Coherent charge transport can occur in organic semiconductor crystals thanks to the highly periodic electrostatic potential—despite the weak van der Waals bonds. And as spin–orbit coupling is usually weak in organic materials, robust spin transport is expected, which is essential if they are to be exploited for spintronic applications. In such systems, momentum relaxation occurs via scattering events, which enables an intrinsic mobility to be defined for band-like charge transport, which is >10 cm² V⁻¹ s⁻¹. In contrast, there are relatively few experimental studies of the intrinsic spin relaxation for organic band-transport systems. Here, we demonstrate that the intrinsic spin relaxation in organic semiconductors is also caused by scattering events, with much less frequency than the momentum relaxation. Magnetotransport measurements and electron spin resonance spectroscopy consistently show a linear relationship between the two relaxation times over a wide temperature range, clearly manifesting the Elliott–Yafet type of spin relaxation mechanism. The coexistence of an ultra-long spin lifetime of milliseconds and the coherent band-like transport, resulting in a micrometre-scale spin diffusion length, constitutes a key step towards realizing spintronic devices based on organic single crystals.

尽管有较弱的范德华键，但由于高周期性静电势，有机半导体晶体中仍可能发生相干电荷传输。而且由于有机材料中自旋-轨道耦合通常较弱，因此有望实现强劲的自旋输运，这对于将其用于自旋电子学应用而言至关重要。在这样的系统中，动量弛豫通过散射事件发生，这使得能够为大于10 cm ²  V ^-1  s ^-1的带状电荷传输定义固有迁移率。相反，有机带传输系统的固有自旋弛豫的实验研究相对较少。在这里，我们证明有机半导体中的固有自旋弛豫也是由散射事件引起的，其频率远小于动量弛豫。磁传输测量和电子自旋共振光谱始终显示出在宽温度范围内两个弛豫时间之间的线性关系，清楚地表明了Elliott-Yafet类型的自旋弛豫机制。毫秒级超长自旋寿命与相干的带状传输并存，导致微米级的自旋扩散长度，是实现基于有机单晶的自旋电子器件的关键一步。