The synthesis of vanadium oxide family compounds is challenging because of their affinity to exist in different oxidation states and is further intensified by the lack of suitable techniques for their direct growth on flexible substrates, thus limiting their applications in flexible electronics. In this report, we demonstrate the one-step fabrication of a two-dimensional (2D) V2O5-based versatile papertronics (paper electronics) platform on a low-cost cellulose paper substrate and its application toward broadband photodetection and resistive memories. The porous nature of cellulose paper helps in the uniform growth of 2D V2O5 not only on the surface but also in bulk, thereby assisting in the easy diffusion of silver ions (Ag+) in the defect sites of V2O5, unlike in conventional flexible polymeric substrates, thereby assisting in the resistive switching mechanism. 2D V2O5 on a cellulose-paper-based memory exhibited an ON/OFF ratio of 3.5 × 102 and V set and V reset voltages of ∼+1 and −1 V, respectively, with excellent endurance and retention capacity of up to 500 cycles. The synthesized 2D V2O5 nanosheets exhibited broadband absorption ranging from ultraviolet (UV) to visible with an optical band gap calculated as 2.4 eV, making it suitable for broadband photodetection. Responsivities under UV- and visible-light illumination were found to be 31.5 and 20.2 mA/W, respectively, which are better than those of V2O5-based photodetectors fabricated using sophisticated methods. The fabricated broadband photodetector exhibited excellent mechanical stability with excellent retention in responsivity values over 500 cycles. The strategy outlined here presents a novel, low-cost, and one-step approach for fabricating devices on paper that find wide applications in flexible electronics.

Electronic Skin is arousing a lot of interest in recent years due to its ability to mimic human skin and also its excellent conformability. Even though there are reports on...

Monitoring of personal healthcare requires multifunctional sensors that can sense both chemical and physical stimuli. One of the possible solutions is the fabrication of low-cost, disposable "one time use" functional nanomaterials based sensors that can sense multiple health parameters, and the sensor data can be wirelessly transmitted to the smartphone for further processing. This report is a first demonstration of the direct growth of NiSe 2 on cellulose paper by the solution processed hydrothermal method and its application for a smart personal healthcare monitoring system that includes a noninvasive periodontal diagnosis to monitor oral health by the use of human saliva, a breath analyzer for various breath-related diseases, and a gesture sensor for deaf, dumb, and aurally challenged patients to communicate with the world. The fabricated sensor can be customized for a specific sensing with a dedicated user-friendly Android application which can be accessed remotely by a smartphone. The detailed sensing mechanism of each sensor is explained in terms of charge transport and electron transfer mechanisms. Furthermore, the sensing performance does not fluctuate even after 500 bending cycles for both chemical and physical stimuli, thus enabling low-cost yet robust and reliable monitoring. Successful development of such a versatile platform finds wide applications in the field of smart healthcare, medical devices, and the internet of things.

The challenges involved in realizing next-generation applications, like robotics, artificial electronic skin, noninvasive healthcare monitoring, motion detection, and so forth, enabled with wireless human-machine interfaces, present a growing need for high-performance flexible and wearable multifunctional electromechanical sensors. In this regard, emerging classes of two-dimensional nanomaterials and their hybrids show excellent promise as active sensing materials, given their high flexibility and remarkable sensitivity to external pressure and strain. This report is the first demonstration of SnS/Ti3C2T x nanohybrid-based electromechanical sensors for use in applications like sign-to-text translation and sitting posture analysis. The as-fabricated piezoresistive sensor exhibits a high gauge factor and sensitivity value, that is, 7.41 and 7.49 kPa–1, respectively. Furthermore, the nanohybrid-based sensor displayed a negligible change in performance over ∼3500 and ∼2500 cycles for both pressure and strain characterizations, indicating high robustness and exceptional stability. The underlying intrinsic piezoresistive mechanism in layered nanomaterials and the Ohmic contact formed at the SnS/Ti3C2T x heterojunction are explained in detail with the help of energy band diagrams wherein the work function and the E homo values are extracted experimentally by ultraviolet photoelectron spectroscopy for both SnS and Ti3C2T x . The successful demonstration of sign-to-text translation and e-cushion applications using SnS/Ti3C2T x nanohybrid-based piezoresistive sensors will further expand the scope of flexible and wearable electronics research.