Generation and recombination kinetics of optical excitations in poly(3-dodecylthienylenevinylene) with controlled regioregularity.
Generation and recombination kinetics of optical excitations in poly(3-dodecylthienylenevinylene) with controlled regioregularity.
复制标题
具有受控区域规整性的聚（3-十二烷基噻吩乙烯撑）中光激发的产生和重组动力学。
DOI：
10.1021/jp2066666
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Cheng Zhang
中科院分区：
文献类型：
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作者：
E. Lafalce;Xiaomei Jiang;Cheng Zhang
已知π-共辄聚合物中的区域规整性对固态下的链组织具有期望的影响，从而导致电子器件应用的改进的特性。本文采用稳态光诱导吸收（PIA）、掺杂诱导吸收（DIA）、热调制吸收（TMA）、宽光谱范围的光致发光（PL）技术以及掠入射X射线衍射（GIXRD）技术，研究了一系列新型π共轭聚合物，即聚（3-十二烷基噻吩亚乙烯基）的可控区域规整性（PTV-CR）的光物理性质。PTV-CR具有从最无规PTV-5：5到规则PTV-0：10的1.65 - 1.70 eV的低带隙。我们已经发现，区域规整性影响的PTV-CR的光学性能在不同的方式比在充分研究的情况下的聚（3-烷基噻吩）。我们发现，即使是最随机的PTV-5：5显示亚微米晶体秩序，并没有区域规则性和堆积性之间的相关性。我们发现PTV是本征暗的，这是由于1B（u）和2A（g）激子的顺序相反，其PL量子效率在10（-5）到2 × 10（-4）之间。光谱数据证实了长寿命中性（三重态）和带电（极化子）激发的存在，因此PTV是一种独特的非简并基态π共轭聚合物，本质上不发光。这种长寿命激发的复合机制和寿命的研究，通过泵浦强度和泵浦频率的依赖关系，以及样品的温度依赖性。增加区域规整性被认为是减少这些薄膜的热响应性和系统间的交叉。新的，这些效果和它们的影响使用PTV衍生物的光伏应用的链内字符进行了讨论。
Regioregularity in π-conjugated polymers is known to have desirable effects on chain organization in the solid state leading to improved characteristics for electronic device applications. In this report, we studied the photophysics of a new series of π-conjugated polymers, namely, poly(3-dodecylthienylenevinylene), with controlled regioregularity (PTV-CR), using the steady state photoinduced absorption (PIA), doping-induced absorption (DIA), thermally modulated absorption (TMA), and photoluminescence (PL) techniques in a broad spectral range, as well as Grazing incidence X-ray diffraction (GIXRD). PTV-CR has a low band gap of 1.65-1.70 eV from the most random PTV-5:5 to regular PTV-0:10. We have found that regioregularity affects optical properties of PTV-CR in different ways than in the case of well-studied poly(3-alkylthiophene). We discovered that even the most random PTV-5:5 shows submicrometer crystalline order, and there is no correlation between regioregularity and crystallinality. We found that PTV is intrinsically dark due to the reverse order of 1B(u) and 2A(g) excitons, with PL quantum efficiency ranging from 10(-5) to 2 × 10(-4). Spectroscopic data confirm the existence of long-lived neutral (triplets) and charged (polaron) excitations, and thus PTV is a unique nondegenerate ground state π-conjugated polymer which is intrinsically nonluminescent. The recombination mechanism and lifetime of such long-lived excitations are investigated through the pump intensity and pump frequency dependencies as well as temperature dependence of the sample. Increasing regioregularity is seen to reduce the thermal responsivity and intersystem crossing in these films. The novel, intrachain character of these effects and their implications for use of PTV derivatives for photovoltaic application are discussed.