Alternatives to Ferric ammonium citrate and Oxalate, when it comes to photo linking CMC are photoinitiators:

Irgacure 2959

Lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP)

2,2'-Azobis[2-methyl-N-(2-hydroxyethyl)propionamide] (VA086)

All 3 things are really expensive though. But you only need a tiny amount.