Search

Laser‐induced graphene (LIG) produced by irradiation of paper (paper‐LIG)holds substantial promise for flexible devices. This article presents paper‐LIG humidity and temperature sensors fabricated by single‐step irradiation of common filter paper with a pulsed UV laser (355 nm). The influence of the process parameters on the conversion of cellulose fibers into LIG is discussed based on the resulting morphology, structure, conductivity, and chemical composition, revealing a distinct barrier to transformation and a propagation behavior not seen under CO2 laser irradiation. The obtained material is constituted by a porous, electrically conductive network of fibers. The paper‐LIG relative humidity (RH) and temperature sensors with sensitivities of up to 1.3 × 10−3%RH−1 and ‐ 2.8 × 10−3 °C−1, respectively, are examined in terms of their linearity, reproducibility, and response time. A detailed discussion on the response mechanism is presented in the context of literature, pointing towards the absorption of water molecules in the interlayer spacing of graphene as the main reason for the increase in resistance with RH. Additionally, a contribution from variable range hopping along the ab plane of graphene at high RH is suggested. These results demonstrate the potential of paper‐LIG for low‐cost, sustainable, and environmentally friendly sensing. [ABSTRACT FROM AUTHOR]

Abstract: Paper, one of the oldest materials for storage and exchange of human's information, has been reinvented as a building component of electronic and optoelectronic devices over the past decades with successful demonstration of paper‐based or paper‐using devices. These recent achievements can meet the demand for lightweight, cost‐effective, and/or flexible electronic and optoelectronic devices with advanced functionality and reduced manufacturing costs. This article provides a review of electronic and optoelectronic devices relying on or making use of the unique properties achievable with paper‐based materials. Basic scientific/technical principles, quantitative comparisons of material, electronic and/or optical properties, and benefits for each paper‐based application are given. Application‐specific research challenges, future design considerations, and development directions are also discussed. [ABSTRACT FROM AUTHOR]

Recently, triboelectric nanogenerator (TENG) has aroused considerable interest due to various advantages. Particularly, one benefit which sand out is that the triboelectric pair of TENG is very tolerant to the material composition. Thus, it is possible and significant to develop cost-effective TENG using commercial and inexpensive material. In this work, we present a paper TENG by repeated folding completely using commercially available commodity materials, such as paper, brush pen, Teflon tape, and conductive ink. Paper is used as functionally triboelectric pair and spring-like supporting structure. The stacked paper TENG is fabricated and large enhancement of output performance is observed. The generated electric outputs have been used to directly light-up commercial LEDs. The proposed TENG has demonstrated simplicity and cost-effective, which is suitable for flexible electronics. [ABSTRACT FROM AUTHOR]

Nanostructured composites built with microporous cellulose fibers and carbon nanotubes (CNTs) have potential impacts in the fields of energy storage, sensors, and flexible electronics. Few results have been shown for high mechanoelectrical sensitivity of CNT‐paper composite because of numerous current paths in the network. Here, CNT‐paper‐based nanostructured composite sensors whose sensitivities are generated by controlled tensile fracture of the composite are presented. Under uniaxial load, the cellulose fibers in the paper experience straightening, stiffening, and fracture. The cellulose fibers originally parallel to the tension are fractured while those inclined and perpendicular to the tension are reorganized to form crossbar junctions in the vicinity of a crack. The cross junctions exhibit resistive and capacitive sensitivity to the out‐of‐plane force by the compression of the junctions. Such piezoresistive and piezocapacitive sensitivities are characterized and evaluated for human behavior monitoring. [ABSTRACT FROM AUTHOR]

It is becoming increasingly more important to provide a low-cost point-of-care diagnostic device with the ability to detect and monitor various biological and chemical compounds. Traditional laboratories can be time-consuming and very costly. Through the combination of well-established materials and fabrication methods, it is possible to produce devices that meet the needs of many patients, healthcare and medical professionals, and environmental specialists. Existing research has demonstrated that inkjet-printed and paper-based electrochemical sensors are suitable for this application due to advantages provided by the carefully selected materials and fabrication method. Inkjet printing provides a low cost fabrication method with incredible control over the material deposition process, while paper-based substrates enable pump-free microfluidic devices due to their natural wicking ability. Furthermore, electrochemical sensing is incredibly selective and provides accurate and repeatable quantitative results without expensive measurement equipment. By merging each of these favorable techniques and materials and continuing to innovate, the production of low-cost point-of-care sensors is certainly within reach. [ABSTRACT FROM AUTHOR]

It is becoming increasingly more important to provide a low-cost point-of-care diagnostic device with the ability to detect and monitor various biological and chemical compounds. Traditional laboratories can be time-consuming and very costly. Through the combination of well-established materials and fabrication methods, it is possible to produce devices that meet the needs of many patients, healthcare and medical professionals, and environmental specialists. Existing research has demonstrated that inkjet-printed and paper-based electrochemical sensors are suitable for this application due to advantages provided by the carefully selected materials and fabrication method. Inkjet printing provides a low cost fabrication method with incredible control over the material deposition process, while paper-based substrates enable pump-free microfluidic devices due to their natural wicking ability. Furthermore, electrochemical sensing is incredibly selective and provides accurate and repeatable quantitative results without expensive measurement equipment. By merging each of these favorable techniques and materials and continuing to innovate, the production of low-cost point-of-care sensors is certainly within reach.

