Graphene + quantum dots new hybrid materials will help next-generation display research

Researchers from the Indian Institute of Science (IISc) have created a new mixture of graphene and quantum dots. This breakthrough may inspire the next generation of efficient and controllable displays and LED displays. Quantum dots are nano-semiconductor crystals, which have the potential to revolutionize various technologies, including photovoltaic power generation, medical imaging, and quantum computing. Quantum dots can absorb ultraviolet light and produce clear and bright colors, which are particularly suitable for the production of next-generation TVs, smart phones and LED displays. However, they are not good electrical conductors, so they are inefficient when used alone on equipment. In order to improve efficiency, researchers tried to combine them with graphene (a good conductor). The added graphene will make up for the conductivity of the product, and graphene will also work even after the manufacturing is completed or the device is opened or closed at will. Although this combination will work well for photodetectors and sensors, it is actually useless for displays and LED displays, because quantum dots lose their light-emitting ability when fused with graphene. By modifying some experimental conditions, IISc scientists have found a way to eliminate this effect and developed a highly efficient and adjustable hybrid material. The results announced by ACS Photonics provide the possibility for a new generation of the most advanced displays and LEDs. Quantum dots are very small particles whose performance is far superior to traditional semiconductors. When activated by ultraviolet light, they can produce different colors of visible light according to their size. For example, small dots produce blue light, while larger ones emit red light. They can absorb light well, but they are not good electrical conductors. Therefore, devices based on quantum dots that convert light into electricity are not efficient. On the contrary, graphene is almost transparent to light, but it is an excellent electrical conductor. When the two are combined, graphene can theoretically quickly absorb the energy absorbed by the quantum dots, thereby reducing energy loss and converting it into electrical signals. This makes it possible to create extremely efficient devices such as photodetectors. Jaydeep Kumar Basu, a professor in the Department of Physics of IISc and the first author of the paper, said: “Both are the best.” In the above case, the transfer of energy to graphene makes the quantum dots hardly leave any energy to emit light, making it Cannot be used in displays or LEDs. Basu said: 'Because of these effects, the application of these hybrid materials has not yet begun. As far as quantum dots are concerned, graphene acts like a sponge and does not allow any energy to be emitted.' Basu's research team tried to use what is called The superradiation phenomenon reacts to overcome this 'quenching' effect. When individual atoms or emitters (such as quantum dots) in a layer are excited, each emits light independently. Under certain conditions, all atoms or emitters can emit light in concert. This produces a very bright light whose intensity is significantly greater than the sum of the emissions of a single one. In previous studies, Basu's research team combined with metal nanoparticles to generate super-radiation on a thin layer of quantum dots under certain experimental conditions. They reproduced these conditions in a new quantum dot-graphene hybrid material to generate super-strong radiation that can offset quenching. When using the data model, they found that this happens when a single quantum dot is 5nm or less apart, and the quantum dot layer and graphene are separated by a distance of 3nm or less. Basu said: 'We are the first to be able to eliminate this 'sponge' effect and keep the signal source active. When super-radiation is the mainstay, the intensity of the light emitted in the presence of graphene is the result of using quantum dots alone. Three times the strength that can be achieved. Basu said: 'The advantage of graphene is that people can also adjust it electronically. The intensity can be changed by simply changing the voltage or current. 'The author said that this research also opens up new ways for the study of how light and matter interact at the nanoscale. The article comes from the phys website, and the original title is Novel hybrid material may inspire highly efficient next-gen displays. Online collection of science and technology.