“…The intense emission, high quantum efficiency, and long PL lifetime for both solutions are closely related to the large energy gap between 5 D 4 and its next lower lying 7 F J (J = 3, 4, 5, 6) states of Tb 3+ . [15] The weaker PL intensity, lower quantum yield, and shorter PL lifetime of NCs after biotinylation may be due to nonradiative-relaxation-induced PL quenching associated with the surface high-energy vibronic groups [16] (N À H and C À N) of biotin, as already revealed in the FTIR spectra.…”