Thin inkjet-printed tracks of silver nanoparticles have previously been observed to show a non-reversible decrease in resistance when exposed to a high degree of relative humidity and thus providing sensor functionality with a memory effect. This paper provides a more in-depth explanation of the observed humidity sensor effect that originates from inkjet-printed silver nanoparticle sensors on a paper substrate. It is shown that the geometry of the sensor has a large effect on the sensor's initial resistance, and therefore also on the sensor's resistive dynamic range. The importance of the sensor geometry is believed to be due to the amount of solvent from the ink interacting with the coating of the paper substrate, which in turn enables the diffusion of salts from the paper coating into the ink and thus affecting the silver ink. [ABSTRACT FROM PUBLISHER]

• Fabrication of flexible paper temperature sensors with 658.5 Ω/°C. • Temperature sensitivity of 658.5 Ω/°C, which is 14 times higher than that of sensor with polymer substrate (46.0 Ω/°C), for the temperature range of 30–42 °C. • Reliable process against atmospheric humidity. • Implement a body-attachable temperature patch for wearable thermometer. A highly sensitive, flexible, and wearable paper-based temperature sensor is fabricated using printing paper and poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) solution. It exhibits a negative temperature coefficient and is implemented in a new band-like body-attachable thermometer. Compared to the polymer substrate, the use of hydrophilic and flexible paper substrate facilitates significantly superior sensitivity and simple fabrication. The paper sensor is fabricated by depositing PEDOT:PSS onto the paper with an 80 g base weight for 40 s, which is covered with a 50 μm film to protect it from humidity. This is followed by a heat treatment at 150 °C for 10 min. The paper sensor exhibited an electrical conductivity of 0.48 Ωcm−1 at room temperature with a linearity of 99.86 %. Remarkably, its sensitivity is 658.5 Ω/°C, which is 14 times higher than that of sensor with polyimide substrate (46 Ω/°C), for the body temperature range of 30–42 °C. The paper-based temperature sensor is implemented in a body-attachable patch for a wearable thermometer, which is simply connected with a circuit part for signal processing and the results are transferred to a phone via Bluetooth. The proposed inexpensive sensor is potentially useful for a wide range of flexible electronics and healthcare applications. [ABSTRACT FROM AUTHOR]

Piezoelectric nanogenerators (PENGs) based on micro‐fibre of polyvinylidene fluoride (micro‐fibre polyvinylidene fluoride (PVDF)). Flexible nanogenerator was developed by addition nanoparticle composition. This PENG fabricated using micro‐fibre PVDF/BaTiO3, which was deposited on paper interdigitate substrate by wire electrode free surface electrospinning method. The device from micro‐fibre PVDF performed open‐circuit voltage and short‐circuit current of 13 mV and 380 nA recently. The device from composite material addition value of open‐circuit voltage and short‐circuit current of 528 mV and 661 nA recently. [ABSTRACT FROM AUTHOR]

Freestanding, robust electrodes with high capacity and long lifetime are of critical importance to the development of advanced lithium–sulfur (Li–S) batteries for next‐generation electronics, whose potential applications are greatly limited by the lithium polysulfide (LiPS) shuttle effect. Solutions to this issue have mostly focused on the design of cathode hosts with a polar, sulfurphilic, conductive network, or the introduction of an extra layer to suppress LiPS shuttling, which either results in complex fabrication procedures or compromises the mechanical flexibility of the device. A robust Ti3C2Tx/S conductive paper combining the excellent conductivity, mechanical strength, and unique chemisorption of LiPSs from MXene nanosheets is reported. Importantly, repeated cycling initiates the in situ formation of a thick sulfate complex layer on the MXene surface, which acts as a protective membrane, effectively suppressing the shuttling of LiPSs and improving the utilization of sulfur. Consequently, the Ti3C2Tx/S paper exhibits a high capacity and an ultralow capacity decay rate of 0.014% after 1500 cycles, the lowest value reported for Li–S batteries to date. A robust prototype pouch cell and full cell of Ti3C2Tx/S paper // lithium foil and prelithiated germanium are also demonstrated. The preliminary results show that Ti3C2Tx/S paper holds great promise for future flexible and wearable electronics. [ABSTRACT FROM AUTHOR]

Paper substrates for flexible, mobile, and disposable electronic applications draw academic and commercial attention due to their many advantages, such as cost efficiency, low weight, mechanical flexibility, and environmental compatibility. For portable electronic applications, it is important that the electronic devices and circuits can be operated with voltages of a few volts, due to the limitations of mobile power supplies, such as solar cells or energy harvesting devices. Here, low‐voltage organic p‐channel and n‐channel transistors as well as unipolar and complementary ring oscillators are fabricated directly on the surface of a banknote. It is demonstrated that low‐power organic integrated circuits on paper substrates can be operated with supply voltages of less than 3 V and with frequencies of several hundred kilohertz. These results emphasize the prospects of organic transistors for smart paper applications. Low‐power organic integrated circuits on paper substrates are operated with supply voltages of less than 3 V and frequencies of several hundred kilohertz. These results emphasize the prospects of organic transistors for smart paper applications. Organic p‐channel (carrier mobility: 1.1 cm2 Vs‐1) and n‐channel transistors (0.17 cm2) as well as ring oscillators are fabricated directly on the rough surfaces of banknotes. [ABSTRACT FROM AUTHOR]

Metallized paper is patterned to create touch pads of arrayed buttons that are sensitive to contact with both bare and gloved fingers. The paper-based keypad detects the change in capacitance associated with the touch of a finger to one of its buttons. Mounted on an alarmed cardboard box, the keypad requires the appropriate sequence of touches to disarm the system., Chemistry and Chemical Biology