Molybdenum disulfide (MoS₂) is one of the compounds discussed nowadays due to its outstanding properties that allowed its usage in different applications. Its band gap and its distinctive structure make it a promising material to substitute graphene and other semiconductor devices. It has different applications in electronics especially sensors like optical sensors, biosensors, electrochemical biosensors that play an important role in the detection of various diseases’ like cancer and Alzheimer. It has a wide range of energy applications in batteries, solar cells, microwave, and Terahertz applications. It is a promising material on a nanoscale level, with favorable characteristics in spintronics and magnetoresistance. In this review, we will discuss MoS₂ properties, structure and synthesis techniques with a focus on its applications and future challenges.

Molybdenum disulfide (MoS₂) is a promising transition metal dichalcogenide (TMD) that has exceptional electronic, magnetic, optical, and mechanical properties. It can be semiconducting, superconducting, or an insulator according to its polymorph. Its bandgap structure changes from indirect to direct when moving towards its nanostructures, which opens a door to bandgap engineering for MoS₂. Its supercapacitive and catalytic activity was recently noticed and studied, in order to include this material in a wide range of energy applications. In this work, we present MoS₂ as a future material for energy storage and generation applications, especially solar cells, which are a cornerstone for a clean and abundant source of energy. Its role in water splitting reactions can be utilized for energy generation (hydrogen evolution) and water treatment at the same time. Although MoS₂ seems to be a breakthrough in the energy field, it still faces some challenges regarding its structure stability, production scalability, and manufacturing costs.

Plasmonic nanostructures have played a key role in extending the activity of photocatalysts to the visible light spectrum, preventing the electron–hole combination and providing with hot electrons to the photocatalysts, a crucial step towards efficient broadband photocatalysis. One plasmonic photocatalyst, Au/TiO₂, is of a particular interest because it combines chemical stability, suitable electronic structure, and photoactivity for a wide range of catalytic reactions such as water splitting. In this review, we describe key mechanisms involving plasmonics to enhance photocatalytic properties leading to efficient water splitting such as production and transport of hot electrons through advanced analytical techniques used to probe the photoactivity of plasmonics in engineered Au/TiO₂ devices. This work also discusses the emerging strategies to better design plasmonic photocatalysts and understand the underlying mechanisms behind the enhanced photoactivity of plasmon-assisted catalysts.

Hybrid organic–inorganic perovskite (HOIP) photovoltaics have emerged as a promising new technology for the next generation of photovoltaics since their first development 10 years ago, and show a high-power conversion efficiency (PCE) of about 29.3%. The power-conversion efficiency of these perovskite photovoltaics depends on the base materials used in their development, and methylammonium lead iodide is generally used as the main component. Perovskite materials have been further explored to increase their efficiency, as they are cheaper and easier to fabricate than silicon photovoltaics, which will lead to better commercialization. Even with these advantages, perovskite photovoltaics have a few drawbacks, such as their stability when in contact with heat and humidity, which pales in comparison to the 25-year stability of silicon, even with improvements are made when exploring new materials. To expand the benefits and address the drawbacks of perovskite photovoltaics, perovskite–silicon tandem photovoltaics have been suggested as a solution in the commercialization of perovskite photovoltaics. This tandem photovoltaic results in an increased PCE value by presenting a better total absorption wavelength for both perovskite and silicon photovoltaics. In this work, we summarized the advances in HOIP photovoltaics in the contact of new material developments, enhanced device fabrication, and innovative approaches to the commercialization of large-scale devices.

We report on reflective electro-optic sampling measurements of terahertz emission from nanometer-gate-length InGaAs-based high electron mobility transistors. The room temperature coherent gate-voltage tunable emission is demonstrated. We establish that the physical mechanism of the coherent terahertz emission is related to the plasma waves driven by simultaneous current and optical excitation. A significant shift of the plasma frequency and the narrowing of the emission with increasing channel’s current are observed and explained as due to the increase in the carriers’ density and drift velocity.

Phosphorene is a new two-dimensional material that has recently attracted much attention owing to its fascinating electrical, optical, thermal and chemical properties. Here, we report on high-quality exfoliation of black phosphorus nanosheets, with controllable size produced in large quantities by liquid-phase exfoliation using N -methyl-2-pyrrolidone (NMP) as a solvent under ambient conditions. The as-synthesized few layers show a great potential for solar energy conversion based on the optical results shown in this work.