Preface

We are living in a society where automation with minimal or no human intervention is in great demand for all electrical devices and appliances. One of the major requirements for these smart devices is highly sensitive, long-lasting, low-cost smart sensors. A sensor is an analytical device that detects changes in the environment and converts them into a measurable analog resistance/voltage/current that can be read on a display or transmitted for further processing.

The healthcare industry demands low-cost, lab-on-chip type biosensors for simple and rapid detection of biomolecules or biogases. In the last two decades, a significant amount of research has been devoted to the development of various types of gas sensors using different nanomaterials. This book, written by scientists and researchers in the relevant professions, provides an overview of recent advances in the development of various gas sensors for the electronics and healthcare industries.

There are five chapters covering sensor basics, applications and numerical analysis. Dayekh et al. present an overview of gas-sensing technology. Mishra et al. discuss highly efficient optical-based gas sensors. Rao et al. review fiber-optic sensors and describe the use of spin-frustrated multiferroics on the surface of the fibers for the detection of volatile organic compounds. The detection of toxic gases using a metal oxide-based sensor and a commercial design is explained by Guillen Bonilla et al. In the final chapter, Hejczyk et al. describe a numerical analysis optimizing the steady-state condition of surface acoustic wave-based gas sensors.

The editors hope that this book will contribute to the development of new efficient and cost-effective gas sensors.

> **Soumen Dhara** School of Applied Sciences, Kalinga Institute of Industrial Technology, Bhubaneswar, India

> **Gorachand Dutta** School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur, India

**Chapter 1**

**Abstract**

and measurement sensitivity.

nanocomposite, NH3 gas sensor

represent as reminder for this problem [1].

**2. Classification of gas-sensitive materials**

**1. Introduction**

**Figure 1** [2].

**1**

Gas Sensor and Sensitivity

*Manar Lo Dayekh and Saleem Azara Hussain*

Gas sensors help to detect toxic and flammable gases in the atmosphere, and the use of these devices can reduce or prevent severe consequences for people and the environment. Metal oxides are one of the best materials used in the preparation of gas sensors, and they have proven in general that they have resistance to high temperatures Also, they are characterized by optical transparency at visible wavelengths, and they have a wide band gap. Whereas the interactive properties of metal oxides are the applications key chemical sensor. One of the characteristics of sensitivity is sensitivity, which is defined as the rate of change in the resistance of the thin film in the presence and absence of gas. Sensitivity is affected by several factors, including the relative humidity, the temperature of the sensors, the response time of the sensitivity, the time of exposure of the membranes to the gas, the background of the gas composition, and the thickness of the film.The chapter includes an explanation of the sensor parts

**Keywords:** gas sensing, sensitivity, gas sensitive materials, factors on gas, (Tio2/rGo)

According to the scientific and technological developments, researchers has witnessed big dealing in the study of the applications of sensor including gas sensors and for its fundamental applications in the various fields of life like industrial industries, power generation, food, and beverages, medical, and therapeutic as well as agricultural industries. As a result of current industries possesses that increasingly involve the use and manufacture of highly hazardous materials especially toxic gases and flammable create a potential hazard to industrial facilities and their employees even the people who live near them. Moreover, all events that take place in the world

According to the base of gas sensing, gas-sensitive materials are divided into two kinds based on electrochemical components and other principles, as shown in

There are three materials utilized as sensing components: metal oxide semiconductor, conductive polymer composites, and carbon nanomaterial [2].
