High field magneto-photocurrent in organic bulk hetero-junction photo-voltaic cells

• rrP3HT/PCBM bulk hetero-junction photo-voltaic cell produced photocurrent (PC) upon 470 nm LED irradiation.
• The resulting photocurrent were studied using high (up to 8.5 T) magnetic field (MPC).
• The observed high field MPC is attributed to a spin-mixing mechanism caused by the difference in the donor-acceptor g-factors.
• The non-saturating MPC response at high field is interpreted as due to charge transfer excitons with in the sub-nanosecond lifetime.
• The MPC response profile is highly non-Lorentzian due to a dispersive decay mechanism.

We analyze the high field (up to 8.5 T) non-saturating magneto-photocurrent (MPC) in rrP3HT/PCBM bulk hetero-junction photo-voltaic cells. We attribute the observed high field MPC at room temperature to a spin-mixing mechanism caused by the difference in the donor-acceptor g-factors. The non-saturating MPC response at high field indicates that there exist charge transfer excitons with lifetime in the sub-nanosecond time domain. The MPC response profile is highly non-Lorentzian. We explain this non-Lorentzian shape by a dispersive decay mechanism that originates due to a broad distribution of charge transfer exciton lifetimes.

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