Enhanced Photoluminescence of Sulfur-Bridged Organic Chromophores

Abstract

A general approach to enhancing the photoluminescent quantum yield for a series of organic chromophores is presented. By bridging a chromophore symmetrically about a sulfur atom it was found that the photoluminescence could be systematically increased by oxidizing the bridge. Furthermore, the enhanced quantum yields were achieved without diminishing the solubility of these chromophores in common organic solvents. The photophysical characterization, as well as potential applications of these molecules will be discussed.

Synthesis, structure and photophysical properties of regioisomeric sulfone-bridged pyrene–thienoacenes

“…Compared with their emission from solution, the solid-state emissions are remarkably red-shifted more than 50 nm, and the efficiencies also a little lowered, which could be due to the strong intermolecular interaction at the aggregate form [12]. However, these PL efficiency value are still comparable with those of reported dibenzothiophene S,S-dioxides derivatives [6]. a Photophysical measurements in hexane (5.0 Â 10 À6 mol L À1 ) b l abs is the strong absorption peak appearing at the longest wavelength.…”

“…Two approaches have been generally applied to synthesize arylsulfones: post-oxidization, where the sulfide-bridged system is first synthesized and then oxidized [6]; and the pre-oxidization, where benzothiophene S,S-dioxides are first synthesized and then coupled with other reactant to build larger sulfone-bridged structures [10,11]. For example, Nandakumar et al recently reported the synthesis of substituted dibenzothiophenes S,Sdioxides via a Diels-Alder reaction between 1,3-diarylbenzo[c] furans and thiophene S,S-dioxide derivatives [11].…”

“…Some sulfur-bridged un-fused aromatic substituted sulfoxides and sulfones exhibit different emission properties compared to their reduced sulfide counterparts [4][5][6][7]. For example, Barbarella et al found that introduction of thiophene S,S-dioxide into conjugated oligothiophenes could offer better photoluminescence (PL) efficiency [4].…”

“…Liu et al also successfully prepared high PL efficiency polyfluorenes by incorporating dibenzothiophene-S, S-dioxide [5]. Christensen et al recently reported that the PL efficiency of some symmetrical sulfur-bridged chromophores could be enhanced by oxidizing the sulfur to sulfone [6]. In other cases, the sulfones are reported as less emissive than the reduced sulfides [7,8].…”

Aggregation-enhanced emission (AEE)-active polyamides with methylsulfonyltriphenylamine units for electrofluorochromic applications

“…To address this problem, the opposite of ACQ, aggregation-induced emission (AIE) effect which was first reported by Tang [31] paves a facile way for the design and synthesis of efficient solid-state materials. Remarkably, sulfonecontaining materials are receiving increasing attention due to their effectively enhanced photoluminescence quantum yields [32,33]. Adachi and coworkers have reported amount of TPAsulfone derivatives with interesting thermal activated delayed fluorescence (TADF) properties, ascribed to the small energy gap between the lowest single (S 1 ) and the lowest triplet (T 1 ) states resulting in strong reverse intersystem crossing (RISC) process [34e37].…”