New semiconductor material emits bright, circularly polarized light

A team of researchers, led by Prof. Dr. Felix Deschler at Heidelberg University’s Institute for Physical Chemistry, has achieved a significant breakthrough in semiconductor technology. They’ve developed a semiconductor material known as chiral perovskite, which not only efficiently generates light but also imparts a specific spin to that light. This advancement holds enormous promise for applications in optoelectronics, telecommunications, and information processing.

For a long time, the goal has been to produce bright, circularly polarized light, but it has proven challenging to achieve both distinct chirality (the rotation of light in a specific direction) and high photoluminescence quantum efficiency (PLQE), which measures a material’s ability to emit light. Inorganic semiconductors excel in brightness but typically lack light polarization. Conversely, organic molecular semiconductors exhibit high polarization but often suffer from brightness limitations due to dark conditions.

Prof. Felix Deschler and his team have bridged this gap by creating a hybrid metal-halide perovskite semiconductor with a layered structure. They’ve integrated a specially designed chiral organic molecule into the perovskite structure. This innovation, using a small aromatic molecule with a strategically placed halogen atom, has given rise to unique chiral perovskites designated as R/S-3BrMBA2PbI4.

Crystals of chiral hybrid perovskites. Credit: Heidelberg University

These chiral perovskites, with their significantly distorted crystal structures, outperform other materials in generating circularly polarized luminescence, even at room temperature. Through advanced laser spectroscopy, the researchers have unveiled the processes behind this special light generation, with polarization and brightness values surpassing those seen in previous chiral semiconductors.

Furthermore, the researchers have demonstrated the promising applications of these novel materials. They’ve incorporated them into light detectors capable of recording and distinguishing the chirality of incident light. Additionally, the team has developed light-emitting diodes that can convert electricity into light using these materials.

This groundbreaking research was conducted as part of the ERC Starting Grant “Twisted Perovskites—Control of Spin and Chirality in Highly-luminescent Metal-halide Perovskites,” led by Prof. Deschler, and the results have been published in Science Advances.

Source: Heidelberg University

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