Optical Pumping of Poly(3-hexylthiophene) Singlet Excitons Induces Charge Carrier Generation.
Optical Pumping of Poly(3-hexylthiophene) Singlet Excitons Induces Charge Carrier Generation.
复制标题
聚（3-己基噻吩）单线态激子的光泵浦诱导载流子生成。
DOI：
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发表时间：
2014
影响因子：
5.7
通讯作者：
Tak W. Kee
中科院分区：
文献类型：
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作者：
Patrick C. Tapping;Tak W. Kee
聚（3-己基噻吩）（P3HT）的高能激子动力学由扭转弛豫和激子解离形成自由载流子组成。在这项工作中，我们使用泵推探针飞秒瞬态吸收光谱来研究溶液中 P3HT 的高激发态。 P3HT 激子使用泵浦脉冲 (400 nm) 生成，并在使用推脉冲（900 或 1200 nm）重新激发之前松弛到最低激发态，产生高能激子，以亚皮秒 (0.16 ps) 和皮秒 (2.4 ps) 时间常数衰减回到原始激发态。这些动力学与 P3HT 扭转松弛一致，其中 0.16 ps 时间常数分配给超快惯性扭转松弛。此外，信号表现出不完全恢复，表明由于推动脉冲的激发，高能激子解离形成电荷载流子。我们的分析表明载流子的形成率为 11%。
The dynamics of high-energy excitons of poly(3-hexylthiophene) (P3HT) are shown to consist of torsional relaxation and exciton dissociation to form free carriers. In this work, we use pump-push-probe femtosecond transient absorption spectroscopy to study the highly excited states of P3HT in solution. P3HT excitons are generated using a pump pulse (400 nm) and allowed to relax to the lowest-lying excited state before re-excitation using a push pulse (900 or 1200 nm), producing high-energy excitons that decay back to the original excited state with both subpicosecond (0.16 ps) and picosecond (2.4 ps) time constants. These dynamics are consistent with P3HT torsional relaxation, with the 0.16 ps time constant assigned to ultrafast inertial torsional relaxation. Additionally, the signal exhibits an incomplete recovery, indicating dissociation of high-energy excitons to form charge carriers due to excitation by the push pulse. Our analysis indicates that charge carriers are formed with a yield of 11%.