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Atomistic insights into highly active reconstructed edges of monolayer 2H-WSe 2 photocatalyst

Today, October 9, 2022, is National #NanotechnologyDay in the US. The theme for this year’s National Nanotechnology Day is nanotechnology’s role in understanding and responding to climate change and improving the health of the Earth and its people.

Climate change has necessitated the framing of government regulations and the development of green strategies for reducing CO2 emissions. Scientists worldwide are engaged in efforts to find sustainable solutions to the problem of CO2 level in the air.*

Ascertaining the function of in-plane intrinsic defects and edge atoms is necessary for developing efficient low-dimensional photocatalysts.*

In their article “Atomistic insights into highly active reconstructed edges of monolayer 2H-WSe 2 photocatalyst” Mohammad Qorbani , Amr Sabbah, Ying-Ren Lai, Septia Kholimatussadiah, Shaham Quadir , Chih-Yang Huang, Indrajit Shown, Yi-Fan Huang, Michitoshi Hayashi, Kuei-Hsien Chen and Li-Chyong Chen report the wireless photocatalytic CO2 reduction to CH4 over reconstructed edge atoms of monolayer 2H-WSe2 artificial leaves.*

Their first-principles calculations demonstrate that reconstructed and imperfect edge configurations enable CO2 binding to form linear and bent molecules. Experimental results show that the solar-to-fuel quantum efficiency is a reciprocal function of the flake size. It also indicates that the consumed electron rate per edge atom is two orders of magnitude larger than the in-plane intrinsic defects. Further, nanoscale redox mapping at the monolayer WSe2–liquid interface confirms that the edge is the most preferred region for charge transfer.*

The author’s results pave the way for designing a new class of monolayer transition metal dichal-cogenides with reconstructed edges as a non-precious co-catalyst for wired or wireless hydrogen evolution or CO2 reduction reactions.*

The thickness of the WSe 2 flake was measured by using Atomic Force Microscopy with a NanoWorld Pointprobe® NCHR AFM probe and was controlled by a feedback mechanism. The AFM cantilever was driven under a resonant frequency of ~330 kHz and 42 N m−1 spring constant.*

Figure 4 from “Atomistic insights into highly active reconstructed edges of monolayer 2H-WSe2 photocatalyst” by Mohammad Qorbani et al:
Nanoscale redox mapping and PC performance
a FE-SEM image of the ML WSe2 in dark (control experiment) in the solution containing Ag ions. b FE-SEM images of the ML WSe2 under light after Ag photodeposition for 1 h, respectively. Bright regions show the presence of Ag nanoparticles. Inset illustrates the photoreduction mechanism. Scale bar = 2 μm. c–e AFM height profile measured in the liquid environment, background normalized SECM feedbacks maps for main, and lift scans, respectively. Scale bar = 1 μm. f Color map of the blank-corrected total methane yield as a function of flake sizes (in perimeters) and areas. g Blank-corrected IQE as a function of the average flake perimeter. The black line shows the fitted reciprocal curve. h Stability test for six cycles. Irradiation time for each cycle is 4 h.

*Mohammad Qorbani , Amr Sabbah, Ying-Ren Lai, Septia Kholimatussadiah, Shaham Quadir , Chih-Yang Huang, Indrajit Shown, Yi-Fan Huang, Michitoshi Hayashi, Kuei-Hsien Chen and Li-Chyong Chen
Atomistic insights into highly active reconstructed edges of monolayer 2H-WSe 2 photocatalyst
Nature communications (2022) 13:1256
DOI: https://doi.org/10.1038/s41467-022-28926-0

Please follow this external link to read the full article: https://rdcu.be/cXbA6

Open Access
The article “Atomistic insights into highly active reconstructed edges of monolayer 2H-WSe 2 photocatalyst” by Mohammad Qorbani , Amr Sabbah, Ying-Ren Lai, Septia Kholimatussadiah, Shaham Quadir , Chih-Yang Huang, Indrajit Shown, Yi-Fan Huang, Michitoshi Hayashi, Kuei-Hsien Chen and Li-Chyong Chen is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Electrochemically Synthesized Poly(3-hexylthiophene) Nanowires as Photosensitive Neuronal Interfaces

Poly(3-hexylthiophene) (P3HT), a hole-conducting polymer, generates a lot of interest especially because of its excellent optoelectronic properties (such as good electrical conductivity and high extinction coefficient) and good processability, which make this polymer an excellent choice for building organic optoelectronic devices (e.g., organic solar cells). *

