Bi-Function TiO₂:Yb³⁺/Tm³⁺/Mn²⁺-Assisted Double-Layered Photoanodes for Improving Efficiency of Dye-Sensitized Solar Cells

Round 1

Reviewer 1 Report

This is an interesting article that can be recommended for publication, but after clarifying and detailing some parts of the text.

 

1. Line 58. Introduction. Up to this point, Titanium Oxide's motivation has not been revealed. All previous references were chosen in a chaotic manner and it is not clear on what basis they were selected
2. Furthermore, absolutely necessary to reflect what has been done in recent years on TiO2 and its luminescence properties .Consider, for example, some of the recent MDPI papers: Tsebriienko, T.; Popov, A.I. Effect of poly(titanium oxide) on the viscoelastic and thermophysical properties of interpenetrating polymer networks. Crystals2021, 11, 794. 

Jarosz-Duda, A.; O’Callaghan, P.; Kuncewicz, J.; Łabuz, P.; Macyk, W. Enhanced UV Light Emission by Core-Shell Upconverting Particles Powering up TiO₂ Photocatalysis in Near-Infrared Light. Catalysts 2020, 10, 232. https://doi.org/10.3390/catal10020232

3. Unfortunately, the introduction also does not explain why exactly nanospheres and what the optimal concentration of impurities should be?
4. Accuracy in hundredths of a percent is given in the text needs strict justification.
5. A more detailed description is required of how the data in Fig. 4 were obtained and what the measurement error is ?

Author Response

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Reviewer 2 Report

In the present study, the authors developed dye-sensitized solar cells (DSSCs) based on double-layered photoanodes of TiO₂/TiO₂:YTM with the aim of improving the solar spectral response of DSSCs and, consequently, their conversion efficiency. The experimental results demonstrated the enhanced performance of the DSSCs based on TiO₂/TiO₂:YTM in relation to that with TiO₂/TiO₂ double-layered photoanodes.

The work is very interesting and well written. Nevertheless, before publication of this manuscript, I would like the authors to address the following recommendations:

1. Please explain in more detail why DSSCs enable “large-scale fabrication, low cost, environmentally friendly and potential flexibility 30 [1].” compared to other solar cells.
2. I recommend adding a table with the summary of the DSSCs state-of-the-art, namely concerning the cited work. The properties of the photoanodes used, and respective PCEs, must be included.
3. I also suggest adding of a schematic design of the double layered DSSC structure.
4. Higher PCEs of 7.52% [5] and 9.5% [13] have already been achieved using other UC materials, as cited by the authors. Therefore, I would like the authors to clarify why they chose TiO₂/TiO₂:YTM over other materials. What are the main advantages and disadvantages of the UC materials previously studied, in relation to the present one?
5. In line 136, I suppose the authors meant “As seen in Figure 4(a)”.
6. In line 156, why those values are obvious?

Comments for author File: Comments.pdf

Author Response

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Reviewer 3 Report

The manuscript reports the upconversion phenomenon of light to increase the efficiency of TiO₂ based DSSCs. The authors described the use of Yb and Tm as doping agents to improve the light absorption efficiency by forming the double-layer photoanode.  The following minor comments should be considered in the revised version.

1. The explanation regarding the role of Mn²⁺ is missing.
2. The text regarding the EIS data is not convincing and needs better explanation.
3. There are some inconsistencies in the text, please revise carefully.

Author Response

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Reviewer 4 Report

REFEREE REPORT

on paper “Bi-Function TiO2:Yb3+/Tm3+/Mn2+ Assisted Double-Layered Photoanodes for Improving Efficiency of Dye-Sensitized Solar Cells”

by authors Xiang Fu, Xiaolong Li  and Yannan Qian,

submitted to Coatings

 

The paper “Bi-Function TiO2:Yb3+/Tm3+/Mn2+ Assisted Double-Layered Photoanodes for Improving Efficiency of Dye-Sensitized Solar Cells” is devoted to preparation and investigation of the Bi-function TiO2:Yb3+/Tm3+/Mn2+ assisted double-layered photoanode. The proposed double-layered photoanode could efficiently upconvert the near-infrared light into blue and red visible emissions absorbed by N719 organic dye and act as light scattering layer. SEM, XRD, UC PL spectroscopy techniques were applied for the samples characterization. The topic of this paper is critically actual especially Dye-sensitized solar cells. The data are reliable and do not cause much doubt. Nevertheless, there are several points before the paper can be published. I hope that authors after major revisions can improve the paper and can publish it in Coatings.

 

1. Please include the information about fabrication method in Abstract.
2. Authors discussed the microstructure and structure features of the investigated materials but the information about the results didn’t presented in Abstract part. Please write some sentences about main results.
3. The Introduction part must be improved with literature in the field of using TiO2 material and I suggest using the following reference (see and discuss: https://doi.org/10.1016/j.radphyschem.2021.109556).
4. The information about size distribution of the TiO2 before and after doping should be added to the Results and Discussion part, please see and discuss https://doi.org/10.3390/nano10061245.
5. How do you explain the change of the microstructure after TiO2 doping?
6. Please indicate the phases in XRD patterns.
7. Please use the Scherrer formula for the CSR calculation.
8. The Conclusion part is too short, please improve it.
9. There are some insufficient typos and English mistakes in the text.

 

But any way I impressed by this paper. But authors must explain some details and improve the paper in accordance with my comments. The paper should be sent to me for the second analysis after the major revisions.

Author Response

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Round 2

Reviewer 1 Report

After careful revision, the new version of the manuscript can be recommended for publication.

Reviewer 4 Report

It can be accepted