Electrochemical
doping is a promising strategy to dope halide perovskites
without introducing impurities into the lattice. However, n-type doping
of halide perovskites remains challenging due to intrinsically limited
electrochemical stability. Herein, we report electrochemically n-doped
CsPbBr3 nanocrystal (NC) films within electrochemically
stable potential windows (−0.9–0.5 V vs Ag/AgNO3). Compared to bulk films with limited accessible surface
area for cation charge compensation, NC films show more efficient
n-doping properties due to their porous nature. Electrochemically
doped NC films exhibit Fermi level shifts, confirmed via electrochemical
measurements, vacuum-Kelvin probe contact potential difference, and
photoelectron spectroscopy. As a result, in situ conductivity
measurements show increases when films are p- or n-doped. Furthermore,
n-doped films show a photoluminescence intensity increase. Given that
we remain within the electrochemically stable window, we suspect this
is due to an alleviation of electron traps, likely a result of altering
the charge state of the interstitial Br population.