Stabilization of the Metastable Lead Iodide Perovskite Phase via Surface Functionalization.

Metastable structural polymorphs can have superior properties and applications to their thermodynamically stable phases, but the rational synthesis of metastable phases is a challenge. Here, a new strategy for stabilizing metastable phases using surface functionalization is demonstrated using the example of formamidinium lead iodide (FAPbI) perovskite, which is metastable at room temperature (RT) but holds great promises in solar and light-emitting applications. We show that, through surface ligand functionalization during direct solution growth at RT, pure FAPbI in the cubic perovskite phase can be stabilized in nanostructures and thin films at RT without cation or anion alloying.

Basal-Plane Ligand Functionalization on Semiconducting 2H-MoS Monolayers.

Molybdenum disulfide (MoS) is a two-dimensional material promising for electronic, optical, and catalytic applications. To fully harness its potential, functionalization is essential to controlling its properties. However, MoS functionalization has been mostly limited to either 1T-phase MoS or the edges of 2H-phase MoS, and the chemistry of covalent functionalization on the basal plane of 2H-MoS is poorly understood.

Color-Pure Violet-Light-Emitting Diodes Based on Layered Lead Halide Perovskite Nanoplates.

Violet electroluminescence is rare in both inorganic and organic light-emitting diodes (LEDs). Low-cost and room-temperature solution-processed lead halide perovskites with high-efficiency and color-tunable photoluminescence are promising for LEDs. Here, we report room-temperature color-pure violet LEDs based on a two-dimensional lead halide perovskite material, namely, 2-phenylethylammonium (C6H5CH2CH2NH3(+), PEA) lead bromide [(PEA)2PbBr4].

Designing Efficient Solar-Driven Hydrogen Evolution Photocathodes Using Semitransparent MoQxCly (Q = S, Se) Catalysts on Si Micropyramids.

Silicon micropyramids with n(+) pp(+) junctions are demonstrated to be efficient absorbers for integrated solar-driven hydrogen production systems enabling significant improvements in both photocurrent and onset potential. When conformally coated with MoSx Cly , a catalyst that has excellent catalytic activity and high optical transparency, the highest photocurrent density for Si-based photocathodes with earth-abundant catalysts is achieved.