photosensitize
/ˌfəʊtəʊˈsɛnsɪtʌɪz/(also photosensitise)
verb
1 [with object] Chemistry and Biochemistry. Of a substance: to initiate (a chemical change) by absorbing light energy and transferring it to a reactant.
2 [with object] To make photosensitive.
Origin
Early 20th century. From photo- + sensitize. Compare slightly earlier photosensitized, photosensitizer.