Homomeric chains of intermolecular bonds scaffold octahedral germanium perovskites.

Perovskites with low ionic radii metal centres (for example, Ge perovskites) experience both geometrical constraints and a gain in electronic energy through distortion; for these reasons, synthetic attempts do not lead to octahedral [GeI] perovskites, but rather, these crystallize into polar non-perovskite structures. Here, inspired by the principles of supramolecular synthons, we report the assembly of an organic scaffold within perovskite structures with the goal of influencing the geometric arrangement and electronic configuration of the crystal, resulting in the suppression of the lone pair expression of Ge and templating the symmetric octahedra. We find that, to produce extended homomeric non-covalent bonding, the organic motif needs to possess self-complementary properties implemented using distinct donor and acceptor sites.

Strain data augmentation enables machine learning of inorganic crystal geometry optimization.

Machine-learning (ML) models offer the potential to rapidly evaluate the vast inorganic crystalline materials space to efficiently find materials with properties that meet the challenges of our time. Current ML models require optimized equilibrium structures to attain accurate predictions of formation energies. However, equilibrium structures are generally not known for new materials and must be obtained through computationally expensive optimization, bottlenecking ML-based material screening.

Bipolar-shell resurfacing for blue LEDs based on strongly confined perovskite quantum dots.

Colloidal quantum dot (QD) solids are emerging semiconductors that have been actively explored in fundamental studies of charge transport and for applications in optoelectronics. Forming high-quality QD solids-necessary for device fabrication-requires substitution of the long organic ligands used for synthesis with short ligands that provide increased QD coupling and improved charge transport. However, in perovskite QDs, the polar solvents used to carry out the ligand exchange decompose the highly ionic perovskites.

Stabilizing Surface Passivation Enables Stable Operation of Colloidal Quantum Dot Photovoltaic Devices at Maximum Power Point in an Air Ambient.

Colloidal quantum dots (CQDs) are promising materials for photovoltaic (PV) applications owing to their size-tunable bandgap and solution processing. However, reports on CQD PV stability have been limited so far to storage in the dark; or operation illuminated, but under an inert atmosphere. CQD PV devices that are stable under continuous operation in air have yet to be demonstrated-a limitation that is shown here to arise due to rapid oxidation of both CQDs and surface passivation.