Starch (Tapioca) to carbon dots: an efficient green approach to an on–off–on photoluminescence probe for fluoride ion sensing

Photoluminescent carbon dots of 4-5 nm size were prepared from starch (Tapioca Sago) through a solution method under mild conditions. The as-prepared carbon dots were used as photoluminescence probes for highly anion selective fluoride ion detection in aqueous solutions. A ready-to-use device is also demonstrated.