Photophysical properties of acid-responsive triphenylamine derivatives bearing pyridine fragments: Towards white light emission

Enhancement of Aggregation-Induced Emission by Introducing Multiple o-Carborane Substitutions into Triphenylamine

“…Another significant point was the blue-shift of the emission peak in the longer-wavelength region by increasing the number of the o -carborane units. In the previous reports on electronic properties of the donor–acceptor system including triphenylamine, similar blue-shifts of absorption and emission bands have been observed by increasing the number of electron-accepting branches [ 49 , 50 , 51 ]. Accordingly, it is implied that electron-donating ability from lone pairs of nitrogen in the center of the triphenylamine moiety should be weakened by increasing the number of electron-deficient o -carborane substituents.…”

Photophysical and Protonation Time Resolved Studies of Donor–Acceptor Branched Systems With Pyridine Acceptors

“…The value of ϵ for 1 is much larger than that of its counterpart molecule having a -CN acceptor 43 which can be ascribed to the enhanced HOMO-LUMO overlap. 34 However, for 2 a 1.5 increase of ϵ vs. 1 was expected while the increase is smaller possibly pointing to structural changes of 2 such as a deviation from the 120 0 angle among the branches. Besides, in 3, the molar extinction coefficient is almost three times that of 1 indicating an additive behavior of branches and not a co-operative one where an increase of ϵ of more than three times would be expected.…”

“…An interesting way of tuning the photophysics of the molecules bearing the above mentioned π-deficient groups is through protonation, which promotes enhanced ICT as well as redshifted fluorescence spectra originated by the protonated species. [34][35][36][37][38][39][40][41][42] EET has been identified as the underlying mechanism in such protonated systems shifting the emission from the blue (emission from the non-protonated species) to the red spectral region (emission from the protonated species). 35,37,38 The above can be also exploited for the generation of white light emitters to be used in White Organic Light Emitting Diodes (WOLEDs) providing an increased interest in these donor- acceptor molecules with heterocyclic electron acceptors.…”

“…The compounds are of dipolar, quadrupolar and octupolar nature bearing TPA electron donating core and pyridine electron acceptor(s) as well as acetylenic π-bridge. The synthesis and chemicalcharacterization of these compounds has been published in our previous work 34.…”

Carbazole‐Terpyridine Donor‐Acceptor Dyads with Rigid π‐Conjugated Bridges

“…[15,16] Among many options for the design of organic πconjugated molecules, the combination of an electron donor (D) and a related acceptor (A) is particularly interesting, as it affords "push-pull" systems, which are well suited for organic electronics, semiconductors and photovoltaics. [17] The A/D subunits can be covalently connected through different rigid and conjugated systems, so as to prepare D-π-A architectures [18][19][20][21][22][23] which may show a characteristic photophysical behaviour, in particular charge-transfer absorption (and possibly emission) bands, typically red-shifted compared to spectral features arising from local excited states centred on the individual subunits. [24] Electron-rich moieties containing fused aromatic rings can exhibit high carrier mobilities, enhanced fluorescence and reduced band gaps.…”