There is a rather longish thread on this lurking somewhere.

Basically, common Ivy can be used to extract the chlorophyll into alcohol (Everclear) and it can be used to generate a weak sensitization in the red region. Along with Erythrosine you get green and thus Pan sensitivity. These are two common approaches. A company called H. Sands in Titusville Fla. makes "real" photographic sensitizing dyes at about $100 / teeny tiny bottle of about 100 mg - 1 g depending on the dye.

Chlorophyll solution does not keep well.