V2O5 Nanosheets for Flexible Memristors and Broadband Photodetectors

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 X 10(2) and V-set and V-reset voltages of similar to+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.