Nanoimprint assisted free standing porous vanadium oxide nanosheet based ammonia sensor

Abstract

Artificial intelligence in healthcare sector endures a largest share in non-invasive and point-of-care disease diagnosis by interfacing human behaviour through wearable pathway. In a view to develop sensing element for wearables, the concept of free standing poly-l-lactic acid (PLLA)/V2O5 nanosheets using sacrificial layer - (poly vinyl alcohol- PVA)method has been proposed in this work and the studies on ammonia (NH3) sensing has been briefly discussed. In a view to enhance the sensing performance of vanadium pentoxide (V2O5) film, surface modified PLLA substrates using nanoimprint lithography (NIL) have been implemented. The V+5 stoichiometry of the free standing PLLA/V2O5 films were confirmed using x-ray photoelectron spectroscopy (XPS). From field emission scanning electron microscopy (FE-SEM), it was observed that the patterned structure of about ~250 nm diameter was uniformly distributed on the surface of PLLA/V2O5 film. The chemiresistive sensing studies proved that the sensor response of V2O5 films on patterned PLLA substrate exhibited enhanced response about ~17 towards 75 ppm than the V2O5 film on unpatterned PLLA substrate. We believe that this strategy of patterned free standing PLLA/V2O5 nanosheets will help in fabricating the wearable sensors with better sensing performance.