Wohlgenannt M, Jiang X M, Vardeny Z V, Janssen R A J
Department of Physics and Astronomy, The University of Iowa, Iowa City, Iowa 52242, USA.
Phys Rev Lett. 2002 May 13;88(19):197401. doi: 10.1103/PhysRevLett.88.197401. Epub 2002 Apr 25.
We have measured the ratio, r = sigma(S)/sigma(T) of the formation cross section, sigma of singlet and triplet excitons from polarons in pi-conjugated oligomer and polymer films, using a spectroscopic technique we developed recently. We discovered a universal relation between r and the conjugation length (CL): r(-1) depends linearly on CL-1, irrespective of the chain structure. Since r is directly related to the maximum possible electroluminescence quantum efficiency in organic light emitting diodes (OLED), our results indicate that polymers have an advantage over small molecules in OLED applications.
我们使用最近开发的一种光谱技术，测量了π共轭低聚物和聚合物薄膜中极化子形成单重态和三重态激子的截面σ的比值r = σ(S)/σ(T)。我们发现r与共轭长度（CL）之间存在一种普遍关系：r的倒数与CL的倒数呈线性关系，与链结构无关。由于r与有机发光二极管（OLED）中最大可能的电致发光量子效率直接相关，我们的结果表明，在OLED应用中，聚合物比小分子具有优势。
