激子旋转弛豫对低掺杂卟啉侧链聚合物荧光衰变过程的影响

Effect of exciton rotational relaxation on luminescence decay of low-doped porphyrin side-chain polymers

利用激子旋转扩散理论研究了一类低掺杂卟啉侧链聚合物中卟啉侧链基团的旋转对其发光动力学过程的影响.研究表明,卟啉侧链基团的旋转行为是导致激发态无辐射能量弛豫的重要途径.基团旋转越容易,能量弛豫速度越快,这可导致一个快速的荧光衰变动力学过程.在卟啉低掺杂浓度和聚合物分子链间距离较大的情况下,卟啉侧链基团的旋转成为影响荧光寿命和发光效率的主要因素.对实验测得的两种样品的荧光弛豫过程进行了拟合,理论结果与实验结果符合较好.

Effect of rotational motion of porphyrin molecules on the luminescence dynamic of low-doped porphyrin side-chain polymers has been studied by using the theory of exciton rotational diffusion.It is shown that the rotational motion of porphyrin molecules is an important way that induces the nonradiative relaxation of excitons.The more easily porphyrins rotate,the more rapidly energy decays,therefore,the faster the luminescence decay process.In the case of low doping concentration of porphyrins and long interchain distance,the rotational motion of porphyrin molecules is the main reason of fast luminescence decay and low luminescence efficiency.The transient luminescence relaxation processes of two kinds of polymers were fitted with the theoretical expression,the theoretical analysis are in good agreement with the experimental results.