Highly sensitive large-area multi-layered graphene-based flexible ammonia sensor

• This paper reports large-area synthesis of reduced graphene oxide (RGO) on a 3-inch diameter filter paper.
• The flexible RGO-based sensor was used to detect ammonia at room temperature. Since the sensor detects the target gas at room temperature, the power consumption and consequently the cost reduces.
• The performance of the sensor was found better than some of the recently reported performances of RGO-based ammonia sensors.
• The sensor can detect ammonia of as low concentration as 430 ppb. This is the calculated limit of detection (LOD) of the sensor.
• The sensor was tested against different volatile organic compounds (VOCs) and was found selective towards ammonia.
• Reports on flexible ammonia sensors are available but the authors could hardly find any report on flexible RGO-based ammonia sensor.

The paper reports the development of a highly sensitive, flexible and low-cost ammonia sensor. The sensing element is based on the chemically derived multilayered graphene deposited on a 3-inch diameter filter paper. The sensing material was deposited on a filter paper because it is a flexible substrate and also reduces cost. Multilayered graphene was obtained by reducing the graphene oxide (GO) using glucose. The fabricated sensor showed sensitivity to detect ammonia concentration as low as 430 ppb. The response characteristics of the sensor as a function of ammonia concentrations (varying from 400 to 4000 ppm) is reported in the paper. It also describes the variation in the response characteristics in flat and bent positions of the sensors. The reproducibility of the sensor performance is also established by the results presented in the paper.