Applications of LEDs in optical sensors and chemical sensing device for detection of biochemicals, heavy metals, and environmental nutrients

This study examined the applications of chemical sensing devices integrated with LEDs in the range between UV and IR (247-3800 nm). These chemical sensors are used to detect heavy metals, toxins and toxic gases, environmental nutrients, as well as biochemicals and biohazard related compounds. The possible shortcomings of some reviewed applications are discussed, with suggestions or likely resolutions provided. Orange, yellow, and green LEDs, which are less used in other scientific studies, are found to prevail in sensing device applications. A table that includes the findings covered in this paper has been compiled to list some common types of LEDs and their respective uses in the areas of interest. As the fifth paper of a series that discuss LEDs' applications in scientific researches, this review leads to the conclusion that LEDs have become the prominent light sources of chemical sensors and are well qualified to succeed its more energy demanding counterparts in and beyond the reviewed areas.