Latest developments in NO? gas sensors based on PEDOT: PSS nanocomposites and metal oxides: A comprehensive review

Abstract

Nitrogen?dioxide (NO?) is toxic atmospheric contaminant having serious impacts on human health and environment. The low concentration detection of NO? in high accuracy and high sensitivity is still one?of the difficult points in air quality monitoring. Recently, hybrid gas sensors based on the conducting polymer PEDOT:PSS and metal oxide semiconductors have been proposed as potential candidates for?high-performance NO? sensing. Using the p-type polymer and n-type or p-type metal oxides in nanocomposites can lead to?a synergetic effect in terms of improved charge transport, sensitivity, and operation at lower temperatures. Recent developments in the area of PEDOT:PSS/metal oxide nanocomposite-based NO2 sensing are reviewed with?a critical look at the structural and electronic nature of PEDOT:PSS, gas-sensing mechanism of conventional metal oxides, and importance of interface engineering for device performance. It also highlights eco-friendly synthesis techniques e.g. water-based processing and green synthesis of metal?oxides, contributing to sustainable production practices for the sensors developed. Major previous works are summarized and discussed on the?basis of important performance largeness, such as the detection limit, response/recovery time/temperature/humidity and environment-friendly processing conditions. Although these hybrid systems present obvious opportunities compared with pure sensors, the issues of long-term stability, selectivity?under mixed gas environments and reproducibility of the fabrication approaches are still challenging. In general, PEDOT:PSS/metal oxide nanocomposites offer a?viable and a sustainable platform for the next-generation NO? gas sensors with lavish sensing performance, eco-compatibility, and prospects to be scaled-up for cost-effective fabrication.