Comments on the classical theory of energy transfer

Abstract

Energy transfer from an emitting molecule to an absorbing half−space is considered from the viewpoint of electromagnetic theory. The lifetime of a dipole emitter in the presence of a mirror is determined through a calculation of the complex Poynting vector in the dielectric surrounding the dipole. This method has the advantage over previous approaches to this problem in that the radiative and nonradiative components of the lifetime expression may be rigorously separated. The influence on emitter lifetime of a mirror of finite thickness is also described. A simple expression is derived describing the energy transfer rate in these layered systems. It is shown that nonradiative energy transfer results from coupling of the near field of the dipole to the surface plasmon modes in the metallic absorber. The Förster energy transfer rate law is discussed in the context of the present theory.

Migration-assisted energy transfer at conjugated polymer/metal interfaces

“…͑3͒, which results in derivation of an energy-transfer range of 7.5 nm for the aluminum electrode. The reduction of the energy-transfer distance as compared to gold is predicted by theory 7 and is in qualitative agreement with the higher imaginary part of the complex refractive index of aluminum ͑K 2 = 6.33͒ in comparison with gold ͑K 2 = 2.86͒. 28,29 With the energy-transfer range x 0 known we can simulate exciton density profiles at the polymer/Al interface, using x 0 and D as input parameters.…”

“…In a recent study an exciton diffusion coefficient of 3 ϫ 10 −4 cm 2 / s for NRS-PPV has been deduced. 14 The distance ͑x͒ dependence of the nonradiative decay rate constant r me for organics in front of metal interfaces has been studied both experimentally 19,20 and theoretically, 7 where a general expression has been derived within classical light reflection theory. For the case of interest, corresponding to a small distance between emissive molecule and metal in comparison with the resonant wavelength, it can be approximated with a x −3 dependence 7,21…”

“…This has been demonstrated to be important for highly luminescent conjugated polymers; 3 radiative exciton lifetime modification increases with increasing luminescence quantum efficiency of the material and becomes distinct at long distances from the metal interface. 7,8 A detailed theory of an oscillating dipole and energy transfer near metal interfaces has been developed 9,10 and agreement between experiment and theory has been demonstrated by Chance and co-workers. 7,11 It should be noted that for calculating the lifetime ͑or quantum efficiency͒ of the luminescence of a conjugated polymer near a metal interface additional assumptions about the dipole orientation and intrinsic quantum efficiency need to be made.…”

On the function of a bathocuproine buffer layer in organic photovoltaic cells

“…This interaction can result in excitations such as electron-hole pairs, phonons, or surface plasmons inside the metal and thus quench the molecular exciton. 10,11 In contrast to sample 1 significant PL is observed in sample 2, clearly showing the PL spectrum of C 60 . Evidently the exciton quenching properties of the C 60 -Al interface depend strongly on the deposition sequence.…”

Enhanced fluorescence cell imaging with metal-coated slides

“…For instance, this can be made by setting the emitter close to a reflective (dielectric or metallic) surface. The interaction of a point emitter with a planar mirror has been described by a number of authors (5,(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19). Drexhage (5,9) used this configuration for the first time to verify experimentally the modification of the spontaneous emission rate.…”