Yao Jingwen, Dong Shou-Cheng, Tam Bryan Siu Ting, Tang Ching W
Institute for Advanced Study, Hong Kong University of Science Technology, Clear Water Bay, Kowloon, Hong Kong.
State Key Laboratory of Advanced Displays and Optoelectronics Technologies, Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
ACS Appl Mater Interfaces. 2023 Feb 8;15(5):7255-7262. doi: 10.1021/acsami.2c22882. Epub 2023 Jan 26.
Significant lifetime enhancement, up to an eight-fold increase in T, has been demonstrated in blue organic light-emitting diode (OLED) devices through the deuteration of host and hole transport materials. We observed a progressive increase in T using a series of anthracene-based hydrocarbon hosts with incremental deuteration in the emitting layer. In addition, we realized further lifetime improvement using a deuterated hole-transport layer along with the deuterated emitting layer. To elucidate the deuteration effects, we utilized laser desorption/ionization-time-of-flight (LDI-TOF) mass spectrometry for in situ UV irradiation to induce photodegradation and immediate chemical analysis of the resultant photodegradation species. Adducts between the host and moieties from transport materials were identified in UV-degraded films comprising a mixture of host and transport materials, indicating that similar species could be produced in OLED devices using these materials. Deuteration, in effect, mediated the formation of these adduct species, presumably electroluminescence quenchers, and thus improved the device lifetime. An approximate agreement was obtained between the kinetic isotope effect of the photodegradation reactions and the enhancement in device lifetime with deuteration.
通过对主体材料和空穴传输材料进行氘代，蓝色有机发光二极管（OLED）器件的寿命得到了显著提高，T值提高了八倍。我们使用了一系列基于蒽的碳氢化合物主体材料，在发光层中进行增量氘代，观察到T值逐渐增加。此外，我们通过使用氘代空穴传输层和氘代发光层，进一步提高了器件寿命。为了阐明氘代效应，我们利用激光解吸/电离飞行时间（LDI-TOF）质谱对原位紫外辐射进行诱导光降解，并对产生的光降解产物进行即时化学分析。在包含主体材料和传输材料混合物的紫外降解薄膜中，鉴定出了主体材料与传输材料部分之间的加合物，这表明在使用这些材料的OLED器件中可能会产生类似的物质。实际上，氘代介导了这些加合物的形成，推测这些加合物是电致发光猝灭剂，从而提高了器件寿命。光降解反应的动力学同位素效应与氘代对器件寿命的提高之间获得了近似的一致性。
