Orotic acid-capped Tb(III)-doped calcium sulphate nanorods for the selective detection of tryptophan.

Lanthanide-based luminescent materials have gained huge attention due to their applications in optoelectronic devices, sensing, bio-imaging, anti-counterfeiting, and more. In this work, we report a luminescence-based sensor for the detection of tryptophan using orotic acid-capped Tb-doped CaSO nanorods (NRs). Orotic acid (OA) was found to play a dual role as a capping agent to control the growth of the nanorods and as a sensitizer for Tb ions.