Tag Archives: nanoparticles

Nontoxic pyrite iron sulfide nanocrystals as second electron acceptor in PTB7:PC71BM-based organic photovoltaic cells

Iron disulfide ( FeS2 ) is a natural earth-abundant and nontoxic material with possible applications in lithium batteries, transistors or photovoltaic (PV) devices. According to the analysis carried out by Wadia et al., among 23 semiconducting materials, FeS2 is the best candidate for the development of large-scale solar cells at low cost (<2 × 10−6 ¢/W). Furthermore, FeS2 exhibits excellent optoelectronic properties such as a band gap of 0.8 to 1.38 eV, a high optical absorption coefficient (2 × 105 cm−1), high carrier mobility (2 to 80 cm2/Vs) and a large charge carrier lifetime (200 ps). Therefore, FeS2 nanoparticles (NPs) can be a good alternative for PV applications.*

In “Nontoxic pyrite iron sulfide nanocrystals as second electron acceptor in PTB7:PC71BM-based organic photovoltaic cells “ Olivia Amargós-Reyes, José-Luis Maldonado, Omar Martínez-Alvarez, María-Elena Nicho, José Santos-Cruz, Juan Nicasio-Collazo, Irving Caballero-Quintana and Concepción Arenas-Arrocena report the synthesis of nontoxic pyrite iron sulfide ( FeS2 ) nanocrystals (NCs) using a two-pot method. Moreover, they study the influence of these NCs incorporated into the PTB7:PC71BM active layer of bulk-heterojunction ternary organic photovoltaic ( OPV ) cells.*

The AFM roughness images presented in this article were acquired in dynamic force mode using NANOSENSORS™ PointProbe® Plus PPP-NCLAu AFM probes.

Figure 7 from “Nontoxic pyrite iron sulfide nanocrystals as second electron acceptor in PTB7:PC71BM-based organic photovoltaic cells” shows the 2D (left) and 3D (right) AFM images of the OPVs with different concentrations of FeS2 recorded in the noncontact mode. The roughness of the OPV surface is increased gradually as the FeS2 concentration increases (Table 1 and Figure 7), such that traps for the charge carriers could occur and the leakage current could increase. Because of the FeS2 agglomerates, the OPV parameters tend to decrease, free charges cannot be efficiently extracted. This effect is most prominent for the OPV cells with 1% of FeS2 (Figure 7 and Supporting Information File 1, Figure S2d).
Figure 7 from “Nontoxic pyrite iron sulfide nanocrystals as second electron acceptor in PTB7:PC71BM-based organic photovoltaic cells” by Olivia Amargós-Reyes et al.:
2D (left) and 3D (right) AFM images of the OPVs with different concentrations of FeS2
(a) 0.0 wt %, b) 0.25 wt %, c) 0.5 wt % and d) 1.0 wt %) recorded in noncontact mode.

*Olivia Amargós-Reyes, José-Luis Maldonado, Omar Martínez-Alvarez, María-Elena Nicho, José Santos-Cruz, Juan Nicasio-Collazo, Irving Caballero-Quintana and Concepción Arenas-Arrocena
Nontoxic pyrite iron sulfide nanocrystals as second electron acceptor in PTB7:PC71BM-based organic photovoltaic cells
Beilstein Journal of . Nanotechnology 2019, 10, 2238–2250.
DOI: doi:10.3762/bjnano.10.216

Please follow this external link to read the full article: https://www.beilstein-journals.org/bjnano/articles/10/216#R65

Open Access: The article “Nontoxic pyrite iron sulfide nanocrystals as second electron acceptor in PTB7:PC71BM-based organic photovoltaic cells” by Olivia Amargós-Reyes, José-Luis Maldonado, Omar Martínez-Alvarez, María-Elena Nicho, José Santos-Cruz, Juan Nicasio-Collazo, Irving Caballero-Quintana and Concepción Arenas-Arrocena 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/.

From Polymer to Magnetic Porous Carbon Spheres: Combined Microscopy, Spectroscopy, and Porosity Studies

In their research paper “From Polymer to Magnetic Porous Carbon Spheres: Combined Microscopy, Spectroscopy, and Porosity Studies” Federico Cesano, Sara Cravanzola, Valentina Brunella, Alessandro Damin and Domenica Scarano, after having first reported the preparation of polymer waste-derived microporous carbon microspheres (SBET ~800 m2/g) 100–300 μm in size, investigate the morphology, porous texture and the surface properties of carbon and of magnetic carbon microspheres by multiple techniques.*

The multi-technique methodology they used aims at an extensive description of the different characteristics of activated carbons with magnetic properties.

For the Atomic Force Microscopy described in this paper NANOSENSORS™ SSS-MFMR AFM probes for high resolution magnetic force imaging were used for the topography images as well as the MFM imaging.

