Tuning of spin-orbit coupling in metal-free conjugated polymers by structural conformation

Giant spin pumping at the ferromagnet (permalloy) – organic semiconductor (perylene diimide) interface

“…The PDI which is deposited using spin coating has shown a disordered arrangement of J-aggregates and it has inherent higher charge carrier mobility as compared to DNTT, 36 P 3 MT and P 3 HT4. 30 We believe that the combination of both these factors that are mentioned above may be attributed to the enhancement of spin pumping into PDI from Py. Our results suggest that PDI can be used as non-magnetic layers for spin injection from ferromagnetic layers irrespective of the resistance mismatch.…”

“…[23][24][25][26][27][28][29] Moreover, the ease of tunability of SOC compared to the inorganic materials makes OSCs potential materials to be used in spin pumping experiments. 30 So far, various conjugated polymers and few small molecules were explored for the spin injection process through ISHE measurements and achieved spin relaxation time and spin diffusion lengths as high as 10 ms and 1.2 mm, respectively. 12,23,28,[31][32][33] Whereas, spin pumping is an effective method for the generation and injection of pure spin current (J s ) at the ferromagnet/non-magnet (FM/NM) interfaces.…”

“…36 More recently, Vetter et al have used twisted three ploy (3alkylthiophene) polymers to tune the SOC via structural conformation by controlling the conjugation lengths. 30 In this work, a so magnetic material Ni 80 Fe 20 (permalloy: Py) is chosen as FM acts as the spin source which enable efficient spin injection into the NM layers. 37 We have chosen perylene diimide (PDI) based small molecular OSC as a potential NM material.…”

“… 36 More recently, Vetter et al have used twisted three ploy (3-alkylthiophene) polymers to tune the SOC via structural conformation by controlling the conjugation lengths. 30 …”

Hopping-Dominated Spin Transport in Unintentionally Doped Organic Semiconductors

“…One is based on carriers hopping transport with the movement of carriers carrying opposite spins in opposite directions, and the other via exchange coupling between carriers without the simultaneous charge flow. − Since the spin current is carried by polarons in OSCs which can be delocalized over ∼1 nm length scale, at high carrier densities, the delocalization of the polaron may activate an exchange coupling which enables the carriers transfer their spin alignment to adjacent sites without a physical hopping process. However, at low carrier densities, this process cannot take place because of weak spin exchange coupling. , According to our previous studies, the critical carrier density of active direct exchange coupling is equal to 8 × 10 17 cm –3 . Surprisingly, the PSC transport has recently been observed in OSCs with much lower carrier density than this critical value .…”