Solvent-Free Luminescent Organic Liquids
Solvent-Free Luminescent Organic Liquids
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DOI：
10.1002/anie.201108853
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发表时间：
2012-01-01
影响因子：
16.6
通讯作者：
Nakanishi, Takashi
中科院分区：
文献类型：
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作者：
Babu, Sukumaran Santhosh;Aimi, Junko;Nakanishi, Takashi
有机电子学的一个前瞻性研究方案[1]利用非共价相互作用来组装光电活性分子[2]，以提高器件的性能，如场效应晶体管[3]和太阳能电池[4]，因为它可以实现简单和廉价的制造以及容易的缺陷退火。为了与无机材料竞争，需要对有机物质进行最大程度的关注，从分子设计到自组织，以可预测的方式制造成设备，最后到最终使用具有改进性能和寿命的应用。[4，5]因此，应在这方面考虑其他性质不同的办法。光电子功能材料的软化是朝向可印刷有机电子器件的一个这样的实例。无溶剂有机材料的配方，如离子液体，[6]含有纳米颗粒的离子液体，[7]或有机发色团，[8]是一个新兴且具有挑战性的领域，旨在寻找自组装有机半导体的替代品。[9]最近，不带电荷的室温有机液体已经被引入作为新的功能液体，通过使用低粘度有机链隔离π-核。室温下，无溶剂的有机液体，如酞菁，[10]卟啉，[11]咔唑[12]和富勒烯[13]已经被报道为这一概念的证据。然而，要提供出色的最终用途性能和有意义的应用程序还为时过早。在室温下使用有机液体预期提供若干益处，例如，非挥发性、在无溶剂条件下的加工、可调谐的光电功能、高密度的电子活性π-共辄部分或充当其它有机或无机组分的溶剂/基质的能力。此外，液体材料是易处理的，并且可以容易地处理和以批量规模使用。选择线性π共轭分子oligo（p-phenylenevinylene）（OPV）作为功能核心部分。OPV由于具有优异的稳定性和发光特性，以及自组装特性，在有机光电子领域得到了广泛的研究。[2，1 - 4]在本文中，我们报道了一系列室温液体OPV（1-4，图1a）的合成，以及它们作为溶剂/基质和蓝光发射组分用于制备发射白色光的液体油墨的用途。这项研究为发光液体铺平了道路，这种发光液体可以涂在具有不同几何形状的各种表面上。室温，无溶剂，液体OPV是通过用低粘度烃类（如支链脂肪链）取代两种不同的OPV核来合成的（图1a）。例如，未偶联的支链烷基溴（2b）和偶联至苯甲醛（2a）的支链烷基溴（辅助信息中的方案S1）在ω= 10 rad sq-1的角频率下的复数粘度（η*）分别为1.03和0.01 Pas（辅助信息中的图S1）。分子设计策略，包括烷基链取代基的位置和链支化的程度（图1a），对于调节液体的物理特性非常重要。目标支链偶联OPV衍生物1-4在室温下作为浅黄色粘性流体获得，而参比分子5和6为固体。所有的OPV衍生物通过1H NMR光谱和MALDI-TOF质谱明确地鉴定。液体的1H NMR光谱（支持信息中的图S2）和热重分析（TGA，支持信息中的图S3）表明不存在......
A prospective research scenario of organic electronics [1] utilizes noncovalent interactions to assemble optoelectronically active molecules [2] to attain improved performance in devices, such as field-effect transistors [3] and solar cells,[4] because it may enable simple and cheap manufacture as well as easy defect annealing. In order to compete with inorganic materials, utmost care is needed for organic substances, from molecular design to self-organization, fabrication into devices in a predictable way, and finally to enduse applications with improved performance and longevity.[4, 5] Therefore, alternative and qualitatively different approaches should be considered in this direction. Softening of the optoelectronic functional materials is one such example towards printable organic electronics. The formulation of solvent-free organic materials, such as ionic liquids,[6] ionic liquids that contain nanoparticles,[7] or organic chromophores,[8] is an emerging and challenging area which aims to find replacements for self-assembled organic semiconductors.[9] Recently, uncharged room-temperature organic liquids have been introduced as new functional liquids by isolating the π-core through the use of low-viscosity organic chains. Room-temperature, solvent-free organic liquids, such as phthalocyanines,[10] porphyrins,[11] carbazoles [12] and fullerenes [13] have been reported as proof of this concept. However, it is still premature to deliver excellent end-use performance and meaningful applications. The use of organic liquids at room temperature is expected to provide several benefits, for example, nonvolatility, processing under solventfree conditions, tunable optoelectronic functions, a high density of electronically active π-conjugated moieties, or the ability to act as solvent/matrix for other organic or inorganic components. Furthermore, the liquid materials are tractable, and can be easily treated and used on a bulk scale. The linear π-conjugated molecule oligo (p-phenylenevinylene)(OPV) was chosen as the functional core moiety. OPV has been widely studied in organic optoelectronics because it has excellent stability and emission characteristics, as well as self-assembly properties.[2, 14] Herein, we report the synthesis of a series of room-temperature liquid OPVs (1–4, Figure 1 a), as well as their use as a solvent/matrix and a blueemitting component for the preparation of liquid inks that emit white light. This study paves the way to light-emitting liquids which can be painted onto various surfaces that have different geometries.Room temperature, solvent-free, liquid OPVs were synthesized by substituting two different OPV cores with lowviscosity hydrocarbons, such as branched aliphatic chains (Figure 1a). For example, the complex viscosities (η*) of the branched alkyl bromide uncoupled (2b) and coupled to benzaldehyde (2a)(Scheme S1 in the Supporting Information) are 1.03 and 0.01 Pas, respectively, at an angular frequency of ω= 10 rad sÀ1 (FigureS1 in the Supporting Information). The molecular design strategy, which includes the position of the alkyl chain substituent and the extent of chain branching (Figure 1a) are extremely important to tune the physical features of the liquid. The targeted branched chain, coupled OPV derivatives 1–4 were obtained as pale yellow viscous fluids at room temperature, whereas the reference molecules 5 and 6 were solids. All of the OPV derivatives were unambiguously identified by 1H NMR spectroscopy and MALDI-TOF mass spectrometry. The 1H NMR spectrum (Figure S2 in the Supporting Information) and thermogravimetric analysis (TGA, FigureS3 in the Supporting Information) of the fluids indicates the absence of …