P3HT films and nanoparticles have also been used to restore the photosensitivity of retinal neurons. *

For their article “Electrochemically Synthesized Poly(3-hexylthiophene) Nanowires as Photosensitive Neuronal Interfaces” Szilveszter Gáspár, Tiziana Ravasenga, Raluca-Elena Munteanu, Sorin David, Fabio Benfenati, and Elisabetta Colombo investigated the template-assisted electrochemical synthesis of P3HT nanowires doped with tetrabutylammonium hexafluorophosphate (TBAHFP) and their biocompatibility with primary neurons. *

They were able to show that template-assisted electrochemical synthesis can relatively easily turn 3-hexylthiophene (3HT) into longer (e.g., 17 ± 3 µm) or shorter (e.g., 1.5 ± 0.4 µm) P3HT nanowires with an average diameter of 196 ± 55 nm (determined by the used template) and that the nanowires produce measurable photocurrents following illumination. *

The fact that template-assisted electrochemical synthesis combines polymerization, doping, and polymer nanostructuring into one, relatively simple step is the most important advantage of this method. The possibility of easily tuning the length of the produced nanowires represents another important advantage. *

The authors were also able to demonstrate that primary cortical neurons can be grown onto P3HT nanowires drop-casted on a glass substrate without relevant changes in their viability and electrophysiological properties, indicating that P3HT nanowires obtained by template-assisted electrochemical synthesis represent a promising neuronal interface for photostimulation. *

Szilveszter Gáspár et al. proved the biocompability of the obtained P3HT nanowires upon incubation for different periods with primary neuronal cultures. They demonstrated that their presence does not affect the membrane properties of the neurons or the excitability of the neurons as evaluated by patch-clamp experiments. These results show the potential of the described synthesis methodology to fabricate injectable P3HT-based photosensitive nanowires with high biocompatibility, ultimately paving the way for their exploitation for neuronal photostimulation. *

Atomic Force Microscopy (AFM) was used to characterize P3HT nanowires drop-casted onto glass coverslips. *

The Atomic Force Microscopy images were obtained in air and in intermittent contact-mode using line rates as slow as 0.2 Hz and NanoWorld Pointprobe® NCSTR silicon soft-tapping AFM probes (typical values: resonant frequency 160 kHz, force constant 7.2 N m). The ratio between the set-point amplitude and the free amplitude of the AFM cantilever was set to 0.5–0.6. The obtained AFM images were used to determine both the lengths and the diameters of the nanowires. *

Figure 3 from “Electrochemically Synthesized Poly(3-hexylthiophene) Nanowires as Photosensitive Neuronal Interfaces” by Szilveszter Gáspár et al.: AFM images of “long” P3HT nanowires (A) and of “short” P3HT nanowires (B). NanoWorld Pointprobe NCSTR soft-tapping mode probes were used. — Figure 3 from “Electrochemically Synthesized Poly(3-hexylthiophene) Nanowires as Photosensitive Neuronal Interfaces” by Szilveszter Gáspár et al.:
AFM images of “long” P3HT nanowires (A) and of “short” P3HT nanowires (B).

*Szilveszter Gáspár, Tiziana Ravasenga, Raluca-Elena Munteanu, Sorin David, Fabio Benfenati, and Elisabetta Colombo
Electrochemically Synthesized Poly(3-hexylthiophene) Nanowires as Photosensitive Neuronal Interfaces
Materials 2021, 14(16), 4761, Special Issue Advanced Designs of Materials, Devices and Techniques for Biosensing
DOI: https://doi.org/10.3390/ma14164761 (please follow this external link to read the full article.)

Open Access The article “Electrochemically Synthesized Poly(3-hexylthiophene) Nanowires as Photosensitive Neuronal Interfaces” by Szilveszter Gáspár, Tiziana Ravasenga, Raluca-Elena Munteanu, Sorin David, Fabio Benfenati, and Elisabetta Colombo is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Carbon Dating AFM Tip Style

Have you every wondered how carbon dating in the AFM tip world works?

Cartoon of a nanotools HDC AFM tip and a NanoWorld CDT AFM tip meeting for cheese fondue and complaining how carbonized and peaky they are because they have been under a lot of pressure — Our take on carbon dating in the AFM tip world. Enjoy and have a great 1st of April!