Chemical Approaches to Addressing the Instability and Toxicity of Lead–Halide Perovskite Absorbers

The
impressive rise in efficiencies of solar cells employing the three-dimensional
(3D) lead–iodide perovskite absorbers APbI3 (A =
monovalent cation) has generated intense excitement. Although these
perovskites have remarkable properties as solar-cell absorbers, their
potential commercialization now requires a greater focus on the materials’
inherent shortcomings and environmental impact. This creates a challenge
and an opportunity for synthetic chemists to address these issues
through the design of new materials. Synthetic chemistry offers powerful
tools for manipulating the magnificent flexibility of the perovskite
lattice to expand the number of functional analogues to APbI3. To highlight improvements that should be targeted in new materials,
here we discuss the intrinsic instability and toxicity of 3D lead–halide
perovskites. We consider possible sources of these instabilities and
propose methods to overcome them through synthetic design. We also
discuss new materials developed for realizing the exceptional photophysical
properties of lead–halide perovskites in more environmentally
benign materials. In this Forum Article, we provide a brief overview
of the field with a focus on our group’s contributions to identifying
and addressing problems inherent to 3D lead–halide perovskites.