The multifunctional applications of holey graphene.

Earth-abundant and nontoxic kesterite compounds, such as Cu₂ZnSnS₄ (CZTS), Cu₂ZnSnSe₄ (CZTSe), and Cu₂ZnSn(S,Se)₄ (CZTSSe), have made tremendous progress, becoming a hot topic in optoelectronic materials research on power generation through solar energy capture. These compounds can be considered possible alternatives to conventional, toxic, and expensive absorber layers, such as crystalline silicon (c-Si), Cu(In,Ga)Se₂ (CIGS), and CdTe. The p-type semiconductor kesterites (CZTS, CZTSe CZTSSe) are the most promising light absorbers for solar cell applications, reaching record efficiencies of up to 12.7% owing to their unique optical properties. These properties include a variable band gap energy ranging from 1.0 eV (Cu₂ZnSnSe₄) to 1.5 eV (Cu₂ZnSnS₄) and a large optical absorption coefficient of 10⁴ cm⁻¹, which make kesterite a feasible option for photovoltaic technologies scalable to terawatt levels. Furthermore, as kesterite absorbers do not contain any rare metals or toxic materials, one can expect their application to low-cost solar cells in the near future. This review aims to present an overview of the most recent research activity on state-of-the-art kesterite-based absorbers, including a brief introduction to kesterite compounds, deposition methods, and improved device performance through doping with alkali, germanium, and other metal elements either during kesterite synthesis or after growth as a post-deposition treatment. As the key component for improving the power conversion efficiency of the kesterite absorber, doping with alkali, germanium, and other metal elements has attracted much interest and is vital for delivering promising efficiencies. Furthermore, current knowledge on doping, its impact on structural, optical, and electrical properties, and the solar cell performance of kesterite compounds are summarized. Finally, important achievements in this field to date and further directions for improving the solar cell efficiency of kesterite-based absorbers have been summarized.

In this report, highly active hydrous cobalt phosphate thin film electro-catalysts were synthesized by a low cost and one-pot hydrothermal method at 393 K and were evaluated for the oxygen evolution reaction (OER). The impact of varying the hydrolyzing agent, urea, on the structural and morphological properties of hydrous cobalt phosphate thin films and the consequent electro-catalytic performances was studied. The morphology of hydrous cobalt phosphate thin films resembles a microflower-like structure consisting of microplates. Upon urea variation, the microplates undergo changes in thickness and width and eventually transform into microflakes. The remarkable electrocatalytic performance of hydrous cobalt phosphate thin films was observed towards the OER and they exhibit a low overpotential of 292 mV (vs. RHE) at 10 mA cm⁻² current density with a Tafel slope of 98 mV dec⁻¹ in 1.0 M KOH electrolyte. Also, the stability of the electrocatalyst is demonstrated by continued electrolysis, showing that the hydrous cobalt phosphate thin film electro-catalyst sustains superior long-term electrochemical stability for 10 h at 10 mA cm⁻² constant current density. The enhanced electrocatalytic performance of hydrous cobalt phosphate thin film electro-catalysts was attributed to a high ECSA (1210 cm⁻²) and low electrochemical impedance imparted by the microflower structure with microflake-like morphology.

The multifunctional applications of copper tin sulfide (CTS) compound.

In the present work, Cu₂SnS₃ (CTS) nanoparticles were synthesized using the hot injection method.

We present a simplistic, ultrafast, and facile hydrothermal deposition of ternary Cu₂SnS₃ nanoparticles (CTS NPs). The fabricated CTS NPs show superior antimicrobial and photocatalytic activities. In the presence of UV-Visible illumination, methylene blue (MB) dye was studied for photocatalytic dye degradation activity of CTS NPs. Excellent efficiency is shown by incorporating CTS NPs to degrade MB dye. There is a ~95% decrease in the absorbance peak of the dye solution within 120 min. Similarly, CTS NPs tested against three bacterial strains, i.e., B. subtilis, S. aureus, P. vulgaris, and one fungal strain C. albicans, defining the lowest inhibitory concentration and zone of inhibition, revealed greater antimicrobial activity. Hence, it is concluded that the CTS NPs are photocatalytically and antimicrobially active and have potential in biomedicine.