Quantum dot-induced phase stabilization of α-CsPbI3 perovskite for high-efficiency photovoltaics.

We show nanoscale phase stabilization of CsPbI quantum dots (QDs) to low temperatures that can be used as the active component of efficient optoelectronic devices. CsPbI is an all-inorganic analog to the hybrid organic cation halide perovskites, but the cubic phase of bulk CsPbI (α-CsPbI)-the variant with desirable band gap-is only stable at high temperatures. We describe the formation of α-CsPbI QD films that are phase-stable for months in ambient air.

Thermal stability of spherical nanoporous aggregates and formation of hollow structures by sintering--a phase-field study.

Nanoporous structures are widely used for many applications and hence it is important to investigate their thermal stability. We study the stability of spherical nanoporous aggregates using phase-field simulations that explore systematically the effect of grain boundary diffusion, surface diffusion, and grain boundary mobility on the pathways for microstructural evolution. Our simulations for different combinations of surface and GB diffusivity and GB mobility show four distinct microstructural pathways en route to 100% density: multiple closed pores, hollow shells, hollow shells with a core, and multiple interconnected pores.