posted on 2022-01-06, 10:13authored byYuqin Zou, Shuai Yuan, Ali Buyruk, Johanna Eichhorn, Shanshan Yin, Manuel A. Reus, Tianxiao Xiao, Shambhavi Pratap, Suzhe Liang, Christian L. Weindl, Wei Chen, Cheng Mu, Ian D. Sharp, Tayebeh Ameri, Matthias Schwartzkopf, Stephan V. Roth, Peter Müller-Buschbaum
Crystal orientations are closely
related to the behavior of photogenerated
charge carriers and are vital for controlling the optoelectronic properties
of perovskite solar cells. Herein, we propose a facile approach to
reveal the effect of lattice plane orientation distribution on the
charge carrier kinetics via constructing CsBr-doped mixed cation perovskite
phases. With grazing-incidence wide-angle X-ray scattering measurements,
we investigate the crystallographic properties of mixed perovskite
films at the microscopic scale and reveal the effect of the extrinsic
CsBr doping on the stacking behavior of the lattice planes. Combined
with transient photocurrent, transient photovoltage, and space-charge-limited
current measurements, the transport dynamics and recombination of
the photogenerated charge carriers are characterized. It is demonstrated
that CsBr compositional engineering can significantly affect the perovskite
crystal structure in terms of the orientation distribution of crystal
planes and passivation of trap-state densities, as well as simultaneously
facilitate the photogenerated charge carrier transport across the
absorber and its interfaces. This strategy provides unique insight
into the underlying relationship between the stacking pattern of crystal
planes, photogenerated charge carrier transport, and optoelectronic
properties of solar cells.