Quantification of electron accumulation at grain boundaries in perovskite polycrystalline films by correlative infrared-spectroscopic nanoimaging and Kelvin probe force microscopy

Organic-inorganic halide perovskites are materials of high interest for the development of solar cells.

Learning more about the relationship between the electrical properties and the chemical compositions of perovskite at the nanoscale can help to understand how the interrelations of both can affect device performance and contribute to an understanding on how to best design perovskite active layer structures.*

For the article “Quantification of electron accumulation at grain boundaries in perovskite polycrystalline films by correlative infrared-spectroscopic nanoimaging and Kelvin probe force microscopy” Ting-Xiao Qin, En-Ming You, Mao-Xin Zhang, Peng Zheng, Xiao-Feng Huang, Song-Yuan Ding, Bing-Wei Mao and Zhong-Qun Tian used correlative infrared-spectroscopic nanoimaging ( IR-spectroscopy ) by scattering-type scanning near-field optical microscopy ( s-SNOM ) and Kelvin probe force microscopy ( KPFM ) to contribute to the discussion whether nanometer-sized grain boundaries (GBs) in polycrystalline perovskite films play a positive or negative role in solar cell performance.*

The integrated KPFM and s-SNOM measurements were performed by the authors to acquire the surface potential and infrared near-field image simultaneously through a single-pass scan and thereby learn more about the relationships between the electrical properties and spectral information at the grain boundaries of the investigated material ( polycrystalline CH3NH3Pbl3 perovskite films ).*

The results of the correlated s-SNOM and KPFM imaging presented in the article show that the electron accumulations are enhanced at the grain boundaries (GBs) of the investigated polycrystalline perovskite film, particularly under light illumination which would assist in electron-hole separation and therefore would be a positive influence on the performance of the solar cell.*

NanoWorld conductive platinum-iridium coated Arrow AFM probes ( Arrow-NCPt ) were used to perform the s-SNOM IR imaging.

Figure 4 from “Quantification of electron accumulation at grain boundaries in perovskite polycrystalline films by correlative infrared-spectroscopic nanoimaging and Kelvin probe force microscopy” by Ting-Xiao Qin  et al.
Correlative KPFM and s-SNOM nanoimaging on perovskite.
a AFM topography (1 μm × 1 μm); b Contact potential difference (CPD); and c simultaneously acquired infrared near-field image; d one-dimensional line profiles of the topography, CPD and infrared near-field amplitude along the white dashed lines marked in a–c. The scale bars are 200 nm.
NanoWorld Arrow-NCPt AFM probes were used to perform the s-SNOM IR imaging
Figure 4 from “Quantification of electron accumulation at grain boundaries in perovskite polycrystalline films by correlative infrared-spectroscopic nanoimaging and Kelvin probe force microscopy” by Ting-Xiao Qin  et al.
Correlative KPFM and s-SNOM nanoimaging on perovskite.
a AFM topography (1 μm × 1 μm); b Contact potential difference (CPD); and c simultaneously acquired infrared near-field image; d one-dimensional line profiles of the topography, CPD and infrared near-field amplitude along the white dashed lines marked in a–c. The scale bars are 200 nm.

*Ting-Xiao Qin, En-Ming You, Mao-Xin Zhang, Peng Zheng, Xiao-Feng Huang, Song-Yuan Ding, Bing-Wei Mao and Zhong-Qun Tian
Quantification of electron accumulation at grain boundaries in perovskite polycrystalline films by correlative infrared-spectroscopic nanoimaging and Kelvin probe force microscopy
Light: Science & Applications volume 10, Article number: 84 (2021)
DOI: https://doi.org/10.1038/s41377-021-00524-7

Please follow the external link to read the whole article: https://rdcu.be/clg7f

Open Access : The article “Quantification of electron accumulation at grain boundaries in perovskite polycrystalline films by correlative infrared-spectroscopic nanoimaging and Kelvin probe force microscopy” by Ting-Xiao Qin, En-Ming You, Mao-Xin Zhang, Peng Zheng, Xiao-Feng Huang, Song-Yuan Ding, Bing-Wei Mao and Zhong-Qun Tian 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 https://creativecommons.org/licenses/by/4.0/.

AFM probes for Magnetic Force Microscopy – screencast on NanoWorld MFM tips passes 2000 views mark

The screencast about NanoWorld AFM probes for Magnetic Force Microscopy held by Dr. Marco Becker has just passed the 2000 views mark. Congratulations Marco!

Magnetic Force Microscopy is a type of Atomic Force Microscopy in which a magnetised AFM tip is used to measure magnetic interactions between the tip and the surface of a magnetic sample. These detected interactions are then used to reconstruct the magnetic structure of the sample surface

NanoWorld currently offers two types of MFM tips:

MFMR – This type of magnetic AFM tip is coated with a hard magnetic coating on the tip side and yields a very high force sensitivity, while simultaneously enabling tapping and lift mode operation.

