Photoluminescence behavior of riboflavin and lumiflavin in liquid solutions and solid films

► Delayed fluorescence and phosphorescence spectra of flavins in starch films measured. ► Quantum yield of singlet-triplet intersystem determined with a new approach. ► Theory developed for determination of luminescence quantum yields of films. ► Delayed fluorescence and phosphorescence lifetimes of flavins in starch films measured. ► Singlet and triplet relevant parameters of riboflavin and lumiflavin determined.