photosensitizer
/ˌfəʊtə(ʊ)ˈsɛnsɪtʌɪzə/(also photosensitiser)
noun
1 Chemistry and Biochemistry. A substance capable of initiating a chemical reaction by absorbing light energy and transferring it to a reactant.
2 Medicine. A substance that causes photosensitization.
Origin
Early 20th century; earliest use found in Science. From photo- + sensitizer.