Dipole evoked hole-transporting material p-doping by utilizing organic salt for perovskite solar cells

Highlights: • Phenylamine cation based dopant is developed on doping of Spiro-OMeTAD. • Newly understanding on p-doping mechanism for Spiro-OMeTAD. • Defects orbits shift on perovskite traps passivation by p-dopant. • High efficiency of PSCs based on single dopant for Spiro-OMeTAD. • PSCs show high stability which near 90% of initial PCE after aging 40 days. Herein, a phenylamine cation based dopant (PHC) is demonstrated as the efficient and stable Spiro-OMeTAD single dopant within PSCs where the [Spiro-OMeTAD]• ⁺ radical is primarily generated by intermolecular dipole moment derived charge transfer. Beyond the prominent advantages of PHC in hydrophobic and larger van der Waals radius of phenylamine cation as compared to Li⁺ ion which is favorable for stability of PSCs, the detailed findings reveals that it could also convert deep trap states to shallow tarp states via orbital shifting and hybridization for perovskite, in addition supplies the populated states near valence band and reinforced interface build-in filed (E_bi) which extremely restrain non-radiative recombination and enhances the carriers transfer with decreased barriers for hetero-junction interface. As a result, the efficiency of devices reaches 21.34% with ultrahigh FF of 80.24% versus 20.66% for the device based on Li-TFSI/t-BP bi-dopants which is the best efficiency of PSCs based on single dopant. Besides, the PHC based PSCs also displays much higher long-term stability up to 40 days under air ambient without encapsulation.