Long range energy transfer in conjugated polymer sequential bilayers

Abstract

Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Steady-state and time-resolved photoluminescence have been used to investigate the optical properties of bilayer and blend films made from poly(9,9-dioctyl-fluorene-2,7-diyl) (PFO) and poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH PPV). Energy transfer has been observed in both systems. From steady-state photoluminescence measurements, the energy transfer was characterized by the effective enhancement of the MEH PPV emission intensity after exciting the donor states. Relatively faster decays for the PFO donor emission have been observed in the blends as well as in the bilayer structures, confirming effective energy transfer in both structures. In contrast to the bilayers, the time decay of the acceptor emission in the blends presents a long decay component, which was assigned to the exciplex formation in these samples. For the blends the acceptor emission is in fact a composition of exciplex and MEH PPV emissions, the later being due to Förster energy transfer from PFO. In the bilayers, the exciplex is not observed and temperature dependence photoluminescence measurements show that exciton migration has no significant contribution to the energy transfer. The efficiency and very long range of the energy transfer in the bilayers is explained assuming a surface-surface interaction geometry where the donor/acceptor distances involved are much longer than the common Förster radius.

Long‐range dipole–dipole energy transfer enhancement via addition of SiO2/TiO2 nanocomposite in PFO/MEH‐PPV hybrid thin films

“…This is consistent with the previous observations of the emission spectra in Figures (b) and (b). Moreover, this is in agreement with the results obtained by Cury and coworkers for PFO/MEH‐PPV blends …”

“…The offset between the energy levels for the MEH‐PPV and PFO suggested an exciplex formation between the donor and the acceptor. Therefore, the long decay component in the MEH‐PPV emission decay at 560 nm was attributed to the presence of the exciplex, which is in agreement with a previous report for the PFO/MEH‐PPV blend . As shown in Figures (b) and (b), the difference in the blue shifts with the peak position of the MEH‐PPV, with and without the SiO 2 /TiO 2 NC, were attributed to the overlap of the exciplex and the MEH‐PPV emission …”

Spectroscopic studies of different poly3hexylthiophene chain environments in a polyfluorene matrix

“…where k 2 is an orientation factor equal to 2/3 for randomly oriented dipoles, η d = 0.21 is the donor PLQY, [31] n = 1.9 is the refractive index of the medium, [32] considering that P3HT molecules are dispersed into PFO matrix, f D (λ) is the PL spectrum of the donor normalized by area, and ε A (λ) is the molar extinction coefficient of the acceptor.…”

Understanding molecular interactions in light-emitting polymer bilayers: The role of solvents and molecular structure on the interface quality

“…Such EET is a consequence of the F€ orster mechanism, which is enhanced due to interfacial mixing and consequent proximity of donor and acceptor molecules. 14,15 While the SY xy /PFO tl sample was found to have an interdiffusion width of 7 nm at the polymer/polymer interface, the mixing layer is only 1 nm-thick at the SY xy /PFO xy bilayer. This is contrary to the expected behavior for which the use of the same solvent leads to a more effective mixing of molecules at the heterojunction interface.…”