Investigation of the crossover between spin orbit and hyperfine driven electron spin relaxation

Organic semiconductors (OSCs) are enabling flexible, large-area optoelectronic devices, such as organic light-emitting diodes (OLEDs), transistors and solar cells. OSCs can be simple to process, stable and non-toxic, and the variety of possible molecular designs is enormous. Due to their long spin lifetimes, carbon-based materials could also have an impact on spintronics. Both spin orbit (SO) interaction and hyperfine (HF) interaction have been used separately to explain the magnetoresistance and spin diffusion length in spin valves of the same organic material. It is therefore very important to understand the mechanisms of spin relaxation in OSCs. Here, we propose to use muons to directly probe the crossover between SO and HF, and compare the results directly to g-shifts in electron paramagnetic resonance and theoretical models.

有机半导体（OSCs）正推动柔性、大面积光电器件的发展，例如有机发光二极管（OLEDs）、晶体管及太阳能电池。OSCs具有工艺简单、稳定且无毒的特点，其潜在分子设计的多样性极为丰富。由于其自旋寿命较长，碳基材料也可能在自旋电子学领域产生影响。自旋轨道（SO）相互作用与超精细（HF）相互作用均已被分别用于解释同一有机材料自旋阀中的磁电阻及自旋扩散长度现象。因此，理解OSCs中的自旋弛豫机制至关重要。在此，我们提出利用缪子直接探测SO与HF之间的交叉效应，并将结果直接与电子顺磁共振中的g因子位移及理论模型进行对比。