A Study on Optical Properties of Zinc Silicate Glass-Ceramics as a Host for Green Phosphor

Round 1

Reviewer 1 Report

The article titled „A Study on Optical Properties of Zinc Silicate Glass ceramics as a Potential Host for Green Phosphor” deals with an interesting and currently important subject of fabrication of glass-ceramic material from the low-cost precursor WRHA.

Although the article is properly structured and the employed techniques are relevant, it is poorly written. The whole manuscript is in need of general English correction and some paragraphs have to be completely rewritten to have explanatory power for the observed phenomena. Therefore, I recommend the article for publication after a major revision.

My comments are as follows:

1. I do not see any reason to include the word “potential” in the title since the material was demonstrated to exhibit green luminescence
2. In the Introduction, authors should include more citations of the relevant studies using WRHA for the synthesis of luminescent materials, both recent and initial (e.g. F. Adam, S. Balakrishnan and P.-L. Wong, J. Phys. Sci., 2006, 17, 1–13)
3. In the Introduction, the benefits of using the WRHA are repeated in both paragraphs.
4. In Materials and Methods, the authors do not explain why they use even amounts of WRHA and ZnO, when the final product has 0.55/0.45 ratio
5. The authors do not explain the difference between the Archimedes density and the true density, as well as how the true density was obtained for the samples.
6. Table 1 is unnecessarily mentioned three times in the single paragraph.
7. Table 1. has no units for density.
8. Fig. 3 has no labels or description for a) – g)
9. Although in Materials and Methods authors describe the equipment used for absorption spectra measurement, no absorption spectrum is present or described in the manuscript.
10. The paragraph concerning the photoluminescence is very unclear and needs to be thoroughly rewritten. Besides the usage of correct terminology e.g. “radiative”, instead of “radioactive”, I expect the authors to clearly explain the origin of each emission band: green (529 nm), yellow (570 nm) and red (682 nm). From the present version of the paragraph, I understood, that the causes of the luminescence in this material are recombinations of excited electrons and holes in defect states. The authors cite articles (although not the primary sources), that attempt to explain the mechanism but fail to convey it in the paragraph. I suggest to study the primary sources for this matter:

M.S. Ramanachalam, A. Rohatgi, W.B. Carter Sch, J.P. Schaffer, T.K. Gupta, J. Electron. Mater., 24 (4) (1995), pp. 413-419

1. Liu, A.H. Kitai, P. Mascher, J. Lumin., 54 (1992), pp. 35-42
2. Riehl, J. Lumin., 24–25 (1981), pp. 335-341

and summarize the most probable transition or mechanism for each of the emission bands.

Author Response

Dear editorial board and reviewer of JOURNAL of APPLIED SCIENCES,

Please find an attachment regarding the response to the reviewer's comments entitled "Answer to reviewer 1".  

Author Response File: Author Response.docx

Reviewer 2 Report

The authors reported the structural and optical properties of zinc silicate glass-ceramics using the so-called waste materials (WRHA) as the starting materials. Relative density, XRD, SEM, FTIR and PL emission spectra are presented. I recommend it to be published in Applied Sciences after minor revision. Some questions and comments are listed below:

1. It is interesting to see the WRHA can be efficiently used for making glasses and glass ceramic. It is recommended to give more information about the preparation method, especially how to purify the WRHA as the raw materials for the preparation following the stoichiometry
2. Two PL emission bands are observed around 570 nm and 682 nm in glass-ceramics. So what is the excitation wavelength for the measurement, and what is the origin of these two emission peaks. They are belong to the intrinsic defects or from some impurities? Just showing peaks without explanation is not a scientific article.

Author Response

Dear editorial board and reviewer of JOURNAL of APPLIED SCIENCES,

Please find an attachment regarding the response to the reviewer's comments entitled "Answer to reviewer 2".  

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The manuscript titled “A Study on Optical Properties of Zinc Silicate Glass-ceramics as a Host for Green Phosphor” has been improved tremendously in comparison to its previous version. I recommend it for publication in Applied Sciences.