Hand-Print method for preparation of large area and binder free electrodes for photodetection and electrocatalytic hydrogen evolution.

• Flexible film of Ag decorated WSe 2 on a paper substrate for visible light (390–780 nm) photodetection and electrocatalysis for hydrogen evolution reaction (HER) • A facile handprint technique, and drop cast methods were used to fabrication of flexible electrode without the use of binders and toxic liquids. • The pave of WSe 2 crystals on paper was followed facial, cost-effective, non-toxic, environmentally friendly handprint technique. • The performance of the photodetector was tested under bending, folding, and twisting state to determine the flexibility of photodetector. • The photodetector advocates the photoresponsivity (0.43 mA/W) and a specific detectivity (2.9 × 108 Jones) at 780 nm at low bias of 1.0 V. • The HER performance of the fabricated paper-based WSe 2 /Ag electrode were carried out by linear sweep voltammetry (LSV), cyclic-voltammetry, Tafel slope, chronopotentiometry, and electrochemical impedance spectroscopy (EIS) • The WSe 2 /Ag catalyst film require an overpotential of −341 mV for HER at a current density of −10 mA/cm2, which is significantly lower than pristine WSe 2. • This study opens new opportunities for the application of the paper-based flexible devices, and convenient electrodes for electrocatalysis. Modern life is gravitating toward the light harvesting and clean energy production route because fossil fuels are becoming obsolete, which propels the researcher and scientific community to requirements of future photo-sensing and energy inventive devices based on two dimensional (2D) nanomaterials. Herein, we present the fabrication of a flexible film of Ag decorated WSe 2 on a paper substrate for visible light (390–780 nm) photodetection and electrocatalysis for hydrogen evolution reaction (HER). A facile handprint technique, and drop cast methods were used without the use of binders and toxic liquids. The photodetector advocates the photoresponsivity (0.43 mA/W) and a specific detectivity (2.9 × 108 Jones) at 780 nm at a low bias of 1.0 V. The WSe 2 /Ag catalyst film requires an overpotential of −341 mV for HER at a current density of −10 mA/cm2, which is significantly lower than pristine WSe 2. The stability of the WSe 2 /Ag electrode for a long time interval of 15 h indicates chemical robust behavior towards HER reaction. This research opens up the versatile possibility of energy harvesting, and photoconductive devices based on heterostructures. [ABSTRACT FROM AUTHOR]