(1-Naphthyl)phenylamino functionalized three-coordinate organoboron compounds: syntheses, structures, and applications in OLEDs
作者:Wen Li Jia、Mark J. Moran、Yan-Yan Yuan、Zheng Hong Lu、Suning Wang
DOI:10.1039/b506840a
日期:——
New three-coordinate organoboron compounds functionalized by a (1-naphthyl)phenylamino group, B(mes)2(dbp-NPB)
(1), B(db-NPB)3
(2), and B(dbp-NPB)3
(3), have been synthesized. A variable temperature 1H NMR study showed that the aryl groups around the boron center in these compounds have a rotation barrier ∼70 kJ mol−1. The new boron compounds are amorphous solids with Tg being 110 °C, 171 °C and 173 °C, respectively. The electronic properties of the new boron compounds were investigated by cyclic voltammetry and UV–visible spectroscopy. All three boron compounds are blue emitters in the solid state. In solution the emission spectra of the boron compounds shift toward a longer wavelength with increasing solvent polarity. In CH2Cl2, the emission quantum efficiency of the three compounds was determined to be 0.22, 0.27 and 0.23, respectively. Several series of electroluminescent (EL) devices where compounds 1–3 are used as either an emitter/electron transport material, a hole transport material, or a hole injection material have been fabricated and their performance has been compared to the corresponding devices of BNPB, a previously investigated molecule, NPB, a commonly used hole transport material, and CuPc, a commonly used hole injection material. The EL results indicate that the new boron compounds are not suitable as emitters/electron transport materials, but they are promising as hole transport and hole injection materials in EL devices.
新合成了三种含(1-萘基)苯胺基团的三坐标有机硼化合物,分别为 B(mes)2(dbp-NPB) (1)、B(db-NPB)3 (2) 和 B(dbp-NPB)3 (3)。变温 1H NMR 研究表明,这些化合物中围绕硼中心的芳基旋转势垒约为 70 kJ mol−1。新硼化合物为非晶固体,玻璃化转变温度 Tg 分别为 110 °C、171 °C 和 173 °C。通过循环伏安法和紫外-可见光谱研究了新硼化合物的电子性质。三种硼化合物在固态下均为蓝色发光体。在溶液中,随着溶剂极性的增加,硼化合物的发射光谱向长波长方向移动。在 CH2Cl2 中,三种化合物的发射量子效率分别为 0.22、0.27 和 0.23。制备了多系列电致发光(EL)器件,其中化合物 1-3 分别用作发射/电子传输材料、空穴传输材料或空穴注入材料,并将其性能与之前研究的分子 BNPB、常用的空穴传输材料 NPB 和常用的空穴注入材料 CuPc 相应的器件进行了比较。EL 结果表明,新硼化合物不适合作发射/电子传输材料,但它们作为 EL 器件中的空穴传输和空穴注入材料具有潜在应用前景。