Fabrication and Luminescent Properties of Zn–Cu–In–S/ZnS Quantum Dot Films under UV Excitation

Round 1

Reviewer 1 Report

This manuscript mainly introduce a detailed luminescent analysis of Zn-Cu-In-S/ZnS QDs in PMMA under UV excitation, the results is attractive but not sufficient to support the conclusion.

Here's my personal comments and suggestions on this manuscript

In line 1, the definition of QDs size (2-10nm) is not rigorous, for example, the self-assembled QDs are typically 5-50nm in size.

As shown in figure 3, the authors should also supply a spectral presentation of QDs luminescent under this UV irradiation. Besides, the legend of figure 3 is hard to distinguish each line. Try to use different color or more clear labels. 

In figure 4(a), as last comments, the legend also need to improved.

In figure 4(b) and 6(b), what's the power of incident UV radiation?

In figure 6(a) and 6(b), the backward luminescent intensity of QD150 is obviously different (>250 or <150), please confirm the data.

In line 175 to 177, the statement of "The latter implies that increasing the power of incident UV photons, the amount of internal QD-UV interactions is also increased, thus providing an enhanced light production" is questionable. Because the percentage of transmitted UV is almost constant, the QD-UV interactions should keep stable. The authors need to give a more reasonable explanation.

In figure 9 and 10, there should be scale bar to display the size of QDs aggregations. The devices and parameters of X-ray imaging and SEM imaging need to be described in section "Materials and Methods". The SEM images of QD25, QD100 and QD150 are needed as well 

Generally, the resolution of regular X-ray and SEM imaging is not enough to detect QDs. Try to use TEM to get clear QDs images.

In table 3, what are the definition and unit of column "Area"?

Author Response

Response on Reviewer’s 1 comments:

Reviewer 1

Comments and Suggestions for Authors

 

This manuscript mainly introduce a detailed luminescent analysis of Zn-Cu-In-S/ZnS QDs in PMMA under UV excitation, the results is attractive but not sufficient to support the conclusion.

 

Answer

Thank you for your valuable comments and your effort upon our work. The text was revised, following Reviewer’s comments.

 

Here's my personal comments and suggestions on this manuscript

In line 1, the definition of QDs size (2-10nm) is not rigorous, for example, the self-assembled QDs are typically 5-50nm in size.

 

Answer

Thank you for your comment. The corresponding statement was revised following Reviewer’s comment. Please see changes highlighted with yellow color.

 

As shown in figure 3, the authors should also supply a spectral presentation of QDs luminescent under this UV irradiation. Besides, the legend of figure 3 is hard to distinguish each line. Try to use different color or more clear labels.

 

Answer

Spectral presentation of the forward luminescent light for the QD250 sample was added in Fig.3b, following Reviewer’s comment.  

 

In figure 4(a), as last comments, the legend also need to improved.

 

Answer

Fig.4a was revised, following Reviewer’s comment.

 

In figure 4(b) and 6(b), what's the power of incident UV radiation?

 

Answer

The incident UV radiation power in now provided following Reviewer’s comment.

 

In figure 6(a) and 6(b), the backward luminescent intensity of QD150 is obviously different (>250 or <150), please confirm the data.

 

Answer

Thank you for your comment and accept our apologies, since in the initial submitted manuscript a wrong figure was introduced instead of Fig6b. Thanks to your comment we replaced Fig6b with the correct one.   

 

In line 175 to 177, the statement of "The latter implies that increasing the power of incident UV photons, the amount of internal QD-UV interactions is also increased, thus providing an enhanced light production" is questionable. Because the percentage of transmitted UV is almost constant, the QD-UV interactions should keep stable. The authors need to give a more reasonable explanation.

 

Answer

The corresponding statement was removed in order to avoid confusion to readers.

