The current–voltage
hysteresis, as well as the performance
instability of perovskite solar cells (PSCs) under a working condition,
is serving as the major obstacle toward their commercialization while
the exact fundamental mechanisms to these issues are still in debate.
In this study, we investigated the slow variation of photogenerated
carrier dynamics in a (FAPbI3)0.85(MAPbBr3)0.15 perovskite interface under continuous illumination.
Different response behaviors of carrier dynamics in the perovskite
interfaces with and without the hole transport layer, Spiro-OMeTAD
(Spiro), were systematically studied by time-dependent, steady-state,
and time-resolved photoluminescence. It was demonstrated that a light-induced
defect curing process is dominantly responsible for the carrier dynamics
evolution for the perovskite interface without Spiro, whereas both
defect curing process and mobile ion migration should be accounted
for the dynamic response of the perovskite interface contact with
Spiro. When contacted with Spiro, the energy band curvature evolution
in the perovskite interface induced by ion migration would decrease
the hole transfer rate from the perovskite interface to Spiro upon
illumination. This research work can faithfully highlight the strong
correlation of slow photoresponse behaviors of the perovskite interface
with both light-induced defect curing and ion migration processes,
providing novel implications into the physical mechanism for the slow
variation of PSC performances under a working condition.