Introduction of Materials Used in Chemical Sensors

Abstract

Since the advent of smartphone technologies, the word “sensor” has become more and more commonplace outside of the academic environment. Nowadays, it is easy to find smartphones with a variety of sensors, for example, proximity, motion, ambient light, gyroscopic, and magnetic. These sensors are devices that detect inputs from the physical environment, in order to generate an output signal that can be read and understood by a human and/or can be transmitted electrically by someone or a machine. A simple example of a sensor is the mercury-based glass thermometer that has a heat as input and as consequence of the change in temperature the liquid mercury expands, or contracts, indicating a value of the temperature measured in a calibrated marked gauge that can be detected by a natural sensor, the human eye. Basically, the physical devices highlighted above translate physical properties into a human-readable output just as some human analogues can do through, for example, touch, vision, or hearing. However, nature has given us sensorial systems responsible not only to translate physical quantities as an interpretation of the outside world, but also the ability to sense chemicals through taste and olfaction systems. This chapter will introduce key parameters in the definition of biological sensors leading to chemical sensors and will also serve as an introduction to the other chapters.