No abstract

The structural diversity and tunable optoelectronic properties of halide perovskites originate from the rich chemistry of metal halide ionic octahedron [MX6] n-(M = Pb 2+ , Sb 3+ , Te 4+ , Sn 4+ , Pt 4+ , etc.; X = Cl -, Br -, I -). The properties of the extended perovskite solids are dictated by the assembly, connectivity, and interaction of these octahedra within the lattice environment. Hence, the ability to manipulate and control the assembly of the octahedral building blocks is paramount for constructing new perovskite materials. Here, we propose a systematic supramolecular strategy for the assembly of [MX6] noctahedra into a solid extended network. Interaction of alkali metal-bound crown ethers with [M(IV)X6] 2octahedron resulted in a structurally and optoelectronically tunable "dumbbell" structural unit in solution. Single crystals with diverse packing geometries and symmetries will form as the solid assembly of this new supramolecular building block. This supramolecular assembly route introduces a new general strategy for designing halide perovskite structures with potentially new optoelectronic properties.

The applications of triplet–triplet annihilation-based photon upconversion (TTA-UC) in solar devices have been limited by the challenges in designing a TTA-UC system that is efficient under aerobic conditions. Efficient TTA-UC under aerobic conditions is typically accomplished by using soft matter or solid-state media, which succeed at protecting the triplet excited states of upconverters (sensitizer and annihilator) from quenching by molecular oxygen but fail at preserving their mobility, thus limiting the TTA-UC efficiency (ΦUC). We showcase a protein/lipid hydrogel that succeeded in doing both of the above due to its unique multiphasic design, with a high ΦUC of 19.0 ± 0.7% using a palladium octaethylporphyrin sensitizer. This hydrogel was made via an industrially compatible method using low-cost and eco-friendly materials: bovine serum albumin (BSA), sodium dodecyl sulfate (SDS), and water. A dense BSA network provided oxygen protection while the encapsulation of upconverters within a micellar SDS environment preserved upconverter mobility, ensuring near-unity triplet energy transfer efficiency. In addition to heavy atom-containing sensitizers, several completely organic, spin–orbit charge-transfer intersystem crossing (SOCT-ISC) Bodipy-based sensitizers were also studied; one of which achieved a ΦUC of 3.5 ± 0.2%, the only reported SOCT-ISC-sensitized ΦUC in soft matter to date. These high efficiencies showed that our multiphasic design was an excellent platform for air-tolerant TTA-UC and that it can be easily adapted to a variety of upconverters.