Small-angle scattering to reveal the colloidal nature of halide perovskite precursor solutions

Abstract

Halide perovskites are crystalline semiconductors gaining incremental attention as low-cost, high-performance materials for optoelectronics. Their processing from solution at low temperature is compatible with fast manufacturing of thin-film devices, including...

Exploring Nanoscale Structure in Perovskite Precursor Solutions Using Neutron and Light Scattering

“…The domain sizes compare favorably with our own DLS data and agree well with other SANS measurements from the literature. 27 However, the simplicity of this model allows the SLD of this “solute domain” to be optimized and the composition determined, and this has provided us with an intriguing insight into the structure of these precursor solutions. Apart from the fresh MAPbI 3 sample, the SLD values for the perovskite components are found to be higher than the calculated values for the pure phases or their mixtures likely to be present (see Table S1 ).…”

“…Small-angle neutron scattering (SANS) and small-angle X-ray scattering (SAXS) are powerful and proven techniques used for characterizing the size and shape of colloids in dispersion and macromolecules in solution − and can readily cope with optically opaque samples, as the scattering results from periodic variations in nuclear scattering length and electron density, respectively. In 2021, Flatken et al published a study examining perovskite precursor solutions using both SAXS and SANS, which enabled them to confirm the presence of particles at the nm length scale in MAPbI 3 solutions. They modeled their small angle data using a cylindrical form factor of dimensions 0.5 nm × 0.7 nm (diameter × length), coupled with a hard sphere structure factor, that is, a lead-halide octahedra presenting as a cylinder.…”

Modulating preferred crystal orientation for efficient and stable perovskite solar cells—From progress to perspectives

“…The characteristics of the colloids are closely related to the choice of raw materials and solvents. Different precursor systems such as MAPbX 3 , FAPbX 3 , CsPbX 3 , CsMAFAPbX 3 , Sn, and Pb‐Sn mixed perovskites would definitely present various colloidal chemical properties, such as solute coordination interaction, species of colloidal complexes, colloidal particle sizes, and so on 170–173 . Furthermore, these colloidal properties can also be significantly affected by additives with various functional groups.…”

“…Different precursor systems such as MAPbX 3 , FAPbX 3 , CsPbX 3 , CsMAFAPbX 3 , Sn, and Pb-Sn mixed perovskites would definitely present various colloidal chemical properties, such as solute coordination interaction, species of colloidal complexes, colloidal particle sizes, and so on. [170][171][172][173] Furthermore, these colloidal properties can also be significantly affected by additives with various functional groups. Hence, exploring the fundamental properties of the perovskite precursors of different systems is a key step in investigating the crystal growth to achieve preferred orientation.…”

What Happens at Surfaces and Grain Boundaries of Halide Perovskites: Insights from Reactive Molecular Dynamics Simulations of CsPbI$_{3}$

“…Halide salts are mixed in solution with metal halide precursors, where solvent evaporation causes the formation of colloidal particles in solution, with further evaporation resulting in the growth of these particles in a polycrystalline perovskite film. [5][6][7][8] This simple fabrication procedure offers wide tunability in compositions and dimensions. However, it generally introduces a wide variety of defects in the material, ranging from point defects to crystal surfaces and grain boundaries.…”