First-Principles Calculations to Investigate Structural, Electronic, Optical and Magnetic Properties of Pyrochlore Oxides Eu₂Tm₂O₇ (Tm = Hf, Sn, Zr) for Energy Applications

Round 1

Reviewer 1 Report

In this study, electronic, optical and magnetic properties of Eu2Tm2O7 (Tm= Hf, Sn, Zr) are investigated using first-principles based DFT calculations. Ground state properties (electronic, optical and magnetic) of Eu2Tm2O7 (Tm= Hf, Sn, Zr) are studied using FP-LAPW method to get an insight of their prospective applications in photovoltaic, spintronic and TE devices. This is a very interesting work and can be considered for publication. The following comments should be addressed;

1． Make sure all abbreviations are written out in full the first time used. This is particularly important in the abstract and in the conclusions, but work through the entire ms carefully from this perspective.

2． This article uses a lot of theories and formulas, and it is suggested to add the corresponding reference sources.

3． The title describes the application of solar cells, however, the article does not include the application of solar energy. It is suggested to modify it.

4． In the last paragraph of the introduction section, more information should be provided on the main content. Suggest deleting the last sentence.

5． To attract much wider readership, more recent work is advised to be cited: ACS Appl. Nano Mater. 2022, 5, 8557−8565; ACS Sustainable Chem. Eng. 2021, 9, 8306−8314.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

This paper presents a comparative study of Eu-based pyrochlore oxides using ab-initio calculations. The results are well organized  and clearly detailed. They provide an interesting data base for their potential applications.

Minor comments:

- TDOS and PDOS have to be explicited 

- line 246, "for spin down" has to be mentioned

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

Zeesham Abbas and his colleagues have conducted an intriguing first-principles calculation of pyrochlore oxides Eu₂Tm₂O₇ (Tm = Hf, Sn, Zr). In this work, the authors presented an in-depth theoretical study of optoelectronic properties and magnetic properties of Eu₂Tm₂O₇ with the aid of the FP-LAPW method and clarified these materials have potential applications in optoelectronic applications. The comprehensive calculated results including band structures, TDOS, and magnetic properties are interesting. For example, Table 1 shows the magnetic moment of O, Hf, Sn and Zr atoms is negative whereas magnetic moment of Eu-atoms is positive showing their antiparallel arrangement.

However, before the publication of this work, a major revision is necessary. This is because, despite the early description (in Introduction), the authors never truly clarify the possibility of Eu₂Tm₂O₇ (Tm = Hf, Sn, Zr) be using in solar cells from the perspective of high quantum efficiency, tunable bandgap, and long charge carrier lifetime.

The most important issue, how about the quantum efficiency and charge carrier lifetime of Eu₂Tm₂O₇. The authors emphasize that these compounds have potential applications in solar cell based on the calculated results in the title and conclusion. However, in their writing, the authors seemingly only offer the refractive index and reflective index to prove it. I think it is not sufficient for the design of a solar cell. My suggestion is that the authors should do the supplement calculations including effective mass values, carrier mobility, and carrier lifetime. By performing these calculations, the manuscript has the potential to make a valuable contribution to the field.

On the other hand, the authors can adjust the title and some related conclusions, and reorganize the manuscript from a more appropriate viewpoint.

Comments for author File: Comments.docx

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

The reviewer‘s questions have been answered, and the title is revised to be fitted well with the manuscript （from solar cell to energy application）. The quality of the manuscript has been significantly improved after revison. Thus I agree its publication in this journal.