Fig. 1: Magneto-photocurrent and coherent spin mixing principle.
a Schematic illustration for the photophysics of an organic donor-acceptor bulk heterojunction. b–g The pictorial illustration for the coherent spin mixing. h Schematic diagram for the magneto-photocurrent setup. i The expeimental result of the room temperature magneto-photocurrent for the organic solar cell comprising ITO(glass)/ZnO/PBDB-T:ITIC/MoO3/A (black circles). We used three different models for testings (red/green/blue solid lines). The photoexcitation wavelength and power density was 635 nm and 240 mW/cm2 respectively. The symbolic notations are defined by: the singlet exciton recombination rate \(({r}_{S})\), the triplet exciton recombination rate \(({r}_{T})\), the singlet polaron pair dissociation rate \(({k}_{S})\) and fusion rate \(({f}_{S})\) at single charge transfer states \(({\left({\rm{CTS}}\right)}^{{\rm{S}}})\), the triplet polaron pair dissociation rate \(({k}_{T})\) and fusion rate \(({f}_{T})\) at triplet charge transfer states \(({\left({\rm{CTS}}\right)}^{{\rm{T}}})\), \({\omega }_{S-T}\) is the spin mixing rate or the interconversion rate of \({({\rm{CTS}})}^{{\rm{S}}}\) and \({({\rm{CTS}})}^{{\rm{T}}}\). The singlet and triplet polaron pair decay rates are defined by \({\gamma }_{S}\) \(({\rm{i}}.{\rm{e}}.,\,{\gamma }_{S}={k}_{S}+{f}_{S})\) and \({\gamma }_{T}\) \(({\rm{i}}.{\rm{e}}.,\,{\gamma }_{T}={k}_{T}+{f}_{T})\) respectively. \({\vec{S}}_{1}\) and \({\vec{S}}_{2}\) denote two spin vectors. The hyperfine field 1 and 2 are \({\vec{B}}_{{hf}1}\) and \({\vec{B}}_{{hf}2}\) respectively. The spin-orbit coupling field 1 and 2 are \({\vec{B}}_{{SOC}1}\) and \({\vec{B}}_{{SOC}2}\) respectively.
