Effect of Charge Localization on the Effective Hyperfine Interaction in Organic Semiconducting Polymers
Effect of Charge Localization on the Effective Hyperfine Interaction in Organic Semiconducting Polymers
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DOI：
10.1103/physrevlett.120.086602
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发表时间：
2018-02-22
影响因子：
8.6
通讯作者：
Nguyen, Tho D.
中科院分区：
文献类型：
--
作者：
Geng, Rugang;Subedi, Ram C.;Nguyen, Tho D.
超精细相互作用（HFI），起源于电荷载流子和核之间的自旋耦合，已被证明强烈影响有机半导体中局域电荷的自旋动力学。然而，在有机薄膜中的HFI强度的电荷本地化的作用还没有实验研究。本文研究了区域规则聚3-己基噻吩（P3 HT）中空穴的有效HFI与1/N-0.5成正比的统计关系假设，其中N是空穴波函数包络内的随机核自旋数。首先，通过研究由同位素标记的P3 HT制成的空穴器件中的磁导，我们验证了HFI确实是P3 HT中占主导地位的自旋相互作用。其次，假设空穴完全离域的P3 HT多晶域，HFI的强度实验证明是成比例的1/N-0.52的统计关系非常吻合。第三，由于电子的更强的局域化，P3 HT中电子的HFI比空穴的HFI强约3倍。最后，发现有机发光二极管中的有效HFI是有效电子和空穴HFI的叠加。这种统计关系通常可以应用于其他半导体聚合物。这封信可能为有机光电子学、化学反应动力学和生物学中的磁感受提供巨大的好处。
Hyperfine interaction (HFI), originating from the coupling between spins of charge carriers and nuclei, has been demonstrated to strongly influence the spin dynamics of localized charges in organic semiconductors. Nevertheless, the role of charge localization on the HFI strength in organic thin films has not yet been experimentally investigated. In this study, the statistical relation hypothesis that the effective HFI of holes in regioregular poly(3-hexylthiophene) (P3HT) is proportional to 1/N-0.5 has been examined, where N is the number of the random nuclear spins within the envelope of the hole wave function. First, by studying magnetoconductance in hole-only devices made by isotope-labeled P3HT we verify that HFI is indeed the dominant spin interaction in P3HT. Second, assuming that holes delocalize fully over the P3HT polycrystalline domain, the strength of HFI is experimentally demonstrated to be proportional to 1/N-0.52 in excellent agreement with the statistical relation. Third, the HFI of electrons in P3HT is about 3 times stronger than that of holes due to the stronger localization of the electrons. Finally, the effective HFI in organic light emitting diodes is found to be a superposition of effective electron and hole HFI. Such a statistical relation may be generally applied to other semiconducting polymers. This Letter may provide great benefits for organic optoelectronics, chemical reaction kinetics, and magnetoreception in biology.