Optical Tuning of Low-Dimensional Materials under High Pressure

As a thermodynamic parameter, independent of temperature and composition, pressure provides a new dimension for material science research and innovation. Pressure has become an important source for developing new concepts, creating new theories and exploring new materials. Here, some advances in optical properties regulation of low-dimensional materials under high pressure are summarized. By changing the exciton binding energy and the distortion behavior of halide octahedra under pressure, the luminescence of low-dimensional halide perovskites experienced a stark change from "0" to "1". Meanwhile, we innovatively put forward the new concept of "pressure-induced emission (PIE)". Through introducing the pressure effect, it is able to regulate the surface ligands of nanomaterials, change the interaction and energy level coupling between the surface ligands and CdSe quantum dots. This will promote the Hirshfeld charge transfer, thus realizing the significant emission enhancement of CdSe quantum dots by nearly one order of magnitude. With the help of high-pressure regulation on energy band structure, we successfully achieved the core/shell configuration transition of CdSe/CdS semiconductor nanocrystals from quasi-type Ⅱ to type Ⅰ core-shell structure. The above work will deepen the understanding of the structure-property relationship of luminescent materials under extreme compression conditions. The research results provide new methods for the design and preparation of low-dimensional materials with specific functionality.