Exploring mechanisms for generating spin-orbital coupling through donor–acceptor design to realize spin flipping in thermally activated delayed fluorescence

Abstract

Spin-orbital coupling effects and the underlying spin-dependent processes to achieve high-efficiency TADF are revealed based on magneto-optical studies.

Self-Stimulated Dissociation in Non-Fullerene Organic Bulk-Heterojunction Solar Cells

“…60,61 Second, the charge-transfer states possess both electrical and spin polarizations with internal electric-magnetic coupling, giving rise to a spin-orbital coupling, as shown in organic exciplex systems. 62 Third, an external magnetic field can change the singlet/triplet ratio in photoinduced dipoles through spin flipping. This leads to a magneto-capacitance phenomenon in dipolar polarization regime, because singlet and triplet photoinduced dipoles have different polarizations.…”

Intrinsic photogeneration of long-lived charges in a donor-orthogonal acceptor conjugated polymer

“…A signicant implication of this observation is that the slow 1 CT/ 3 CT equilibrium may be acting as a reservoir for charge carrier formation, enabling charge carriers to generate and exist in a pristine polymer long aer typically expected in standard conjugated polymers. While the existence of 1 CT/ 3 CT equilibria is not new in organic electronics materials, [58][59][60] this is, to our knowledge, the rst time it has been successfully combined with an orthogonal acceptor to enable long-lived charge carrier populations, particularly in the pristine material.…”

“…3c, d and 4b). PC 60 BM was chosen because it has been well-studied and its excited species transitions are known; 41,42 furthermore, its transient species have low oscillator strengths and thus the PCPDT-sFCN features will dominate. Fig.…”

Spin-orbital coupling and slow phonon effects enabled persistent photoluminescence in organic crystal under isomer doping

“…In general, magnetic field effects can be observed at low and high fields (<10 mT and >10 mT), when hyperfine interaction and SOC govern the singlet-triplet intersystem crossing, respectively 9,35,36 . The early studies in the 1970s showed that the delayed fluorescence in aromatic structures can exhibit magnetic field effects at the lower field (<10 mT) 37,38 .…”

“…In this scenario, it has been proposed that the triplets can directly recombine into phosphorescence or convert into singlets through the intersystem crossing, leading to persistent PL based on phosphorescence and delayed fluorescence. It should be noted that both phosphorescence and delayed fluorescence require a substantial spin-orbital coupling (SOC) to flip the spins of triplets toward either direct recombination or intersystem crossing 9,10 . Therefore, establishing a SOC becomes a critical issue to generate phosphorescence and delayed fluorescence toward realizing a persistent PL.…”