Four ultrahigh energy gap organosilicon compounds [diphenyldi(o-tolyl)silane (UGH1), p-bis(triphenylsilyl)benzene (UGH2), m-bis(triphenylsilyl)benzene (UGH3), and 9,9‘-spirobisilaanthracene (UGH4)] were employed as host materials in the emissive layer of electrophosphorescent organic light-emitting diodes (OLEDs). The high singlet (∼4.5 eV) and triplet (∼3.5 eV) energies associated with these materials effectively suppress both the electron and energy transfer quenching pathways between the emissive dopant and the host material, leading to deep blue phosphorescent devices with high (∼10%) external quantum efficiencies. Furthermore, by direct charge injection from the adjacent hole and electron transport layers onto the phosphor doped into the UGH matrix, exciton formation occurs directly on the dopant, thereby eliminating exchange energy losses characteristic of guest−host energy transfer. We discuss the material design, and present device data for OLEDs employing UGHs. Among the four host materials, UGH2 and UGH3 have higher quantum efficiencies than UGH1 when used in OLEDs. Rapid device degradation was observed for the UGH4-based device due to electro- and/or photooxidation of the diphenylmethane moiety in UGH4. In addition to showing that UGH materials can be used to fabricate efficient blue OLEDs, we demonstrate that very high device efficiencies can be achieved in structures where the dopant transports both charge and excitons.

中文翻译：

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深蓝色有机电致磷光器件中的超高能隙主体

四种超高能隙有机硅化合物[二苯基二（邻甲苯基）硅烷（UGH1），对-双（三苯基甲硅烷基）苯（UGH2），m-双（三苯基甲硅烷基）苯（UGH3）和9,9'-螺双双蒽蒽（UGH4）]被用作电致磷光有机发光二极管（OLED）的发射层的主体材料。与这些材料相关的高单重态（〜4.5 eV）和三重态（〜3.5 eV）能量有效地抑制了发射性掺杂剂和主体材料之间的电子和能量转移猝灭路径，从而导致了具有高（〜10）的深蓝色磷光器件％）外部量子效率。此外，通过从相邻的空穴和电子传输层直接电荷注入到掺杂到UGH基质中的磷光体上，激子的形成直接发生在掺杂剂上，从而消除了客体-主体能量转移的交换能量损失。我们讨论材料设计，并提供采用UGH的OLED的设备数据。在四种主体材料中，用于OLED的UGH2和UGH3的量子效率高于UGH1。对于基于UGH4的设备，由于UGH4中二苯甲烷部分的电氧化和/或光氧化，导致设备快速降解。除了表明UGH材料可用于制造高效的蓝色OLED之外，我们还证明了在掺杂剂既能传输电荷又能吸收激子的结构中，可以实现很高的器件效率。