WO₃ Films Grown by Spray Pyrolysis for Smart Windows Applications

Round 1

Reviewer 1 Report

The article contains interesting information and can be accepted for publication after minor revisions. See details here below.

1. (Line 73) Tungstic acid should be more properly written as “H₂WO₄”.
2. (Line 75) “LiCLO₄” should be replace with “LiClO₄”
3. (Figure 1) The quality of the figure is very low. Please address this problem.
4. (Line 271) Please revise the format of section 3.4.
5. (Lines 141-144) A provisional explanation for the opposite behavior observed by changing the concentration of the precursor would be desirable. Rather than commenting on the individual effects (concentration or volume) a discussion should be made on the interaction between these parameters (multivariate combined effect).
6. In the Introduction section recent and relevant references about other synthetic strategies for the growth of W oxide nanostructured layers are missing, namely, direct thermal oxidation of W metal films (DOI: 10.1002/pssr.202000235), physical vapor deposition (DOI: 10.1016/j.mssp.2022.106534) and hydrothermal methods (DOI: 10.1016/j.spmi.2014.05.039). Please cite these articles possibly with other ones to provide a more complete state of the art on the fabrication of W oxide films.

Author Response

We thank the reviewer for his constructive comments. All the suggestions were considered and the manuscript was corrected/modified accordingly. The revised version of the paper was also modified in order to overcome some similarity issues according to the editorial request. Detailed replay to each comment is inserted in bold font bellow in between the lines. Any remaining format errors due to the template incompatibility with our software will be resolved together with the mdpi team further on, together with any possible typing errors, if the manuscript would be accepted.

1. (Line 73) Tungstic acid should be more properly written as “H₂WO₄”.

Corrected. Thank you.

1. (Line 75) “LiCLO₄” should be replace with “LiClO₄”

Corrected. Thank you.

1. (Figure 1) The quality of the figure is very low. Please address this problem.

Corrected. Thank you.

1. (Line 271) Please revise the format of section 3.4.

Corrected. Thank you.

1. (Lines 141-144) A provisional explanation for the opposite behavior observed by changing the concentration of the precursor would be desirable. Rather than commenting on the individual effects (concentration or volume) a discussion should be made on the interaction between these parameters (multivariate combined effect).

Thank you for your observation. The revised version of the manuscript includes a possible explanation for the different charge transfer behavior.

1. In the Introduction section recent and relevant references about other synthetic strategies for the growth of W oxide nanostructured layers are missing, namely, direct thermal oxidation of W metal films (DOI: 10.1002/pssr.202000235), physical vapor deposition (DOI: 10.1016/j.mssp.2022.106534) and hydrothermal methods (DOI: 10.1016/j.spmi.2014.05.039). Please cite these articles possibly with other ones to provide a more complete state of the art on the fabrication of W oxide films.

Thank you for your suggestion. The respective growth methods and references were inserted in the Introduction.

We hope that the revised version of the manuscript is improved and acceptable for publication.

Reviewer 2 Report

This is a review of the paper entitled “WO3 films grown by spray pyrolysis for smart windows applications” written by E. Koudoumas and others. The paper investigates the effect of precursor concentration and deposition time on the electrochemical, electrochromic and optical properties of the prepared WO3 films. The research work seems to be interesting and could be published in Coatings but not with minor revision.

• I did not notice the reason of behavior change in figure 3(e, f) compared to the other diagrams in this figure. It needs further explanation.
• The results section is well written but mostly has a reporting mode. There should be more discussion on the results.
• There should be a distance between the number and its unit, for example, 250◦C in line 69 on page 2, 0.1M in line 112 on pane 3, 1V in line 109 on page 3 and etc. The whole text should be corrected.
• The same format should be used throughout the paper, for example, Figure 1(page 5), Fig. 2(page 5), fig. 6c(page 8), figure 7(page 9).

Comments for author File: Comments.pdf

Author Response

We thank the reviewer for his constructive comments. All the suggestions were considered and the manuscript was corrected/modified accordingly. The revised version of the paper was also modified in order to overcome some similarity issues according to the editorial request. Detailed replay to each comment is inserted in bold font bellow in between the lines. Any remaining format errors due to the template incompatibility with our software will be resolved together with the mdpi team further on, together with any possible typing errors, if the manuscript would be accepted.

Comments and Suggestions for Authors

This is a review of the paper entitled “WO3 films grown by spray pyrolysis for smart windows applications” written by E. Koudoumas and others. The paper investigates the effect of precursor concentration and deposition time on the electrochemical, electrochromic and optical properties of the prepared WO3 films. The research work seems to be interesting and could be published in Coatings but not with minor revision.

