Transition metal dichalcogenides

Transition-metal-chalcogenides-400x226

In the TMDCs family, especially MoS2 and WS2 are the emerging 2D materials for various applications in electrical, catalytic and optical, due to their direct bandgap semiconducting nature. Monolayer MoS2/WS2 have shown are the promising candidate due to easy band gap tuning with layer number. We successfully synthesized the in-plane and edge oriented MoS2 structure. Currently, we are working on the effect of orientation of TMDCs structures on the various mentioned applications.

Solar cell photovoltaics

Solar cell photovoltaics

Earth receives more energy from the sun on a given day than the energy consumed by the total world population in a year. For the future energy requirement of the mass population, energy harvesting through solar photovoltaics is on the leading edge among other renewable energy resources. The main challenges in marketing solar cell technology are the high manufacturing costs and the non-availability of novel techniques to enhance cell efficiency. The main expenditure is the cost of the materials used for solar cell fabrication. It is well documented that 40% of the cost of solar cell fabrication is on the materials side, and hence any reduction in the quantity of material can lead to a drop in the cost of solar cells. A thin-film solar cell is a leap forward in this area to cut down the costs effectively. CZTS is the most seeking absorber material for thin-film solar cells. In addition to being economically and ecologically viable, CZTS possesses desirable properties like p-type conductivity, large absorption coefficient α >104 cm-1and bandgaps of around 1.5 eV which is very close to the theoretical optimum value.

The potential of CZTS was recognized by Ken taro Ito in 1988 and CZTS thin film was fabricated by atom beam sputtering and demonstrated a photovoltaic effect. In the past few years, there has been tremendous growth in the number of publications relating to CZTS with a large number of techniques for its synthesis and characterization. Solar cells employing Cu2ZnSnS4(Se)4 absorber layer showed efficiency up to 12.7% which is much lower than its SQ limit. The major challenges in CZTS based solar cells are narrow its phase stability which makes secondary phases easy to form during the growth process, inefficient carrier management, and photon management.

Solar Blind Photodetectors

Solar Blind Photodetectors

Next-generation photodetector would be using a wide-bandgap semiconductor which can work in an intense environment without any interference from background surroundings.UV photodetectors fabricated from wide band-gap semiconductors such as β-Ga2O3is the most promising material among wide-bandgap semiconductors like AlGaN, ZnMgO, BN, and diamond. They have attained increasing attention in recent years because of their high thermal and chemical stability as well as high tolerance of electric field determining its possibility to work in hostile environments.

Development of high-performance TCO’s

Transparent conducting oxides are a special class of material which exhibit a remarkable good electrical conductivity (~103S/cm) like metals and remarkable good optical transmittance (>80%) in visible and IR region. Generally, oxides are assumed to be an insulator due to their large bandgap but TCO is exceptional oxides. Due to this idiosyncratic property, they are devastatingly used in Research and industry.

So far they are generally found in crystalline nature but recently a new group of conventional TCOs is proposed which are amorphous in nature having comparable optoelectronic properties as crystalline TCOs giving the advantage of being flexible as well. The easy and cheap fabrication technique is an essential step to make them usable widely. Physical vapor deposition (PVD) techniques are used at a large scale in the fabrication of TCO thin films which used as an electrode in the passive devices like a photovoltaic, organic light-emitting diode (OLED) and active layer inactive devices like thin-film transistor (TFT).

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