| 초록 |
The influence of π-conjugation structural changes on photoinduced electron transfer (PET) and intramolecular charge transfer (ICT) processes in π-conjugated donor-acceptor dyads (D-π-A) was investigated. Three types of D-π-A dyads [D-π-A (1), D-πtw-A (2), and D-π-Si-π-A (3)] were prepared. In these dyads, carbazole and oxadiazole moieties acted as electron donor and acceptor, respectively. The emission maxima of dyads, 1 and 3 red-shifted with the increase in polarity, which could be attributed to the ICT process. The fluorescence lifetimes for dyads 1 and 3 were 2.64 and 4.29 ns in CH2Cl2, respectively. In contrast, dyad 2 showed dual emission at 350 and 470 nm in CH2Cl2. The emission of dyad 2 at 380 nm corresponded to the monomer fluorescence in the locally excited state, and emission at 470 nm increased with the diminishing of the fluorescence at 380 nm. This emission band can be assigned as the intramolecular exciplex emission, and showed a strong solvatochromic shift. |