• I did not notice the reason of behavior change in figure 3(e, f) compared to the other diagrams in this figure. It needs further explanation.

Thank you for your observation. The revised version of the manuscript includes a possible explanation for the observed behavior.

• The results section is well written but mostly has a reporting mode. There should be more discussion on the results.

Thank you for your observation. The revised version of the manuscript includes some more discussion of the results but, at this stage of preliminary studies, more discussion would only be speculative. Our research is ongoing and more explanations would become available in our further scientific reports. We hope that the reviewer understands us.  

• There should be a distance between the number and its unit, for example, 250◦C in line 69 on page 2, 0.1M in line 112 on pane 3, 1V in line 109 on page 3 and etc. The whole text should be corrected.

Corrected. Thank you.

• The same format should be used throughout the paper, for example, Figure 1(page 5), Fig. 2(page 5), fig. 6c(page 8), figure 7(page 9).

Corrected. Thank you.

We hope that the revised version of the manuscript is improved and acceptable for publication.

Reviewer 3 Report

Authors studied the electrochromic phenomena based on WO₃ film. Although the topic itself is interesting, I recommend a major revision before any publication.

Comments:

Abstract part: English should be improved.

Line 69:  degree symbol => (correction needed)

Line 75: LiCLO₄ => LiClO₄     (Note: L should be a small letter, l)

Line 84: Tungstic => tungstic

Line 95: field emission scanning electron microscope

          => field emission scanning electron microscope (FE-SEM)

              (Note: you need to introduce FE-SEM initials, here)

Line 110: LiClO4  => LiClO₄  (Note: 4 should be a subscript)

Line 115 :   5 ml => 5 mL (Note: for reader-friendly, I recommend use "mL" symbol in this manuscript. Please check all the other places, also)

Figure 1. (a) and (b): Please include scale for both y-axis and x-axis.

              (Note: a detailed scale is missing )

Figure 1. a, b, c, e, d, and f  => a, b, c, d, e, and f

                (Note: Rearrange your figures)

Line 153: don’t => do not   (Note: a formal writing)

Table 1: Physical quantities should be italic.

              (ml => mL)

Figure 2: Please input a "scale bar" so that people can understand your sample’s size

             (Note, at least, in one place, you should input a scale bar.)

Line 176 : attributed to => is attributed to

Line 190: Physical parameter should be italic.

Table: Dimension for CE is cm²C^-1 but you wrote cm^-2C^-1 (it is wrong)

           (Check all the other parts in your manuscript)

Line 205, 207, and 208: CE’s dimension wrong

Figure 4: y-axis: CE’s dimension wrong

Line 236: cm²/C => cm²C^-1 (Note: for consistency)

Line 240: physical parameter should be italic

Figure 6: Authors showed only 3 SEM figures.  "It is critical." You should include more SEM data according to Table 2’s condition.

Figure 6: Figure’s caption should be revised.

                (a), (b), and (c) is not clear. (You wrote a, b and c in the middle)

               WO3=> WO₃  (Note: 3 should be a subscript)

field emission scanning electron microscope (FE-SEM) => FE-SEM

    (Note: if you introduce it in the experimental part, only initial is enough)

Figure 6’s caption: the nanostructured film ??? 

(Note: your scale is just 40 um. In this condition, you cannot say anything about "nanostructure". I think it may be a "microstructure")

Figure 7: y-axis’s tile should be in the middle.

             (Note: now it is at the right corner)

Figure 7’s caption: WO3 => WO₃ (Note: 3 should be a subscript)

Line 287: WO3 => WO₃ (Note: 3 should be a subscript)

Line 299: WO3 => WO₃ (Note: 3 should be a subscript)

Line 307: Conclusion Part

(You did not show any nanostructure. Hence, you cannot say WO₃ nanostructured thin films)

Otherwise, you should show some nanoscale data, which is missing in this manuscript. 

Line 317: tetragonal crystal ????

                (Note: in Line 282, you said it is monoclinic. How it is “tetragonal” suddenly in the conclusion????)

Overall, this manuscript is not much polished.

A major revision is required.

Author Response

We thank the reviewer for the constructive comments. All the suggestions were considered and the manuscript was corrected/modified accordingly. The revised version of the paper was also modified in order to overcome some similarity issues according to the editorial request. Detailed replay to each comment is inserted in bold font bellow in between the lines. Any remaining format errors are due to the template incompatibility with our software and will be resolved together with the mdpi team further on, together with any possible typing errors, if the manuscript would be accepted.

