标题： 三重态在聚合物发光二极管发光机制中的作用 显示英文标题

标题： The role of triplet states in the emission mechanism of polymer light-emitting diodes

摘要： 聚芴（PF）基发光二极管（LED）的蓝光发射已知会由于低能绿光发射而退化，迄今为止，这一直被认为是氧化缺陷所致。 通过研究在氧气和惰性气氛中存在的乙基-己基取代的PF LED的电致发光，并在聚合物中使用痕量的顺磁杂质（PM），我们表明三重态在低能发射机制中起主要作用。 我们的时域多体研究表明，在存在PM的情况下，电子-空穴复合过程中三重态形成的截面很大，并且存在从激发单重态到三重态的系间窜跃。 显示英文摘要

摘要： The blue emission of polyfluorene (PF) based light-emitting diodes (LEDs) is known to degrade due to a low energy green emission, which hitherto has been attributed to oxidative defects. By studying the electroluminescence from ethyl-hexyl substituted PF LEDs in the presence of oxygen and in an inert atmosphere, and by using trace quantities of paramagnetic impurities (PM) in the polymer, we show that the triplet states play a major role in the low energy emission mechanism. Our time-dependent many-body studies show that there is a large cross-section for the triplet formation in the electron-hole recombination process in presence of PM, and intersystem crossing from excited singlet to triplet states.