Passivating Lead Halide Perovskites Using Pyridinium Salts with Superhalogen Atoms

Passivating
lead halide perovskites using pyridinium salts has
attracted enormous attention, but the excellent surface passivation
of the halide perovskites has not been achieved by using only a pyridinium
salt until now. Herein, passivating the (001) planes of the cubic
CsPbI3, CH3NH3PbI3, and
NH2CHNH2PbI3 perovskites using the
pyridinium salts of C5NH6X (X = Cl, Br, I, PF6, ClO4, or BF4) is systematically studied
by high-throughput first-principle calculations and ab initio molecular
dynamics simulations. The results show that the excellent surface
passivation of the three perovskites is achieved by the pyridinium
salt of C5NH6BF4 (i.e., shallow level,
negative formation energy, unchanged band-edge construction, and stable
dynamics property are obtained for the three passivated perovskites),
which strongly imply that their devices can show excellent performances,
such as long-term stability, low ion migration, and high efficiency.
However, the C5NH6ClO4 and C5NH6PF6 pyridinium salts are only profitable
for passivating the (001) PbI2 plane of the three perovskites,
and other C5NH6X pyridinium salts have adverse
effects.