Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript by Bitmets et al reports the enhanced stability in long-term thermoelectric performance of Sb2Te3/PEO hybrids by surface treatment approach. Overall this is a good study with focus on the surface treatment benefits for thermoelectric applications. I have the following comments and suggestions.

1. Suggest to add schematics for the hybrid structure showing how the NPs disperse with the polymer matrix.
2. Suggest to simply main surface bonding change by adding chemical reaction equations or schematics. 
3. How does the oxidation get suppressed by the HDT treatment?
4. The electrical conductivity and Seebeck coefficient trend looks strange with Sb2Te3 percentage in the hybrid (Fig. 5a). Please provide an analysis on why Seebeck is constant while electrical conductivity increases.
5. Electrical conductivity symbol (sigma or s) is not consistent in figures, figure captions and main text.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Editor

 

Here you can find my review of the manuscript titled "Enhanced Stability of Water-Processed Sb₂Te₃:PEO Thermoelectric Hybrids via Thiol-Based Surface Functionalization"

In my opinion, this is a generally good work, addressing a topic of timely relevance. The introduction provides a good overview of the current state of the art, the main problems, and possible solutions. It's perhaps a bit too long, and I suggest shortening it somewhat. Furthermore, the authors should better highlight and clarify the novel elements of their work and its purpose.

Aside from that, I think there are some points that require some revision from the authors before this manuscript is ready for publication.

On lines 73 and following, I generally agree with the authors' statement, but are there any studies on the effects of nanoparticle morphology and shape on these properties? Furthermore, what is the effect of their average size and the width of the particle distribution curve? The authors should add references to this section.

On lines 95 and following, the authors describe the oxidation effects of oxygen and water. I suggest adding more references on this topic. Is there any other evidence regarding the formation of Sb2Te2O5? Could the authors briefly discuss the mechanism of action of water. What are the effects of experimental conditions (pH, temperature, ionic strength, etc.)? Lines 109–111 are in bold. Please correct.

Line 136: What detergent? What were the plasma cleaning conditions? Lines 140 and following: This section is very interesting, but I wonder: how were the nanoparticles handled? Are the authors sure they didn't lose the smallest fraction? Furthermore, would it be useful to characterize these particles? What is their average size, for example? Are there any aggregates, and if so, should they be described?

Figure 4 raises a few questions. The particles clearly have a hexagonal lamellar structure: what is their thickness-to-width ratio? To be certain of the average thickness, we need to measure lamellae oriented in the correct direction: how many particles were measured? Furthermore, what can the authors say about the lateral dimensions? Are these lamellae very uniform or, on the contrary, very different? Subfigure b has a distribution curve that is quite different from the other two, which, on the contrary, are very similar. Can the authors comment? In any case, it would be helpful to show information such as the mean, median, mode, and full-width-at-half-height (FWHM) for these curves, so that they can be better compared.

I really like the fact that the authors introduce the concept of percolation threshold on line 234. However, it needs to be explained better, including with references, especially to similar systems. When and how do organic (polymeric) and inorganic hybrid materials exhibit variations in physical properties such as conductivity?

Looking at Figure 6, it appears that the exponential decay of s occurs much earlier than 8 weeks. For completeness, the authors should show data from an earlier period of aging, around 5 days.

On lines 274 and following, the authors state that "This peak corresponds to the Sb2O5 (Sb-O bond) and also overlaps with the C-O bond peak from PEO polymer. Another peak at 530 eV represents Sb2O3, due to the partial oxidation of the NPs by oxygen, most likely originating from water," referring to Figure 7. It would be useful to also show the spectrum of the polymer matrix for comparison. Furthermore, if the peak in question (partially?) overlaps with that of the C-O bond, how can the authors attribute it to the Sb-O bond in Sb2O5? They should explain and argue further. Is there independent evidence for the presence of this phase? (XRD? EDX with SEM or TEM analysis?)

The authors attribute the presence of Sb2O5 to the fact that Sb2Te3 has partially dissolved and SbCl5 has formed. The chemical steps of this process should be described in a little more detail. Also, I wonder what the effect of a slightly lower HCl concentration would be. Can the authors comment?

 

I invite the authors to respond to these comments of mine, so that their work can be fully publishable.

 

Best regards.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Editor

I have carefully read the revised version of this manuscript and must say that the authors have done a good job.
I'm satisfied with their responses to my comments and the changes they've made to the manuscript. I believe it's now at a good level.

With my best regards.