From smart phones to wearable sensors, flexible electronics are becoming more common in everyone's lives. It is expected that whether known brittle materials, such as ceramics or semiconductors, can also have metal characteristics, which can not only undergo large bending and deformation, but also be difficult to break under tensile conditions and cause device failure. At present, in collaboration with Professor Shi Xun and Researcher Chen Lidong of the Shanghai Institute of Ceramics, Chinese Academy of Sciences, and Professor Yuri Grin of the Max Planck Institute in Germany, he has discovered the first flexible inorganic semiconductor material, silver sulfide, and successfully developed and prepared film. The new material is expected to be widely used in flexible electronics. The results were published in the journal Nature Materials on the 10th.

Silver sulfide is a typical new semiconductor material with anomalous metal expansion. It has a zigzag fold layered monoclinic structure. It consists of 4 S and 4 Ag atoms to form an 8-atom ring. The ring and the ring are connected by S atoms. Its crystal structure is like a "track" paved by a train. This structure gives the silver sulfide a strange and unique "magic" of mechanical properties. It has the same ductility and deformation ability as metal, and does not cause material damage and fragmentation under external forces and large strains. Its material processing fragments are similar to metal as slender winding filaments, and general ceramics and Semiconductor processing chips are fine particles or powder. The research team also found that the maximum compression deformation of silver sulfide can reach more than 50%, far exceeding the known ceramic and semiconductor materials, and similar to the mechanical properties of some metals.

The research team further investigated the mechanism and mechanism of these anomalous mechanical properties of silver sulfide. For a material with good sliding ability and ductility, two basic conditions must be met: first, there is a sliding surface with a small energy barrier, which can slide under the action of external forces; Decomposition occurs, and the integrity and integrity of the material is still maintained. The research team calculated and simulated a series of materials including silver sulfide, graphite, diamond, and metal Mg. They also used quantum chemical calculations to reveal the source and mode of action between the α-Ag2S slip surfaces. It was found that silver sulfide meets this Two characteristics, during the sliding process, the atoms constitute the sliding track movement, and the energy fluctuation is small during the sliding process; at the same time, a strong force between these sliding surfaces is guaranteed, and cracks are avoided during the sliding process. The production of even the dissociation of materials.

For flexible electronics applications, the team also prepared a silver sulfide film and found that it has greater deformation ability than bulk materials. At the same time, the electrical properties of the silver sulfide after deformation were also characterized. It was found that after repeated bending and deformation for dozens or hundreds of times, its electrical properties remained basically unchanged or changed little.

Silver sulfide semiconductors have mechanical properties similar to metals. Its wide range of adjustable electrical properties, suitable bandwidth, and large mobility make it expected to be widely used in the field of flexible electronics. At the same time, the research team will also start research to find and discover other semiconductor materials with similar metal mechanical properties.