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.