Chemiresistive Materials for Alcohol Vapor Sensing at Room Temperature

The development of efficient sensors able to detect alcoholic compounds has great relevance in many fields including medicine, pharmaceuticals, food and beverages, safety, and security. In addition, the measurements of alcohols in air are significant for environmental protection because volatile alcohols can have harmful effects on human health not only through ingestion, but also through inhalation or skin absorption. The analysis of alcohols in breath is a further expanding area, being employed for disease diagnoses. The analyses performed by using chromatography, mass-spectrometry, nuclear magnetic resonance, ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, or Raman spectroscopy often require complex sampling and procedures. As a consequence, many research groups have focused their efforts on the development of efficient portable sensors to replace conventional methods and bulky equipment. The ability to operate at room temperature is a key factor in designing portable light devices suitable for in situ real-time monitoring. In the present review, we provide a survey of the recent literature on the most efficient chemiresistive materials for alcohol sensing at room temperature. Remarkable gas-sensing performances have mainly been obtained by using metal oxides semiconductors (MOSs), metal organic frameworks (MOFs), 2D materials, and polymers. Among 2D materials, we mainly consider graphene-based materials, graphitic carbon nitride, transition metal chalcogenides, and MXenes. We discuss scientific advances and innovations published in the span of the last five years, focusing on sensing mechanisms.