 

In figure 9 and 10, there should be scale bar to display the size of QDs aggregations. The devices and parameters of X-ray imaging and SEM imaging need to be described in section "Materials and Methods". The SEM images of QD25, QD100 and QD150 are needed as well

 

Answer

Thank you for your comment. A scale bar was added in Fig.9. Following both Reviewers’ comments, regarding SEM results, we decided to remove the corresponding images from the text, since SEM imaging is not enough to detect QDs and unfortunately, we do not have any access to TEM. Additional data for the X-ray irradiation was provided, following Reviewer’s comment. 

 

Generally, the resolution of regular X-ray and SEM imaging is not enough to detect QDs. Try to use TEM to get clear QDs images.

 

Answer

Please see the previous comment.

 

In table 3, what are the definition and unit of column "Area"?

 

Answer

The definition and unit of column "Area" is now provided in the revised manuscript, following Reviewer’s comment.

Reviewer 2 Report

The authors provide a paper dealing with the fabrication and luminescent properties of Zn-Cu-In-S quantum dot (QD) films. The paper can be of interest for applied sciences, however it needs MAJOR revisions:

1.       The morphological characterization of the QD films as reported in Figures 9 and 10 is quite poor. XRD imaging resemble a gray scale and the SEM figure is very poor. I wonder how it has been possible on the basis of these images to determine the size distribution of the QD. Scale bar in the SEM image is also missing. The authors must produce higher quality images while proving a better discussion. I also believe that this characterization must be put at the beginning of the result and discussion section and not at the end.

2.       Following the previous point, I think it can be also useful to add some TEM images of the QD system to have a better understanding of the size distribution and the shape, while providing information about the crystalline structure.

3.       I would like that the authors comment about the role of the QD composition on the luminescent properties. As a matter of facts, as for other materials, including thin oxide films the composition can play a key role. The authors can be helped by the following papers that must be included in the discussion doi.org/10.1016/j.tsf.2011.10.072 and 10.1088/0957-4484/23/36/365706 in which the authors can see that the optical properties of Al doped ZnO thin film are affected by the composition and specifically by the O vacancies.

4.       The authors must clearly comment on the effect of QD size distribution and composition on the luminescent properties.

Author Response

Response on Reviewer’s 2 comments:

Reviewer 2

 

Comments and Suggestions for Authors

 

The authors provide a paper dealing with the fabrication and luminescent properties of Zn-Cu-In-S quantum dot (QD) films. The paper can be of interest for applied sciences, however it needs MAJOR revisions:

 

Answer

Thank you for your valuable comments, your effort upon our work and your recommendation.

 

1.       The morphological characterization of the QD films as reported in Figures 9 and 10 is quite poor. XRD imaging resemble a gray scale and the SEM figure is very poor. I wonder how it has been possible on the basis of these images to determine the size distribution of the QD. Scale bar in the SEM image is also missing. The authors must produce higher quality images while proving a better discussion. I also believe that this characterization must be put at the beginning of the result and discussion section and not at the end.

 

Answer

Thank you for your comment. Since from the SEM images couldn’t obtain size distribution results and following both Reviewers’ comments, we decided to remove SEM data.

 

2.       Following the previous point, I think it can be also useful to add some TEM images of the QD system to have a better understanding of the size distribution and the shape, while providing information about the crystalline structure.

 

Answer

Thank you for your comment but unfortunately, we do not have any access to TEM.

 

3.       I would like that the authors comment about the role of the QD composition on the luminescent properties. As a matter of facts, as for other materials, including thin oxide films the composition can play a key role. The authors can be helped by the following papers that must be included in the discussion doi.org/10.1016/j.tsf.2011.10.072 and 10.1088/0957-4484/23/36/365706 in which the authors can see that the optical properties of Al doped ZnO thin film are affected by the composition and specifically by the O vacancies.

 

Answer

Thank you for your comment. The discussion section was updated following, Reviewer’s comment. Please see changes with green color.

 

4.       The authors must clearly comment on the effect of QD size distribution and composition on the luminescent properties.

