Fig. 8
From: Folic acid-CdTe quantum dot conjugates and their applications for cancer cell targeting
An schematic illustration of the energy transfer process from folic acid to CdTe quantum dots. ηET is the energy transfer rate, τd is the emission decay rate of the donor (folic acid), and τa is the emission decay rate of the acceptors (CdTe quantum dots). In this process, if the lifetime of the donor is extremely short relative to the lifetime of the acceptor, no appreciable energy transfer occurs