Molybdenum diselenide application

Characteristics of molybdenum diselenide

Like most of the transition metal dichalcogenides and graphite, molybdenum diselenide (MoSe2) has a two-dimensional layered structure - with the individual layers stacked together by weak van der Waals interactions. Due to the larger size and better conductivity of selenium over sulphur, MoSe2 is one of the best TMDCs of metallic nature. This also provides a great opportunity for hosting counterions in  electrochemical energy storage systems (such as lithium-ion and sodium-ion batteries).

Like MoS2, MoSe2 undergoes changes from indirect to direct band-gap transitions when bulk material (such as the bulk crystal) is reduced to monolayer film. However, unlike MoS2, few-layer MoSe2 flakes possess a nearly degenerate indirect and direct band-gap. An increase in temperature/pressure can effectively push the system toward the quasi-2D limit by reducing the coupling between the layers. MoS2, on the other hand, has indirect and direct band-gaps that are well-separated in energy - and hence, far from degenerate. Compared to MoS2, MoSe2 exhibits higher electrical conductivity.

Applications of molybdenum diselenide

In contrast to graphene, exfoliated monolayer or few-layer 2D MoSe2 has a direct band-gap. It has applications in transistors, photo-detectors, and photovoltaics. Due to its layered structure and the unique nature of selenium, MoSe2 has been widely used in lubricants and energy storage devices. 

Molybdenum diselenide MoSe2 single crystals are a great source for obtaining monolayer and few-layer MoSe2 via mechanical or liquid exfoliation. Single crystals can also be used directly in optical and scanning-probe microscopy (such as AFM and TEM studies).