MoS2 structures differ from 3D, 2D, one-dimensional (1D), or dot structures. Its characteristics and applications also change from one dimension to another; they can be semiconducting, metallic, or superconducting. It exists in several layers and shapes. Its bulk (3D) structure can be tri-agonal (T), hexagonal (H), and Rhombohedral (R), where 2H MoS2 means 2-layer hexagonal shape MoS2. The three main structures are 1T, 2H, and 3R, where the 1T phase coordinates in an octahedral structure and 2H and 3R in a trigonal prismatic structure, as shown in Figure 1. The 1T structure is known to be metallic, while the other two are semiconducting. The monolayer of hexagonal MoS2 is also semiconducting. Both 2H and 3R are used as dry lubricants. Due to the nonlinear optical properties of the 3R phase, it is used in nonlinear optical mass sensing in quantum measurements and biomedicine. For example, for gas sensors, the different phase materials of MoS2 can be interesting in obtaining high sensitivity and rapid desorption.
Figure 1. Different coordination and stacking sequences of the three MoS2 structures 1T, 2H, and 3R. Reproduced from. Published by The Royal Society of Chemistry. Table 1. Comparison between different MoS2 structures. 1H MoS2 is the most stable configuration. It is formed of one layer of Sulfur and one layer of Mo where S-Mo-S are attached through a strong covalent bond like a sandwich, with a thickness of approximately 0.65 nm; the sandwiched S-Mo-S layers are attached through weak Wander Val forces. The conductivity of nano MoS2 depends on the temperature and thickness of the flakes, where conductivity increases with the temperature increase and decreases with increasing the thickness till it reaches the bulk structure. The binding energies and photoluminescence properties are summarized in Table 2. If you are looking for high quality, high purity and cost-effective Molybdenum disulfide, or if you require the latest price of Molybdenum disulfide, please feel free to email contact mis-asia.
