Fluorene‐containing tetraphenylethylene molecules as lasing materials

Abstract

A series of star‐shaped oligofluorene molecules, each containing a TPE core, have been specifically designed and produced to show effective aggregation‐induced emission (AIE). Each molecule differs either in the number of fluorene units within the arms (e.g., 1 or 4, compounds 4 and 5), or the terminal group positioned at the end of each arm (e.g., H, TMS, or TPA, compounds 4, 6, and 7). Although they are all poor emitters in solution phase they become efficient yellow‐green luminogens in the condensed state. Their AIE properties were investigated in THF/H2O mixtures, with each molecule exhibiting a clear emission enhancement at specific water contents. An all‐organic distributed feedback (DFB) laser was fabricated using compound 4 as the gain material and exhibited an average threshold energy fluence of 60 ± 6 μJ/cm2 and emission in the green region. Furthermore, piezofluorochromism studies on a thin film of this material displayed a linear dependence of the amplified spontaneous emission (ASE) peak position on applied pressure, indicating potential applications as lasing‐based pressure sensors. © 2016 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 734–746

Tetrathiafulvalene–oligofluorene star-shaped systems: new semiconductor materials for fluorescent moisture indicators

“…The observation of aggregation by PL has also been reported for tetraphenylethene (TPE)-oligofluorene star-shaped systems. 45 Self-absorption leads to a small bathochromic shift of a few nanometres for the higher energy band in more concentrated solutions for all compounds, HU-Fn and TTF-Fn-X. In contrast to the TTF-cored oligofluorenes, compounds HU-Fn did not reveal any change in the shape of the emission profile in the range of concentrations 10 À7 -10 À5 M.…”

“…The hypsochromic shift in the solid state and the dependence of the shape of the emission profile on the concentration have been observed earlier for star-shaped oligofluorenes with a tetraphenylethene (TPE) core. 45 The electrochemical HOMO-LUMO gap values (Table 2) estimated for compounds bearing a TTF core TTF-F1 and TTF-Fn-TMS (n = 1-4) are in the range of 2.48-2.71 eV, showing that the gap is not significantly affected by extending the conjugation through additional fluorene units and that the TTF core is responsible for the initial oxidation of the materials. The oligofluorenes (HU-Fn), show an electrochemical HOMO-LUMO gap of 3.02 eV and 2.89 eV, respectively.…”

Aggregation-Induced Emission Properties in Fully π-Conjugated Polymers, Dendrimers, and Oligomers

“…Fluorene is another chromophore that has been used to functionalize the periphery of TPE [ 55 ]. Specifically, compounds 9 , 10 and 11 ( Figure 8 ) were prepared by means of Suzuki coupling conditions using Pd(PPh 3 ) 4 as catalyst and tetrabromo- TPE and boronic acid of the corresponding fluorene as reactants.…”

“…In this way, compound 9 presents an emission maximum at 409 nm with a less intense peak at 531 nm, while for compounds 10 and 11 , the most intense peak corresponds to the one with the least energy (longest wavelength): 528 nm and 523 nm, respectively, leaving the peak with the most energy relegated to a lower intensity. The authors do not report the values of quantum yield in solution but they do mention that “ the emitting properties are poor due to the nonradiative decay associated to the rotation of the arms around the ethene core ” [ 55 ]. The absorption of these compounds in solid state and film is comparable with the results obtained in solution, apart from the fact that an increase in the absorption band at lower energies is observed ( Figure 8 b).…”

Organic semiconductors based on complex diarylfluorenes via Friedel-Crafts protocols of fluorenols

“…的有机光电功能材料. 纵观有机电子领域方向的发展 历程, 芴功能化的关环或开环芴基 [12~14] 位阻半导体被 广泛应用于有机电致发光 [14,15] 、有机激光 [16,17] 、光电 传感 [18,19] 、有机太阳能电池给受体材料 [20,21] 、钙钛矿 太阳能电池 [22~25] 、光电存储材料 [26,27] 以及有机分子与 纳米器件 [28] (图1)等领域. , 虽然其活性比卤素低, 但是作为绿色试剂被广泛 研究, 早期多应用于分子内的傅克关环(邻卤二芳基合 成螺环的关键步骤) [36] , 之后扩展到稠环 [37] 、杯芳烃 [38] 和卟啉 [39] 等大环化合物.…”