Figure 7 from “From Polymer to Magnetic Porous Carbon Spheres: Combined Microscopy, Spectroscopy, and Porosity Studies” by F. Cesano et al:
Three images described from left to right of Fe3O4-based carbon microspheres: first image on the left (a) AFM topography, middle image (b) the related phase signal, and the image on the right (c) MFM phase shift images at H = 60 nm lift height obtained in a second scan. The phase shift range in (c) is ~ 0.6 m°.
Figure 7 from “From Polymer to Magnetic Porous Carbon Spheres: Combined Microscopy, Spectroscopy, and Porosity Studies” by F. Cesano et al:
Fe3O4-based carbon microspheres: (a) AFM topography, (b) the related phase signal, and (c) MFM phase shift images at H = 60 nm lift height obtained in a second scan. The phase shift range in (c) is ~ 0.6 m°. e description

*Federico Cesano, Sara Cravanzola, Valentina Brunella, Alessandro Damin and Domenica Scarano
From Polymer to Magnetic Porous Carbon Spheres: Combined Microscopy, Spectroscopy, and Porosity Studies
Frontiers in Materials 6:84 (2019)
DOI: https://doi.org/10.3389/fmats.2019.00084

Please follow this external link to read the full research article: https://www.frontiersin.org/articles/10.3389/fmats.2019.00084/full

Open Access: The article « From Polymer to Magnetic Porous Carbon Spheres: Combined Microscopy, Spectroscopy, and Porosity Studies” by Federico Cesano, Sara Cravanzola, Valentina Brunella, Alessandro Damin and Domenica Scarano which is cited above 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/.

Observing single magnetite nanoparticles with a diameter of 10nm by using NANOSENSORS SSS-MFMR AFM probes

In their publication “Understanding electrostatic and magnetic forces in magnetic force microscopy: towards single supermagnetic nanoparticle resolution” Alexander Krivcov, Tanja Junkers and Hildegard Möbius describe methods to suppress capacitive coupling effects in MFM hiding the magnetic signal of magnetic nanoparticles.

During MFM measurements performed in an interleave mode moving the tip at a certain distance to the sample surface the tip is exposed not only to magnetic forces but to electrostatic forces between tip and substrates. In case of analyzing nanoparticles laying on a flat substrate, the electrostatic forces changes noticeably with increasing tip to substrate distance whenever the tip is retracted over a nanoparticle. This capacitive signal may overwhelm the magnetic signal that should be detected instead.

The authors propose several approaches to reduce these capacitive signals. The change in electrostatic forces could be minimized by avoiding retraction of tip over the nanoparticle. Therefore, it is proposed to use interleave linear mode following a linear approximation of the sample surface instead of the interleave lift mode following the sample surface as measured. By that, changes in distance between sample substrate and tip at the nanoparticles are avoided. Moreover, they propose using a substrate with a work function comparable to that of the tip in order to reduce electrostatic forces, in general. By applying an appropriate tip bias remaining electrostatic forces could compensated and further suppressed. Finally, the authors suggest using a tip that is as sharp as possible for decreasing the area of the capacitor and NANOSENSORS SSS-MFMR probes are the best choice for this.

The impact of the above mentioned optimizations have been validated experimentally by the authors. Finally, it turned out that if using super sharp magnetic tips further methods suppressing capacitive effects were not necessary. The authors were able to detect superparamagnetic nanoparticles at the single particle level on copper substrate with a NANOSENSORS SSS-MFMR probe without using additional parameters as e. g. tip bias or external magnetic field.Figure 12 from: A. Krivcov et. al, Understanding electrostatic and magnetic forces in magnetic force microscopy: towards single supermagnetic nanoparticle resolution: Figure 12. (a) topography of copper substrate with single magnetite nanoparticle; (b) phase image in 11 nm lift height with an attraction at the place of the nanoparticle; (c) Cross section of a single magnetite nanoparticle (dotted line in (a)) with 10 nm diameter taken on copper substrate with NANOSENSORS SSS-MFMR AFM probe

Figure 12  from: A. Krivcov et. al, Understanding electrostatic and magnetic forces in magnetic force microscopy: towards single supermagnetic nanoparticle resolution: Figure 12. (a) topography of copper substrate with single magnetite nanoparticle; (b) phase image in 11 nm lift height with an attraction at the place of the nanoparticle; (c) Cross section of a single magnetite nanoparticle (dotted line in (a)) with 10 nm diameter taken on copper substrate with SSS-MFMR tip

A. Krivcov, T. Junkers, and H. Möbius
Understanding electrostatic and magnetic forces in magnetic force microscopy: towards single superparamagnetic nanoparticle resolution
J. Phys. Commun., vol. 2, no. 7, p. 075019, 2018
DOI: https://doi.org/10.1088/2399-6528/aad3a4

The article “Understanding electrostatic and magnetic forces in magnetic force microscopy: towards single superparamagnetic nanoparticle resolution” by A. Krivcov, T. Junkers, and H. Möbius is licensed under the Creative Commons Attribution 3.0 License. To view a copy of this license, visit http://creativecommons.org/licenses/by/3.0.