Department of Applied Chemistry, Graduate School of Engineering, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan.
Center for Molecular Systems (CMS), 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan.
Nat Commun. 2023 Mar 1;14(1):1056. doi: 10.1038/s41467-023-36698-4.
Singlet fission (SF), converting a singlet excited state into a spin-correlated triplet-pair state, is an effective way to generate a spin quintet state in organic materials. Although its application to photovoltaics as an exciton multiplier has been extensively studied, the use of its unique spin degree of freedom has been largely unexplored. Here, we demonstrate that the spin polarization of the quintet multiexcitons generated by SF improves the sensitivity of magnetic resonance of water molecules through dynamic nuclear polarization (DNP). We form supramolecular assemblies of a few pentacene chromophores and use SF-born quintet spins to achieve DNP of water-glycerol, the most basic biological matrix, as evidenced by the dependence of nuclear polarization enhancement on magnetic field and microwave power. Our demonstration opens a use of SF as a polarized spin generator in bio-quantum technology.
单线态裂变（SF），即将单线态激发态转化为自旋关联的三重态对态，是在有机材料中产生自旋五重态的有效方法。尽管它作为激子倍增剂在光伏领域的应用已经得到了广泛的研究，但对其独特的自旋自由度的利用在很大程度上仍未得到探索。在这里，我们证明了通过动态核极化（DNP），SF 产生的五重态多激子的自旋极化提高了水分子磁共振的灵敏度。我们形成了几个并五苯发色团的超分子组装体，并利用 SF 产生的五重态自旋实现了水-甘油的 DNP，这是最基本的生物基质，这一点可以通过核极化增强对磁场和微波功率的依赖性来证明。我们的演示为 SF 作为生物量子技术中的极化自旋发生器开辟了新的应用前景。
