Thin and soft new semiconductor materials can be used to make micro and nano optoelectronic devices

roperties, thickness of only a few nanometers, good optical properties... The reporter learned from Nanjing University of Technology that the research group of the professor of the physics Department of the school has prepared an ultra-thin high-quality two-dimensional lead iodide crystal, and through it to achieve the regulation of the optical properties of two-dimensional transition metal sulfide materials, which provides a new idea for the manufacture of solar cells and photodetectors. The results were published in the latest issue of the international journal Advanced Materials.

"The ultra-thin lead iodide nanosheets we have prepared for the first time, the technical term is' atomically thick wide band gap two-dimensional PbI2 crystals', which is an ultra-thin semiconductor material with a thickness of only a few nanometers." Sun Yan, the first author of the paper and a doctoral candidate at Nanjing University of Technology, said that they used the solution method to synthesize, which has very low equipment requirements and has the advantages of simple, fast and efficient, and can meet the needs of large-area and high-yield material preparation. The synthesized lead iodide nanosheets have regular triangular or hexagonal shape, average size of 6 microns, smooth surface and good optical properties.

The researchers combined this ultra-thin nanosheet of lead iodide with two-dimensional transition metal sulfides, artificially designed, stacked them together, and obtained different types of heterojunctions, because the energy levels are arranged in different ways, so lead iodide can have different effects on the optical performance of different two-dimensional transition metal sulfides. This band structure can effectively improve the luminous efficiency, which is conducive to the production of devices such as light-emitting diodes and lasers, which are applied in display and lighting, and can be used in the field of photodetectors and photovoltaic devices.

This achievement realizes the regulation of optical properties of two-dimensional transition metal sulfide materials by ultra-thin lead iodide. Compared with traditional optoelectronic devices based on silicon-based materials, this achievement has the characteristics of flexibility, micro and nano. Therefore, it can be applied to the preparation of flexible and integrated optoelectronic devices. It has a broad application prospect in the field of integrated micro and nano optoelectronic devices, and provides a new idea for manufacturing solar cells, photodetectors and so on.