Criticality of Symmetry in Rational Design of Chalcogenide Perovskites

Chalcogenide perovskites
constitute an emerging class of promising
photovoltaic materials that are stable and less toxic than popular
lead-halide perovskites. Transition-metal and chalcogenide doping
are the possible strategies for improving the photovoltaic properties
of these materials via the band gap engineering. At the same time,
doping can facilitate nonradiative charge-carrier recombination in
these materials, adversely affecting their photovoltaic properties.
We report a systematic study of electronic structure and nonadiabatic
dynamics in transition-metal- and chalcogenide-doped barium-zirconium-sulfide-based
perovskites. The potential of these doping strategies to modulate
the performance of photovoltaic materials is explored. Through the
detailed analysis of the factors affecting the dynamics, we illustrate
how symmetry (both structural and orbital) and decoherence can be
critical to furnishing the most favorable properties. The noted factors
of symmetry and decoherence may provide new rational design principles
for efficient photovoltaics.