Ultrafast electron transfer in acceptor substituted bianthryl derivatives

Deep blue polymer light emitting diodes based on easy to synthesize, non-aggregating polypyrene

“…The distinct similarity of the fluorescence spectra in solution and in solid state provides good evidence for the absence of aggregation in the excited state of the compound which on the one hand stems from the strong steric hindrance caused by the tert-butyl-groups at the 7-position and on the other hand is based on the high dihedral angle between two adjacent monomer units [16]. As documented by many examples in literature, unsubstituted pyrene [18], and macromolecules containing pyrene moieties [19,20] typically display a strong solvatochromic effect as a consequence of the influence of solvent polarity on the molecular conformation. To investigate this influence on the photoluminescence and absorption of PPyr a series of solvents with increasing polarity (CH, TOL and ACN) has been tested.…”

“…Since the respective solutions exhibited a slight turbidity the broadening is attributed to scattering of light by not fully dissolved polymer particles. From a comparison to pyrene dimers having a 1,1-coupling the bathochromic shift can be assigned to the formation of a charge transfer state in solvents with higher polarity, forcing the highly twisted molecules into a more planar structure yielding the observed change of the photoluminescence [20][21][22][23]. Remarkably the shift observed in the photoluminescence of different solutions can also be partly found in a series of thin films spin coated from the mentioned solvents.…”

Synthesis and Photophysical Properties of Pyrene-Based Multiply Conjugated Shaped Light-Emitting Architectures: Toward Efficient Organic-Light-Emitting Diodes

“…However, the fluorescence spectra of 74 exhibit a remarkable long-wavelength tailing as well as additional emission bands with maximum at 493 and 530 nm. To recognize and verify the most probable explanation for the substantially red-shifted band in the case of 74, concentration dependence of the fluorescence, solvatochromic shifts of the emission maximum (Jurczok et al, 2000;Fogel et al, 2007), and time-resolved measurements of the fluorescence are investigated. These facts together indicated that the red-shifted broad emission bands are not caused by aggregation, but by intramolecular energy redistribution between the vibrational manifold of the single polymer chain (VandenBout et al, 1997;Becker et al, 2006).…”

Addressing Charge‐Transfer and Locally‐Excited States in a Twisted Biphenyl Push‐Pull Chromophore

“…Different substitutions and derivatizations have been performed on those systems, [12][13][14]17,[22][23][24][25][26][27] in order to facilitate or inhibit the motion along the coupled nuclear coordinate and investigate its effects on the charge-transfer process. [17][18][19]23,26] In this paper, we investigate a push-pull substituted biphenyl compound (hereafter TBP) where the electron-donor and the electron-acceptor groups are connected to the biphenyl central core via extended π-conjugated bridges favoring long-distance electron transfer. The interaction with the solvent plays a strong role in electron-transfer processes since charge-transfer states are characterized by large permanent dipole moments and hence strongly interact with polar solvents.…”

“…Substituted and/or rigidified dialkylaminobenzonitriles, [10,[12][13][14][15] bianthryl molecules, [16][17][18][19][20][21] substituted biphenyl derivatives [22][23][24][25][26] have been extensively investigated as model systems to unravel the vibrational and solvation effects in photoinduced intramolecular electron transfer. All these molecules are characterized by at least one conformational degree of freedom strongly coupled to the charge-transfer process: the rotation of the amino group in aminobenzonitriles, the angle between the planes of the two anthryl or phenyl rings in bianthryl and biphenyl derivatives.…”