In this paper, radiative and nonradiative energy transfer from laser dye pyrromethene 567 （PM567） and pyrromethene 580 （PM580） as donors to cresyl violet 670 （CV670） as acceptor in ethanol are investigated by using the steady-state emission measurement and the second harmonic generation （532 nm, ～ 13 ns） of a Q-switched Nd：YAG laser as the pumping source. The fluorescence intensity of the acceptor is improved due to the introduction of the donors, and the largest enhancement is obtained to be 128% in the PM567：CV670 dye mixture system. Energy transfer parameters, including the radiative and nonradiative energy transfer rate constants （KR and KNR）, critical distance （R0）, and half quenching concentration （[A]1/2） are investigated using the Stern–Volmer plots, and the acceptor concentration dependencies of radiative and nonradiative transfer efficiencies are also obtained. The values of KR for PM567：CV670 and PM580：CV670 systems are 2032.0×109 L·mol-1·s-1 and 2790.4×109 L·mol-1·s-1, respectively, and the values of corresponding KNR are 3.3×109 L·mol-1·s-1 and 4.2×109 L·mol-1·s-1, respectively. The results indicate that the dominant mechanism responsible for the energy transfer in the dye mixture systems is of the radiative type.
