Semiconductors play a crucial role in modern technology, particularly in fields such as optoelectronics, telecommunications, and information processing. However, until recently, achieving bright, circularly polarized light, which offers immense potential in these applications, has proven to be extremely challenging. In a groundbreaking development, a research team led by Prof. Dr. Felix Deschler at Heidelberg University’s Institute for Physical Chemistry has successfully developed a semiconductor that not only efficiently generates light but also imparts a specific spin to it. This development, centered around a chiral perovskite material, holds significant promise for the future of materials science.
One of the key features that makes this achievement so remarkable is the ability to combine a distinct chirality, representing the rotation of light in a specific direction, with high photoluminescence quantum efficiency (PLQE). Inorganic semiconductors have high brightness but low light polarization, whereas organic molecular semiconductors possess high polarization but suffer from limitations in brightness due to dark conditions. The challenge was to find a material that could merge the advantageous qualities of both groups.
To address these challenges, the research group at Heidelberg University created a hybrid metal-halide perovskite semiconductor with a layered structure. By incorporating a customized chiral organic molecule into the perovskite structure, they were able to achieve the desired brightness and high polarization. This involved integrating a small aromatic molecule with a precisely placed halogen atom into the perovskite structure, resulting in the development of novel chiral perovskites denoted as R/S-3BrMBA2PbI4.
The chiral 3BrMBA2PbI4 perovskites boast remarkably distorted crystal structures, which greatly enhance their degree of circularly polarized luminescence, even at room temperature. It is worth noting that the ability of perovskite materials to tolerate distortion in the crystal structure while maintaining good material performance is a testament to their versatility and potential for further breakthroughs.
Through the utilization of sophisticated ultra-fast laser spectroscopy measurements, the research team successfully unraveled the underlying processes behind the generation of this unique light. They discovered that the polarization and brightness values of the chiral perovskite semiconductors surpassed those of previously used chiral semiconductors, marking a significant advancement in the field.
The potential applications of these novel materials are vast. The researchers demonstrated their applicability in light detectors, which can accurately record and differentiate the chirality of incident light. This holds great promise, particularly in fields such as optical communications and quantum computing, where the ability to distinguish between different polarizations of light is essential. Additionally, the research team developed light-emitting diodes (LEDs) that can generate light from electricity, opening up new avenues for energy-efficient lighting solutions with enhanced polarization properties.
The development of chiral perovskite semiconductors marks an exciting milestone in the world of materials science. The convergence of high luminescence quantum efficiency, strong chirality, and advanced crystal structures has the potential to revolutionize various industries. As this field continues to evolve, further advancements and applications in optoelectronics, telecommunications, and information processing can be expected. This groundbreaking research, conducted as part of the ERC Starting Grant “Twisted Perovskites—Control of Spin and Chirality in Highly-luminescent Metal-halide Perovskites” led by Prof. Felix Deschler, paves the way for a new generation of advanced semiconductor materials.
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