S-MFMR – These magnetic AFM tips are coated with a soft magnetic layer on the tip side and are designed for the measurement of magnetic domains in soft magnetic samples.

Pb2+ Uptake by Magnesite: The Competition between Thermodynamic Driving Force and Reaction Kinetics

When they are in put in contact with carbonate minerals dangerous environmental pollutants such as Pb2+ and Cd2+ are taken up by the solid phase assemblage and can be removed from aqueous solutions.*

As carbonates can be found almost everywhere and are easily exploitable this makes them interesting materials for environmental remediation.*

However, magnesite ( MGS ) is well-known for the slow dissolution and growth kinetics at room temperature conditions in the so-called dolomite problem.*

In their article “Pb2+ Uptake by Magnesite: The Competition between Thermodynamic Driving Force and Reaction Kinetics” Fulvio Di Lorenzo, Tobias Arnold and Sergey V. Churakov use in situ atomic force microscopy (AFM) to investigate the growth of {10.4} magnesite surfaces in the absence and in the presence of Pb2+ as well as the effect of solution ageing.*

In their study the authors attempt to answer the question if and under which circumstances magnesium carbonate could be used in removing Pb from wastewater.*

The experimental results presented in above mentioned article have the object to discuss and evaluate the theoretical possibilities and the practical limitations that must be taken into account for the development of environmental remediation technologies based on magnesite.*

The experiments conducted in this study by  Fulvio Di Lorenzo et al. demonstrate that, although the thermodynamic conditions are encouraging, the transformation reaction between magnesite and cerrusite makes it improbably that it will play a crucial role in the development of remediation processes for PbII pollution.*

The authors of the study conclude that, although the thermodynamic conditions are encouraging, an environmental remediation process based on MGS as the substrate for a solvent-mediated transformation reaction is unlikely to play a crucial part in industrial applications due to the slow kinetics of MGS dissolution. However, the sluggish kinetics of MGS precipitation is favourable for Pb entrapment by the precipitation of carbonate from Mg2+ and Pb2+-bearing solutions, leading to a strong PbII enrichment in the solid phase even in far-from-equilibirum conditions.*

The in situ flow-through Atomic Force Microscopy was performed using Arrow-UHFAuD AFM probes in tapping mode.

Figure 8 from “Pb2+ Uptake by Magnesite: The Competition between Thermodynamic Driving Force and Reaction Kinetics” by Fulvio Di Lorenzo et al:
 In situ observation of {10.4} surfaces of MGS in contact with acidic solution, pH 4 (HNO3). The images were acquired in tapping mode. The first row corresponds to height channels, while the second row reports the respective amplitude channels. (A) The dissolution at 25 °C is sluggish and it is not possible to detect any dissolution feature. (B) In the same conditions but at higher temperature (60 °C), dissolution features are observed on the {10.4} surfaces of MGS, despite the retrograde solubility. Yellow and blue lines of constant size are used to highlight the evolution of etch pits and step edges, respectively. This evidence demonstrates that the existence of kinetic barriers controls the dissolution of MGS at room temperature conditions. NanoWorld Arrow-UHFAuD AFM probes were used.
Figure 8 from “Pb2+ Uptake by Magnesite: The Competition between Thermodynamic Driving Force and Reaction Kinetics” by Fulvio Di Lorenzo et al:
 In situ observation of {10.4} surfaces of MGS in contact with acidic solution, pH 4 (HNO3). The images were acquired in tapping mode. The first row corresponds to height channels, while the second row reports the respective amplitude channels. (A) The dissolution at 25 °C is sluggish and it is not possible to detect any dissolution feature. (B) In the same conditions but at higher temperature (60 °C), dissolution features are observed on the {10.4} surfaces of MGS, despite the retrograde solubility. Yellow and blue lines of constant size are used to highlight the evolution of etch pits and step edges, respectively. This evidence demonstrates that the existence of kinetic barriers controls the dissolution of MGS at room temperature conditions.

*Fulvio Di Lorenzo, Tobias Arnold, and Sergey V. Churakov
Pb2+ Uptake by Magnesite: The Competition between Thermodynamic Driving Force and Reaction Kinetics
Minerals 2021, 11(4), 415
DOI: https://doi.org/10.3390/min11040415

Please follow this external link to read the full article: https://www.mdpi.com/2075-163X/11/4/415

Open Access : The article “Pb2+ Uptake by Magnesite: The Competition between Thermodynamic Driving Force and Reaction Kinetics” by Fulvio Di Lorenzo, Tobias Arnold, and Sergey V. Churakov 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 https://creativecommons.org/licenses/by/4.0/.