Combining two materials to create super-efficient light-emitting crystals

If you like to bake both cakes and sauces, combine the two ingredients together to make a burger, the taste may be even better. This is also true of materials science. Recently, an international joint research group has combined two popular solar cell materials to create an ultra-efficient light-emitting crystal, which has created a new research platform for LED technology. The related papers were published in the "Nature" magazine published on July 15.

In this study, the team embedded a nanoluminescent colloid, a quantum dot, into the perovskite to form a unique mixed crystal. Perovskite materials can be produced by dissolution methods that allow electrons to move quickly with minimal loss, while quantum dots can emit light efficiently. The two are strong and strong, mutually beneficial and complementary, and achieve maximum efficiency.

The first author of the paper, Gong Xiwen, a doctoral student at the University of Toronto in Canada, said: “Combining the two popular electro-optical materials is a very novel idea. We hope that they can be seamlessly combined with a solid matrix to make use of their respective The strengths."

"When you try to mix two kinds of crystals, the beginning doesn't always go well," said Richard Cumming, a postdoctoral fellow at the University of Toronto who participated in the study. "We must find a new strategy and let them 'forget'. Differing and forming a unique mixed crystal structure."

To do this, they must allow two crystal structures to grow in a manner called "hetero-epitaxy." The team designed a way to connect the two crystal structures at the end of the atom to ensure that they can be aligned smoothly and seamlessly without defects. Ning Zhijun, a co-author of the Shanghai University of Science and Technology, said building a nano-scale "scaffolding" shell around a quantum dot and then allowing the perovskite to grow along "scaffolding," the two materials are perfectly integrated together .

Finally, the researchers got a beautiful black crystal, quantum dots are wrapped in the perovskite "hive", these perovskite materials can funnel electrons into the electronic point, so that its luminous efficiency can be doubled. This approach also avoids the phenomenon of self-absorption that may result from spectral overlap of materials.

The researchers said that this ultra-high-efficiency LED technology can be used not only to illuminate, manufacture displays and night-vision devices, but also to create near-field infrared emission devices and low-cost thin-film solar cells that can recognize gestures. Value. (Reporter Wang Xiaolong)