Fluorescence and host-guest energy transfer in polymeric chains

Energy Transfer from Poly(Vinyl Carbazole) to a Fluorene‐Vinylene Copolymer in Solution and in the Solid State†

“…In solutions, PVK absorbs in the UV spectral range and emits from 350 to 500 nm (λ exc = 290 nm; peak at 399 nm with a long red‐edge tail). No vibronic structure was observed, and, for these solutions, the PL is characteristic of excimers or, as may be expected for the solid state, ground‐state aggregates (28–35). Compared to the spectra obtained in solutions, the PVK emission band is redshifted by 25 nm.…”

“…PVK absorbs in the UV range and emits from 350 to 500 nm (λ exc = 290 nm) as a broader band. This emission is very characteristic of the PVK excimers (peak at 372 nm with a longer red‐edge tail; 27–35). The shoulder in the PL spectrum at approximately 340 nm may be ascribed to the isolated lumophores.…”

“…The steady‐state emission of the isolated carbazolyl groups is observed as a shoulder in the blue‐edge of the emission band centered at λ em = 400 nm; thus, the component with τ F1 = 1.83 ns may be attributed to the carbazolyl groups undergoing quenching due to their proximity to longer sequences of carbazolyl moieties. The slower component may be attributed to excimer emission (28–35).…”

“…The steady-state emission of the isolated carbazolyl groups is observed as a shoulder in the blue-edge of the emission band centered at k em = 400 nm; thus, the component with s F1 = 1.83 ns may be attributed to the carbazolyl groups undergoing quenching due to their proximity to longer sequences of carbazolyl moieties. The slower component may be attributed to excimer emission (28)(29)(30)(31)(32)(33)(34)(35). Figure 2 also shows a strong overlap between the PL spectrum of the PVK and PFO-MEHPV electronic absorption spectra, suggesting that mixtures of these two materials may undergo either FRET or trivial energy transfer from PVK to the polyfluorene.…”

Investigation of purity and fluorescence of poly[N6-(9H-carbazol-9-ylcarbonyl)-L-Lysine] preparations

“…30,32,33 In dioxane solution the host PVCz (monomer (A = 370 nm) plus excimer (A = 410 nm) type) fluorescence was quenched by V5BCz guest units and the guest emission appeared. It is, however, relevant to compare the present fluorescence spectra with, on one hand, those of the homopolymers poly(N-vinyl-9H-carbazole) ( P V C Z )~,~~-~O and poly(Nvinyl-5H-benzo[b]carbazole) ( P V~B C Z )~~,~~ and, on the other hand, those of copolymers of N-vinyl-9H-carbazole (VCz) with N-vinyl-5H-benzo[ blcarbazole For PVCz the long-wavelength ( A, , -420 nm) emission was attributed to an intrachain excimer state4,28,30 and the shorter wavelength (Amm -380 nm) emission was attributed to either a normal carbazole molecular floure~cence~~~~ or a second excimer e m i s~i o n .~!~~ Depending on the polymerization conditions (radical or cationic) different fluorescence spectra were obtained for PV5BCz.…”