Tuning the Intramolecular Charge Transfer Emission from Deep Blue to Green in Ambipolar Systems Based on Dibenzothiophene S,S-Dioxide by Manipulation of Conjugation and Strength of the Electron Donor Units

Abstract

The efficient synthesis and photophysical properties of a series of ambipolar donor-acceptor-donor systems is described where the acceptor is dibenzothiophene S,S-dioxide and the donor is fluorene, carbazole, or arylamine. The systems exhibit intramolecular charge transfer (ICT) states (of variable ICT character strengths) leading to fluorescence emission ranging from deep blue to green with moderate to high photoluminescence quantum yields. The emission properties can be effectively tuned by systematically changing the position of substitution on both donor and acceptor units (which affects the extent of conjugation) and the redox potentials of the donor units. The results are supported by cyclic voltammetric data and TD-DFT calculations.

Synthesis and optical and electrochemical properties of polycyclic aromatic compounds with S,S-dioxide benzothiophene fused seven rings

“…[24] Moreover, they synthesized hyperbranched polymers containing alkylated FSO unit as host materials with a highly triplet energy level for green phosphorescent PLEDs, where it achieved a maximum LE of 50.5 cd A -1 as well as a maximum external quantum efficiency (EQE) of 15.3%. [28] Furthermore, they synthetized the alkylated FSO unit and introduced it into the PFO backbones which exhibited a highly pure deep-blue emission with a highly triplet energy level. [26] At the same time, Bryce et al introduced FSO unit into the fluorene based oligomers, which increased the electron affinity and achieved highly fluorescent co-oligomers with bright blue emission both in solution and in film.…”

Synthesis and photochemical properties of 3,6-di-tert-butyl-9H-carbazole derivatives

“…Thus, carbazole derivatives are used as synthons for preparation of luminophores [7], and branched 3,6disubstituted derivatives of carbazole are applied as building blocks for creation of more complex organic molecules [8]. Compounds of this type are now used for the synthesis of OLEDs because of their high hole conductivity, photochemical stability, and electroconductivity [9][10][11]. The carbazole-based dendrites are shown to act as luminescent gelators for ordered organogels [16,17].…”

Novel organic dyes based on phenyl-substituted benzimidazole for dye sensitized solar cells

“…This result points out the more polar form of its excited state in methylene chloride as compared to that of in chloroform [35,36]. Large Stokes shifts (in the range of 9156e18046 cm À1 in chloroform and 16555e22945 cm À1 in methylene chloride) suggest the generation of CT complex [37,38]. Interestingly, BI5b gives a blue-shift from 542 nm in chloroform to 510 nm in methylene chloride.…”