Researchers from Los Alamos National Laboratory, Rice University and Northwestern University have been working on modifying perovskites' manufacturing technique and producing a new variety of 2D layered perovskite with exceptional strength and increased power transformation capability.

Three types of large-area solar cells made out of two-dimensional perovskites. At left, a room-temperature cast film; upper middle is a sample with the problematic band gap, and at right is the hot-cast sample with the best energy performance.Three types of large-area solar cells made out of two-dimensional perovskites. At left, a room-temperature cast film; upper middle is a sample with the problematic band gap, and at right is the hot-cast sample with the best energy performance.

Using a spin-casting technique, the team managed to create layered crystals whose electrons flow vertically down the material without being blocked, midlayer, by organic cations. The researchers stated that “the new 2D perovskite is both more efficient and more stable, both under constant lighting and in exposure to the air, than the existing 3D organic-inorganic crystals”.

The challenge was to discover something that works in a much enhanced manner than 3D perovskites, which have extraordinary photophysical properties and power transformation capabilities greater than 20%, but are still plagued by poor quality performance in stress tests of light, heat and humidity.

An earlier study by the Los Alamos team offered awareness on 3D perovskite performance recovery, given a small timeout in a dark space, and by moving to the stronger 2D approach, the team obtained improved results. The 2D crystals that were studied earlier by the Northwestern team lost power when the organic cations hit the sandwiched space between the layers, knocking the cells down to a 4.73% transformation efficiency because of the out-of-plane arrangement of the crystals. However, using the hot casting method to produce the more streamlined, vertically arranged 2D material appears to have removed the gap. At present the 2D material has accomplished 12% productivity.

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