Optical Properties of ITO/Glass Substrates Modified by Silver Nanoparticles for PV Applications

Round 1

Reviewer 1 Report

The starting point of this work is fundamentally interesting, since Ag modification, especially nanoparticle type, is of great importance in achieving high-performance PV devices with boosted efficiency and transmittance.  However, the paper is not well presented, thus major revision is necessary before its publication:

[1] The figures are not in good quality, compared with those in high-level journals, authors should make them better.

[2] The language issue should be well taken care of. A proof-reading seems unavoidable.

[3] ITO enabled high-performance PV works should be cited: Energy Environ. Sci. 2022, 15, 2479.; Angew. Chem. Int. Ed. 2022, 61, e202205168.; Energy Environ. Sci. 2022, 15, 4601.; Matter 2022, 5, 725.

[4] What’s the difference of Ag nanoparticles and evaporated Ag thin film? In my experience, the latter one doesn’t harm the %T of ITO as much as the nanoparticles shown in this paper.

[5] The 4-type ITO %T spectra all suffer a sudden drop and then rising part, this should be the measurement error, possibly the equipment’s malfunction. Therefore, the %T spectra should be re-assured

[6] How about using Au nanoparticles to modify the ITO?

Author Response

Thank you very much for your valuable comments that allow us to significantly improve our work

[1] The figures are not in good quality, compared with those in high-level journals, authors should make them better.

Indeed, the figures were hardly legible. We change of size of the font in the descriptions and axes, we increased the line thickness

[2] The language issue should be well taken care of. A proof-reading seems unavoidable.

Thank for your comment. We did proof-read of manuscript.

[3] ITO enabled high-performance PV works should be cited: Energy Environ. Sci. 2022, 15, 2479-2488., Angew. Chem. Int. Ed. 2022, 61, e202205168.; Energy Environ. Sci. 2022, 15, 4601.; Matter 2022, 5, 725.

Thank for your comment. We cited proposed articles in the introduction.

[4] What’s the difference of Ag nanoparticles and evaporated Ag thin film? In my experience, the latter one doesn’t harm the %T of ITO as much as the nanoparticles shown in this paper.

During the process, which is named 10 nm, the NPs are the biggest. The layer starts to be creating. The transmittance is decreasing, and the reflectance is increasing. The layer is becoming mirror-like. NPs, which are non-homogeneous as evaporated Ag thin film and have lower transmission.

[5] The 4-type ITO %T spectra all suffer a sudden drop and then rising part, this should be the measurement error, possibly the equipment’s malfunction. Therefore, the %T spectra should be remeasured

Thank you for your comment. All samples were measured with a Bentham spectrophotometer for comparison. Additionally, we again remeasured samples by Cary 5000 spectrophotometer and corrected graphs and inserted them into the article.

The only difference we noticed was that there is no ‘jump’ around 900nm for ITO4, as the reviewer suggested. In addition, we noticed that a similar situation occurred for ITO1. Therefore, we corrected a graph for ITO1, too.

[6] How about using Au nanoparticles to modify the ITO?

The use of Au nanoparticles to modify the ITO gives better results in application for thin film cells, as the study in the following work: Parametry konwersji fotowoltaicznej dla fotoogniw plazmonicznych na bazie ZnO z nanocząstkami srebra i złota, doi:10.15199/48.2016.09.09

However, the technological process for the use of Au nanoparticles is much more expensive than that for Ag nanoparticles. Therefore, we focus on cheaper solutions, which in the case of mass production would have a much better possibility of commercialization.

Reviewer 2 Report

Comments and Suggestions for Authors

In this work entitled “Optical properties of ITO/glass substrates modified by silver nanoparticles for PV applications” by G. Wisz et al, the study is based on the optical response of 3, 5, and 10 nm silver particles deposited on different types of ITO/glass followed by the calculation of the optical band width, refractive index, and dielectric function. The reactive DC magnetron sputtering of ITO layer was followed by transmittance and reflectance analysis. Illustrated transmittance and reflectance graphs show a thickness dependent pattern, mainly affected by the initial deposited ITO properties with the highest transparency for the samples prepared on ITO1 coating in various thickness range. The 5nm Ag coating on ITO4 samples showed the lowest reflectance value, whereas the Ag reflectance on ITO1 samples exhibits least thickness dependency. Bandgap and refractive index changes are also displayed, and the reported results are reasonable. Overall, this study didn't provide significant novelty, and the analyses performed are inadequately conclusive to meet the study's aims as reported.

Therefore, I would recommend publication pending major revisions:

1.      In Abstract, include tangible values for transmittance, bandgap findings, and changes in refractive index.

2.      In keywords, please include the “ITO” and “DC sputtering” as well.

3.      In the introduction, include relevant literature on studies with similar research scopes, highlight their key outputs, and address the limitations, which is what this current study is attempting to improve based on existing ideas.