 

Answer

Thank you for your comment. The discussion section was updated following, Reviewer’s comment.

Round 2

Reviewer 1 Report

Thanks for the authors with their carefully response and answers for my comments and suggestions, then I feel more comfortable with this revised manuscript. As results, there's only a few problems the authors need to take care.

As the SEM images have been removed, the x-ray imaging is the only morphology characterization of QDs. The quality of X-ray images (Figure 4) should be improved, especially the QD25, it's too dark to see anything.

In figure 5(d), it seems like the data points of QD25 under 7.3W and 8.9W UV are missing. Please confirm these datas.

In figure 6(a), does the data come from the average calculation or under a special intensity of UV. Please indicate it in the statement.

Try to revise the formats of  figures (e.g. fig,5d ) to make sure readers can distinguish the data points easier. 

After all, this manuscirpt could be considered to be accept after the minor revision I mentioned.

Author Response

Response on Reviewer’s 1 comments:

Reviewer 1

 

Comments and Suggestions for Authors

 

Thanks for the authors with their carefully response and answers for my comments and suggestions, then I feel more comfortable with this revised manuscript. As results, there's only a few problems the authors need to take care.

 

Answer

Thank you for your valuable comments and your effort upon our work. The text was revised, following Reviewer’s comments.

 

As the SEM images have been removed, the x-ray imaging is the only morphology characterization of QDs. The quality of X-ray images (Figure 4) should be improved, especially the QD25, it's too dark to see anything.

 

Answer

Thank you for your comment. The quality of the X-ray images was improved following Reviewer’s comment. Please see changes highlighted with yellow color.

 

In figure 5(d), it seems like the data points of QD25 under 7.3W and 8.9W UV are missing. Please confirm these datas.

 

Answer

Thank you for your comment. Figure 5d was updated, following Reviewer’s comment.  

 

In figure 6(a), does the data come from the average calculation or under a special intensity of UV. Please indicate it in the statement.

 

Answer

Thank you for your comment. The text was updated by providing the value of the incident UV radiation power, following Reviewer’s comment.

 

Try to revise the formats of  figures (e.g. fig,5d ) to make sure readers can distinguish the data points easier.

 

Answer

The figures were revised following Reviewer’s comment.

 

After all, this manuscirpt could be considered to be accept after the minor revision I mentioned.

 

Answer

Thank you for your comment and your decision upon our manuscript.   

 

 

Reviewer 2 Report

The authors improved the quality of the paper by answering to my questions and comments. However, the paper has not reach yet the quality to be accepted in Applied Sciences. The main point is related with the fact that the authors removed the SEM images which were of too low quality but they did not provide details about how they measure the size of the plasmonic NPs. I would like that the authors provide clearly how the measure of the size of QD is determined, while focusing on the relationship between the size of QDs and the optical properties.

Author Response

Response on Reviewer’s 2 comments:

Reviewer 2

 

Comments and Suggestions for Authors

 

The authors improved the quality of the paper by answering to my questions and comments. However, the paper has not reach yet the quality to be accepted in Applied Sciences. The main point is related with the fact that the authors removed the SEM images which were of too low quality but they did not provide details about how they measure the size of the plasmonic NPs. I would like that the authors provide clearly how the measure of the size of QD is determined, while focusing on the relationship between the size of QDs and the optical properties.

 

Answer

Thank you for your valuable comments, your effort upon our work and your recommendation. The size of the ZnCuInS/ZnS QDs was obtained from PlasmaChem GmbH datasheet.

https://www.plasmachem.com/download/PlasmaChem-General_Catalogue_Nanomaterials.pdf  

Please see the highlighted text with green color.

 

Round 3

Reviewer 2 Report

-

Author Response

Response on Reviewer’s 2 comments:

Reviewer 2

 

Comments and Suggestions for Authors

 

-

 

Answer

Thank you for your valuable comments, your effort upon our work and your decision. Various corrections regarding the English language and style were performed.

Author Response File: Author Response.pdf