are highly uniform, sub-500-millivolt, large-scale, and robust. This article provides detailed information on these topics and is a valuable resource for researchers in the field. [Extracted from the article]

The document is a contents list for the Journal of Materials Chemistry C. It includes a range of papers and reviews on topics such as nanomaterial-based probes for iodide sensing, organic photodiodes, metal-organic frameworks, lithium-ion batteries, and perovskite solar cells. The journal aims to connect the world with the chemical sciences and is published by The Royal Society of Chemistry. The document also mentions approved training courses offered by the Royal Society of Chemistry for professional development. [Extracted from the article]

The Journal of Materials Chemistry C, published by the Royal Society of Chemistry, contains a variety of research papers on topics such as metal-organic framework thin films, perovskite solar cells, energy harvesting devices, electroluminescence, and photocatalytic hydrogen production. The article titled "Hampel and E. M. M. Ibrahim" focuses on materials chemistry and presents the research conducted by Hampel and E. M. M. Ibrahim. The authors discuss their findings and the implications of their research in the field. This article may be useful for library patrons conducting research in materials chemistry. [Extracted from the article]

There are few reports on ZnO being used for flexible substrate based sensors. Most of the studies have documented the use different solvents or inks for the sensor fabrication, which leads to the degradation of the properties of both substrate and sensing materials. This work is the first demonstration of solvent-free direct drawing on a cellulose paper using zinc oxide (ZnO) pencil to fabricate an ultra-violet (UV) light sensor, which was further utilized for photoresponsive uric acid (UA) sensing. The transient analysis was performed for ZnO (with silver (Ag) ohmic contact) and Graphene (Gr)/ZnO (with graphene contact). The recovery time constant observed for Gr/ZnO and ZnO was 8.79 and 18.13 seconds, respectively, which is comparable to that of the photodetector fabricated using the sophisticated cleanroom techniques. The responsivity calculated for ZnO and Gr/ZnO devices under 3.9 mW cm−2 UV light illumination was found to be 4.12 mA W−1 and 6.27 mA W−1, respectively. The excellent UV sensing property of ZnO was further utilized for photoresponsive UA sensing at several concentrations ranging from 100 μM to 450 μM with a sensitivity of 1.99 m μM−1 (R2 = 0.984) and the limit of detection (LOD) of 38.4 μM. In the presence of UA, the photogenerated electrons from ZnO under UV illumination get trapped by oxygen present in UA because of its oxidation in atmospheric air. As the UA concentration increases, the oxidation of UA causes more photogenerated electron traps, which results in the further decrease in the photocurrent. Such a simple and inexpensive way for fabricating ZnO-based devices on paper holds promising applications in the field of flexible and wearable electronic devices, optoelectronic sensors, and medical diagnostic systems etc. [ABSTRACT FROM AUTHOR]

Various carbon nanotube–paper composites (CPCs) have been studied to measure relative humidity. This study presents a tissue paper-based CPC coated with polyacrylic acid (PAA) for sensing humidity and surface moisture. When the CPC is exposed to humidity, its electrical resistance changes due to its electrostatic interaction with water molecules and the swelling of cellulose fibers and PAA. The enhancement of sensor response due to the swelling of CPCs coated with PAA, acid, and Nafion is studied in terms of resistance change. The hysteresis of a CPC sensor response to a cyclic humidity change is characterized for both the CPC region and the interfacial region between carbon nanotubes and a silver electrode. Based on the empirical relationship, the humidity sensor is applied for the measurement of surface moisture in a simulated sweat model. The CPC surface moisture sensor provides a low-cost, highly sensitive, light-weight flexible platform potentially beneficial for health, food, agricultural and environmental applications. [ABSTRACT FROM AUTHOR]

Recently, significant progress has been achieved in paper electronics due to their potential technological applications in rollup displays, wearable devices and smart cards. However, it is still a challenge to efficiently form suitable structured materials on paper substrates due to their porous and rough surface. In this research, ZnO pomegranates composed of 8 nm ZnO nanodots, have been successively fabricated on a pencil drawn graphite-on-paper substrate by an eco-friendly and cost effective solvothermal method. Most significantly, this solution grown photoconductive photodetector shows good device performances with spectrum responsivity to ultraviolet light of 0.06 A W−1 and a quick response time of 4.3 s. Systematic analysis shows that the interface-related energy boundary modulation within ZnO pomegranates may facilitate the separation of photo-induced carriers, eventually resulting in its low dark current and quick response. Meanwhile, this structure designing strategy can be utilized for the future fabrication of high performance paper electronics with other materials. Besides, due to the firm attachment of ZnO pomegranates on the substrate, caused by the introduction of ethanol during the solvothermal growth process and ultrasonic vibration during the formation of the ZnO seed layer, this device is also a highly flexible and rolled-up photodetector with good reversible characteristics and steady performance towards bending deformations and irradiation degradation. [ABSTRACT FROM AUTHOR]