Disilanyl Double-Pillared Bisanthracene: A Bipolar Carrier Transport Material for Organic Light-Emitting Diode Devices
Disilanyl Double-Pillared Bisanthracene: A Bipolar Carrier Transport Material for Organic Light-Emitting Diode Devices
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DOI：
10.1002/anie.201002432
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发表时间：
2010-01-01
影响因子：
16.6
通讯作者：
Isobe, Hiroyuki
中科院分区：
文献类型：
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作者：
Nakanishi, Waka;Hitosugi, Shunpei;Isobe, Hiroyuki
第一种直流电致发光材料蒽是有机电子学的基石分子。[1]关于蒽单晶电致发光的第一篇报道证明了有机分子作为发射材料以及空穴和电子传输材料的潜在用途。[2]蒽的真空沉积也为在低驱动电压下工作的薄膜器件铺平了道路（约1000伏）。30 V），尽管量子效率较低（约为30 V）。0.05%）和低衬底温度（约. 508C）。[3]然而，该分子很快被用于空穴传输层（HTL）的芳基胺衍生物，如N，N ′-二苯基-N，N ′-双（bis（1-萘基）-1，1 '-联苯-4，4 '-二胺（α-NPD）和tris在发现层状有机发光二极管（OLED）之后，用于电子传输层（ETL）的（8-羟基喹啉）铝（Alq 3）具有上级性能和稳定性。[4，5]虽然用于发射层（EML）的几种衍生物通过在9-和10-位上改变官能团而积累，[6]蒽衍生物作为层状OLED中的载流子传输材料的进一步应用很少被探索，[7]尽管对这些材料用于薄膜有机场效应晶体管（OFFET）的兴趣重新燃起。[8]我们在此报告的设计和合成的蒽衍生物，二硅烷基双柱撑双蒽（SiDPBA，1，方案1），它有效地作为一个双极载流子传输材料在OLED中的功能。蒽衍生物SiDPBA的设计没有引入为HTL和ETL材料建立的结构基序[7]，并且在一锅法中由1，8-二碘蒽合成（2;方案1）。因此，2在锂-卤素交换反应中使用叔丁基锂进行锂化，随后使用1，2-二氯四甲基二硅烷进行甲硅烷基化，得到SiDPBA。低聚副产物通过用乙醚洗涤而容易地除去，并且以50%的产率获得作为分析纯物质的所需化合物，而无需求助于柱色谱法。产物是单一异构体，蒽单元的反几何结构通过X射线晶体学分析揭示（见下文）。我们没有检测到另一种可能的同分异构体。该合成方法可用于克级制备。[9]SiDPBA的台阶状结构通过单晶的X射线衍射分析明确地建立。[10]如图1a所示，Cipso-Si-Si-Cipso部分的反周面排列以反平行方式定位两个相邻的蒽平面（另见支持信息中的表S2和S3）。SiSiSi单键和蒽平面之间的扭转角在61-738的范围内，这导致有利的σSiSi-π共轭（见下文）。[11]这些分子以类似于未取代的蒽的面对面的分子间接触堆积。这种排列在晶体中产生了分子间接触的二维网络，尽管分子独特的阶梯状形状扭曲了堆积，阻碍了典型人字形图案的形成（图1b）。
The first direct-current electroluminescent material, anthracene, has been the cornerstone molecule for organic electronics.[1] The first reports on the electroluminescence with single crystals of anthracene demonstrated the potential use of organic molecules as emission materials as well as hole-and electron-transport materials.[2] Vacuum deposition of anthracene also paved the way for thin-film devices functioning at a low driving voltage (ca. 30V) albeit at a low quantum efficiency (ca. 0.05%) and low substrate temperature (ca. À508C).[3] However, the molecule was quickly replaced with aryl amine derivatives for the hole-transport layer (HTL), such as N, N’-diphenyl-N, N’-bis (1-naphthyl)-1, 1’-biphenyl-4, 4’-diamine (α-NPD) and with tris (8-hydroxyquinoline) aluminum (Alq3) for the electron-transport layer (ETL) after the discovery of layered organic light-emitting diodes (OLEDs) with superior performance and stability.[4, 5] Although several derivatives for the emission layer (EML) were accumulated by varying functional groups at the 9-and 10-positions,[6] the further application of anthracene derivatives as carrier transport materials in layered OLEDs has been rarely explored,[7] despite the renewed interest in these materials for thin-film organic field-effect transistors (OFETs).[8] We report herein on the design and synthesis of an anthracene derivative, disilanyl double-pillared bisanthracene(SiDPBA, 1, Scheme 1), which effectively functions as a bipolar carrier transport material in OLEDs. The device performance using SiDPBA as both an HTL and ETL material is reasonably high and highlights a new strategy for the molecular design of organic electronic materials.The anthracene derivative SiDPBA was designed without importing structural motifs established for HTL and ETL materials [7] and was synthesized in a one-pot procedure from 1, 8-diiodoanthracene (2; Scheme 1). Thus, 2 was lithiated in the lithium–halogen exchange reaction using tert-butyllithium and was subsequently silylated using 1, 2-dichlorotetramethyldisilane to give SiDPBA. Oligomeric byproducts were easily removed by washing with diethyl ether, and the desired compound was obtained in 50% yield as an analytically pure material without recourse to column chromatography. The product was a single isomer, and the anti geometry of the anthracene units was revealed by X-ray crystallographic analysis (see below). We did not detect the other possible isomer with syn geometry. The synthesis method is feasible for gram-scale preparation.[9] The step-like structure of SiDPBA was established unequivocally by X-ray diffraction analysis of a single crystal.[10] As shown in Figure 1a, the antiperiplanar alignment of the Cipso-Si-Si-Cipso moiety positions two adjacent anthracene planes in an antiparallel manner (see also Tables S2 and S3 in the Supporting Information). The torsion angles between the SiÀSi single bond and the anthracene plane are in the range 61–738, which results in a favorable σSiSi–π conjugation (see below).[11] The molecules are packed with face-to-edge intermolecular contacts similar to unsubstituted anthracene. The arrangement yields a two-dimensional network of intermolecular contacts in the crystal, although the unique step-like shape of the molecule distorts the packing and hinders the formation of typical herringbone motifs (Figure 1b).