4.      In materials and method section, Include the reasons for why this thickness range of 3 t to 10nm is recommended for the Ag layer.

5.      In results and discussion section, many statements (such as in lines: 89, 94, 113, 126, 139, etc.) lack explanation; please expound on the observed trends mentioned.

6.      Line 159, stated “examples of the absorption” are these actual data from samples or examples for results only?

7.      AFM analysis is required to address the different ITO coating function and to explain the differences in optical findings that drop for 5nm and rise for 10nm Ag.

8.      In conclusion, specify the best-case among the four different ITO coatings and the optimum Ag thickness examined in this study.

Thanks.

Comments for author File: Comments.pdf

Author Response

Thank you very much for your valuable comments that allow us to significantly improve our work

1. In Abstract, include tangible values for transmittance, bandgap findings, and changes in refractive index.

Thank you for this comment. We added following sentences in Abstract.

‘The average transmission value in the visible region depends on the thickness of the silver nanoparticle layer and varies from ~50% to ~90%. The average refractive index takes values from the range ~1.4 to ~1.65 and does not depend on the presence and thickness of the silver layer.”

2. In keywords, please include the “ITO” and “DC sputtering” as well.

Thank you for this comment. We add “ITO” and “DC sputtering” in keywords

3. In the introduction, include relevant literature on studies with similar research scopes, highlight their key outputs, and address the limitations, which is what this current study is attempting to improve based on existing ideas.

Thank you for this comment. We added and described some results from literature in the introduction.

4. In materials and method section, Include the reasons for why this thickness range of 3 t to 10nm is recommended for the Ag layer.

The use of thicknesses of Ag nanoparticles cannot limit the transmission, so it is necessary to use very thin layers. In the case of applying thicker than 10 nm for Ag nanoparticles, we observe a very rapid increase in reflection, which limits the possibility of using nanoparticles in photovoltaic devices.

5. In results and discussion section, many statements (such as in lines: 89, 94, 113, 126, 139, etc.) lack explanation; please expound on the observed trends mentioned.

We modified line 89 as below:

The additional layer of silver nanoparticles causes a decrease in the transmission of the layer depending on the thickness of the layer of Ag nanoparticles, especially in the infrared region, that can be explain by absorption of the light by silver nanoparticles.

Line 94 and 113

Thank you for this comment. Unfortunately, based on the current study, we are unable to determine what is the reason for such a behavior of the transmission coefficient.

It is clear that this dependence is determined by differences in the structure of the ITO substrate and individual Ag layers. These differences can be seen in the additional AFM images of the Ag layers and the ITO substrate. Unfortunately, we have not been able to find a correlation between the results of the studies conducted so far.

Line 126 should be considered together with lines 137-139. The explanation is in the following lines. Unfortunately, we used a paragraph, which makes the text difficult to understand, so we remove the paragraph after line 139 so that the explanation refers directly to that line. We also added a sentence commenting on line 126 "Thus, the previously described minimum reflection for a layer of 5 mm thickness can be explained"

6. Line 159, stated “examples of the absorption” are these actual data from samples or examples for results only?

We remove the word "example” because it can be confusing. It referred to the fact that, we provide figures for the ITO1 series and not for the other series (ITO2, ITO3, ITO4). These are actual results for ITO1

7. AFM analysis is required to address the different ITO coating function and to explain the differences in optical findings that drop for 5nm and rise for 10nm Ag.

Thank you for this comment. We studied the AFM graph, see section 3.2.

8. In conclusion, specify the best-case among the four different ITO coatings and the optimum Ag thickness examined in this study

Thank you for this comment. We added the following sentences in conclusion.

“When we only take into account the optical properties of the ITO coatings for their application in photovoltaic devices, ITO1 shows the highest transmittance, which is optimal (see Figure 2). However, at the presence, we cannot determine which type of ITO and which Ag thickness will allow to obtain maximum efficiency for photovoltaic solar cells based on titanium dioxide and copper oxide. This will be verified by the next experiment.”

Round 2

Reviewer 1 Report

The decent revision deserves publication.

Author Response

Thank you for your attention to the language. We made a few more necessary language corrections.

Reviewer 2 Report

Comments and Suggestions for Authors

In the revised draft, presented analyses are adequately conclusive to meet the study's aims.

Therefore, I would recommend publication pending minor revision.  

-        In section 3.2, AFM analysis, include the table of AFM parameters including (Average roughness, RMS, Sq, Height-valley difference Sy, Peak height Sp, Valley depth Sv, Height distribution Sq/Sa. 

Thanks.

Author Response

Thank you for your attention to the language. We made a few more necessary language corrections.

In section 3.2, we added a table containing the AFM roughness analysis for selected surfaces.