Solvent-dripping modulated 3D/2D heterostructures for high-performance perovskite solar cells.

The controlled growth of two-dimensional (2D) perovskite atop three-dimensional (3D) perovskite films reduces interfacial recombination and impedes ion migration, thus improving the performance and stability of perovskite solar cells (PSCs). Unfortunately, the random orientation of the spontaneously formed 2D phase atop the pre-deposited 3D perovskite film can deteriorate charge extraction owing to energetic disorder, limiting the maximum attainable efficiency and long-term stability of the PSCs. Here, we introduce a meta-amidinopyridine ligand and the solvent post-dripping step to generate a highly ordered 2D perovskite phase on the surface of a 3D perovskite film.

Balancing Surface Chemistry and Flake Size of MXene-Based Electrodes for Bioelectrochemical Reactors.

MXenes have excellent properties as electrode materials in energy storage devices or fuel cells. In bioelectrochemical systems (for wastewater treatment and energy harvesting), MXenes can have antimicrobial characteristics in some conditions. Here, different intercalation and delamination approaches to obtain TiCT MXene flakes with different terminal groups and lateral dimensions are comprehensively investigated.

Enhanced cation interaction in perovskites for efficient tandem solar cells with silicon.

To achieve the full potential of monolithic perovskite/silicon tandem solar cells, crystal defects and film inhomogeneities in the perovskite top cell must be minimized. We discuss the use of methylenediammonium dichloride as an additive to the perovskite precursor solution, resulting in the incorporation of in situ-formed tetrahydrotriazinium (THTZ-H) into the perovskite lattice upon film crystallization. The cyclic nature of the THTZ-H cation enables a strong interaction with the lead octahedra of the perovskite lattice through the formation of hydrogen bonds with iodide in multiple directions.

Double-side 2D/3D heterojunctions for inverted perovskite solar cells.

Defects at the top and bottom interfaces of three-dimensional (3D) perovskite photoabsorbers diminish the performance and operational stability of perovskite solar cells owing to charge recombination, ion migration and electric-field inhomogeneities. Here we demonstrate that long alkyl amine ligands can generate near-phase-pure 2D perovskites at the top and bottom 3D perovskite interfaces and effectively resolve these issues. At the rear-contact side, we find that the alkyl amine ligand strengthens the interactions with the substrate through acid-base reactions with the phosphonic acid group from the organic hole-transporting self-assembled monolayer molecule, thus regulating the 2D perovskite formation.