Cultivating triple-decker hybrid crystals for lasers

Researchers at Duke University and Purdue University have shown that they can control the energy levels of electrons and holes (positive charge carriers) in perovskites by controlling the arrangement of multiple inorganic and organic layers within crystals using a novel technique. This tuning influences the materials’ optoelectronic properties and their ability to emit light of specific energies, demonstrated by their ability to function as a source of lasers.

Appearing in the journal Nature Chemistry, the research is the result of a collaboration between several experimental and theoretical teams. The experimental teams synthesise the materials and characterise their properties, while the theoretical team performs computational simulations to predict the electronic structure and properties of the materials.

An important foundation of the computational work is an investment into the creation of computational simulation codes for materials properties. “This study involved simulating structures including up to around 900 atoms with an advanced methodology, which requires powerful supercomputers that can handle some of the largest calculations on the planet,” Volker Blum, associate professor of mechanical engineering at Duke University, said.

Perovskite materials are a class of compounds that have gained attention in materials science due to their unique properties, particularly in the area of semiconductors. These materials, which are defined by their specific crystalline structure, can be used in applications like light-emitting diodes (LEDs), solar cells and lasers. The researchers focused on refining the structural control of layered perovskite materials with organic semiconductor incorporation. While these types of perovskites have been made before with single layers of organic and inorganic components, the ability to precisely control the thickness of the inorganic component and, thus, adjust the properties of the material has remained elusive for more complex “organic semiconductor incorporated perovskites”.

The research findings showed that the organic components added to the inorganic layers affect the semiconductor properties, such as energy levels and light emission. By controlling the arrangement of atoms and the number of layers in these structures, the researchers can tune the optical and electronic properties of the resulting material.

Image credit: Duke University