Researchers have developed a new technique that allows them to precisely control the structure of a material called layered hybrid perovskites (LHPs) at the atomic level.
This breakthrough opens up exciting possibilities for creating next-generation lasers and LEDs, as well as improving solar cells.
The team from North Carolina State University, led by Professor Aram Amassian, published their findings in the journal Matter.
Perovskites are a class of materials known for their unique crystalline structure, which gives them special optical, electronic, and quantum properties. Layered hybrid perovskites are made of very thin layers of a perovskite semiconductor material separated by organic layers.
These materials are especially good at converting electrical charge into light, making them useful for advanced applications like LEDs, lasers, and even integrated circuits in electronic devices.
However, until now, scientists didn’t fully understand how to engineer LHPs to control their performance. This new technique sheds light on how to fine-tune these materials to make them more efficient.
At the heart of the discovery are quantum wells—sheets of semiconductor material that are sandwiched between organic layers.
The size and distribution of these wells are crucial for how energy flows through the material.
For example, a quantum well that is two atoms thick has more energy than one that is five atoms thick. Ideally, the quantum wells should have a smooth size distribution, creating a gradual energy slope that allows energy to flow efficiently from high-energy areas to low-energy areas.
Previously, researchers noticed a puzzling difference between what X-ray diffraction and optical spectroscopy revealed about the size of quantum wells in LHPs.
X-ray diffraction would indicate quantum wells of only one thickness, while optical spectroscopy showed multiple sizes. The researchers needed to understand this mismatch to improve the performance of LHPs.
Through a series of experiments, they discovered that nanoplatelets—very thin sheets of perovskite material—were the missing piece of the puzzle.
These nanoplatelets form on the surface of the solution used to create LHPs and act as templates for the material layers beneath them. As the nanoplatelets grow thicker, so do the quantum wells they create, eventually forming a three-dimensional crystal. This explains why different techniques were showing different results.
The exciting part of the discovery is that the researchers found a way to control the growth of these nanoplatelets. By stopping their growth at specific sizes, they could tune the quantum wells to create highly efficient materials for LEDs and lasers. This control allows the materials to funnel energy quickly and efficiently, making them ideal for use in next-generation technology.
The team also found that nanoplatelets play a similar role in other types of perovskite materials, such as those used in solar cells. By using nanoplatelets, they could improve the structure of these materials, making them better at converting light into electricity and more stable over time.
This breakthrough could have a major impact on the future of lasers, LEDs, and solar energy, as it allows scientists to engineer materials with precision, unlocking their full potential.
