Controlling the Interaction of Light with Polymer Semiconductors
Controlling the Interaction of Light with Polymer Semiconductors
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DOI：
10.1002/adma.201300881
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发表时间：
2013-09-20
影响因子：
29.4
通讯作者：
Stingelin, Natalie
中科院分区：
文献类型：
--
作者：
Hellmann, Christoph;Paquin, Francis;Stingelin, Natalie
有机半导体，如π共轭聚合物，在过去的几十年里一直是一个密集的研究主题，包括阐明它们的基本光电性质，描述了这类材料的许多有趣的特征。这一重大的研究工作导致了这些用于有机光伏(OPV)、发光二极管(OLED)、晶体管(FET和LEFET)和激光器的功能大分子的工业化开发[1]，这些系统的许多新的令人兴奋的特征不断被揭开。共轭聚合物的吸收行为对于这些应用中的许多可以说是最重要的材料性质之一，因为它在决定它们的光电特性和响应方面起着至关重要的作用；[2]因此，开发简单而有效的策略，通过改变分子组装和有序性，从一开始就控制共轭大分子的光吸收(和发射)，对于进一步了解这类有趣的材料，以及它们在‘塑料电子’产品中的广泛应用，具有重要的潜力。通过加工手段来调节光与共轭有机材料的相互作用的一个很有前途的策略是共混。例如，以聚(3-己基噻吩基)(P3HT)--研究最广泛的大分子半导体之一--为例，其光学性质受合适的宿主介质的存在的影响。初步证据表明，例如，通过利用P3HT在给定溶剂中的溶解度的温度依赖性，或者通过改变“好的”和“差的”溶剂的混合物中的溶剂极性，P3HT聚集体形成(在溶液中)具有不同的微结构特征，揭示了链间和链内π-电子相互作用之间的敏感相互作用。研究表明，P3HT纳米颗粒的光学跃迁能(在吸收和发射实验中)受到去离子水(DI)在高压灭菌器中温度高达150摄氏度的水热(极性)处理的影响。在将P3HT与极性聚合物聚氧乙烷(PEO)共混并从极性溶剂混合物中纺丝后，观察到P3HT纳米纤维的光学性质发生了类似的变化。[5]还有一些研究表明，通过与聚乙二醇(PEG)共混，P3HT薄膜的光学吸收光谱发生了轻微的红移，而不需要额外的极性溶剂添加剂。[6]这些初步研究有力地表明，向P3HT中添加极性介质可以用来调整其光吸收和发射线的形状。然而，这些光学性质变化的起源以及它们可以在多大程度上以受控的方式进行操纵，还没有得到严格的证明。在这里，我们证明了共轭聚合物体系与PEO的共混使一系列共轭聚合物的光吸收发生了强烈的红移，包括P3HT，液晶聚[2，5-二(3-十四烷基噻吩基)硫代[3，2-b]噻吩基](PBTTT)，给-受体材料聚[9，9-二辛基-2，7-二基)-ALT-(4，7-双(3-己基噻吩基-5-基)-2，1，3-苯并噻二唑-2‘，2’-二基](F8TBT)，以及固态的发光聚合物，例如聚(2-甲氧基-5-(3‘，7’-二甲基酪氧基)-1，4-苯亚甲基)(MDMO-PPV)和聚(9，9-二正辛基-2，7-二基)(PFO)。我们将证明，这种转变很可能是由于在…存在下共轭聚合物主链的平坦化
Organic semiconductors, such as π–conjugated polymers, have been a subject of intense investigation over the last decades that covered the elucidation of their basic optoelectronic properties describing many of the interesting features of this class of materials. This significant research effort has led to the industrial exploitation of these functional macromolecules for use in organic photovoltaics (OPVs), light-emitting diodes (OLEDs), transistors (FETs and LEFETs) to lasers,[1] and many new exciting features of these systems are continuously unravelled. The absorption behaviour of conjugated polymers is for many of these applications arguably one of the most important material properties, because it plays a crucial role for determining their optoelectronic characteristics and response; it also can provide an indication of the microstructural order in a given architecture.[2] Therefore, developing simple and effective strategies to manipulate the optical absorption (and emission) of conjugated macromolecules from the outset through changes in their molecular assembly and ordering has significant potential for gaining further understanding of this interesting class of materials, but also for their wide spread utilization in ‘Plastic Electronic’products.One promising strategy that enables the tuning of the interaction of light with conjugated organic materials through processing means is blending. In the case of poly (3-hexylthiophene)(P3HT)–one of the most extensively investigated macromolecular semiconductors–the optical properties were, for instance, influenced by the presence of a suitable host media. Initial evidence showed that, eg by exploiting the temperature dependence of the solubility of P3HT in a given solvent or by varying the solvent polarity in mixtures of “good” and “poor” solvents, aggregates of P3HT were formed (in solution) with distinct microstructural signatures revealing the sensitive interplay between inter-and intrachain π–electron interactions.[3] Furthermore, Lee et al. showed that the optical transition energies (both, in absorption and emission experiments) of P3HT nanoparticles are affected by a hydrothermal (polar) treatment with deionised (DI) water at temperatures of up to 150 C in an autoclave.[4] In addition, Kim et al. observed similar changes in the optical properties of electrospun P3HT nanofibers after blending the P3HT with the polar polymer poly (ethylene oxide)(PEO) and spinning them from polar solvent mixtures.[5] Still others have demonstrated a minor red-shift in the optical absorption spectrum of P3HT films by blending with poly (ethylene glycol)(PEG) without the need for additional polar solvent additives.[6] These initial studies strongly suggest that the addition of a polar media to P3HT can be used to tune its optical absorption and emission line shapes. However, the origin of these changes in optical properties and how much they can be manipulated in a controlled fashion have yet to be demonstrated rigorously. Here, we demonstrate that blending conjugated polymer systems with PEO strongly red-shifts the optical absorption of a range of conjugated polymers, including P3HT, the liquid-crystalline poly [2, 5-bis (3-tetradecylthiophen-2-yl) thieno [3, 2-b] thiophene](pBTTT), the donor-acceptor material poly [(9, 9-dioctylfluorenyl-2, 7-diyl)-alt-(4, 7-bis (3-hexylthiophen-5-yl)-2, 1, 3-benzo thiadiazole-2′, 2′′-diyl](F8TBT), and light-emitting polymers such as poly (2-methoxy-5-(3′, 7′-dimethyloctyloxy)-1, 4-phenylenevinylene (MDMO-PPV) and poly (9, 9-di-n-octylfluorenyl-2, 7-diyl (PFO), in their solid state. We will show that this shift very likely is due to the planarization of the conjugated polymers’ backbone in the presence of …