Comments:

Abstract part: English should be improved. Corrected. Thank you.

Line 69:  degree symbol => (correction needed) Corrected. Thank you.

Line 75: LiCLO₄ => LiClO₄     (Note: L should be a small letter, l) Corrected. Thank you.

Line 84: Tungstic => tungstic Corrected. Thank you.

Line 95: field emission scanning electron microscope Corrected. Thank you.

          => field emission scanning electron microscope (FE-SEM) Corrected. Thank you.

              (Note: you need to introduce FE-SEM initials, here)

Line 110: LiClO4  => LiClO₄  (Note: 4 should be a subscript) Corrected. Thank you.

Line 115 :   5 ml => 5 mL (Note: for reader-friendly, I recommend use "mL" symbol in this manuscript. Please check all the other places, also) Corrected. Thank you.

Figure 1. (a) and (b): Please include scale for both y-axis and x-axis. The figures were improved> We hope that now it is OK.

              (Note: a detailed scale is missing )

Figure 1. a, b, c, e, d, and f  => a, b, c, d, e, and f Corrected. Thank you.

                (Note: Rearrange your figures)

Line 153: don’t => do not   (Note: a formal writing) Corrected. Thank you.

Table 1: Physical quantities should be italic. Corrected. Thank you.

              (ml => mL)

Figure 2: Please input a "scale bar" so that people can understand your sample’s size  A “scale bar” was added to the figure.

             (Note, at least, in one place, you should input a scale bar.)

Line 176 : attributed to => is attributed to Corrected. Thank you.

Line 190: Physical parameter should be italic. Corrected. Thank you.

Table: Dimension for CE is cm²C^-1 but you wrote cm^-2C^-1 (it is wrong) Corrected. Thank you.

           (Check all the other parts in your manuscript)

Line 205, 207, and 208: CE’s dimension wrong Corrected. Thank you.

Figure 4: y-axis: CE’s dimension wrong Corrected. Thank you.

Line 236: cm²/C => cm²C^-1 (Note: for consistency) Corrected. Thank you.

Line 240: physical parameter should be italic Corrected. Thank you.

Figure 6: Authors showed only 3 SEM figures.  "It is critical." You should include more SEM data according to Table 2’s condition. In the revised manuscript Figure 6 was replaced with one containing SEM images of all films under discussion.

Figure 6: Figure’s caption should be revised. In the revised manuscript Figure 6 was replaced with one containing SEM images of all films under discussion and caption changed accordingly.

                (a), (b), and (c) is not clear. (You wrote a, b and c in the middle)

               WO3=> WO₃  (Note: 3 should be a subscript) Corrected. Thank you.

field emission scanning electron microscope (FE-SEM) => FE-SEM Corrected. Thank you.

    (Note: if you introduce it in the experimental part, only initial is enough)

Figure 6’s caption: the nanostructured film ??? In the revised manuscript Figure 6 was replaced with one containing SEM images of all films under discussion and caption changed accordingly.

(Note: your scale is just 40 um. In this condition, you cannot say anything about "nanostructure". I think it may be a "microstructure")

Figure 7: y-axis’s tile should be in the middle. Corrected. Thank you.

             (Note: now it is at the right corner)

Figure 7’s caption: WO3 => WO₃ (Note: 3 should be a subscript) Corrected. Thank you.

Line 287: WO3 => WO₃ (Note: 3 should be a subscript) Corrected. Thank you.

Line 299: WO3 => WO₃ (Note: 3 should be a subscript) Corrected. Thank you.

Line 307: Conclusion Part Corrected. Thank you.

(You did not show any nanostructure. Hence, you cannot say WO₃ nanostructured thin films)

Otherwise, you should show some nanoscale data, which is missing in this manuscript. 

Line 317: tetragonal crystal ???? Corrected. Thank you.

                (Note: in Line 282, you said it is monoclinic. How it is “tetragonal” suddenly in the conclusion????)

Overall, this manuscript is not much polished.

A major revision is required.

We hope that the revised version of the manuscript is improved and acceptable for publication.

Round 2

Reviewer 3 Report

The manuscript looks find. However, for reader-friendly, during your Proof-Reading, please add (a), (b), (c), (d), (e), and (f) in the SEM figures at the top-left corner, for each of them. Also check English again.  I recommend this paper should be published as it is.