Formation of LiNbO3 Nanocrystals Using the Solvothermal Method
Round 1
Reviewer 1 Report
The work describes the preparation of lithium niobate nanocrystals (LN NC) using a solvothermal process. Here, the authors' stated goal is to develop a simple and cost-effective process for the production of high-purity nanocrystals with high yield. SEM, EDS and XRD methods are available to study the samples.
The obtained results on the formation of LN NC are quite interesting, however, the motivation for this work is not sufficiently clear. Also, the novelty and usefulness of the work for the scientific community seems limited. Several works on the preparation of LN NC via a solvothermal route are already described in the literature (see e.g. publications from R.F. Ali), including at temperatures in the range of 220 °C . It is not convincingly presented in this manuscript which advantages the described method has over already existing ones, especially in the applicability of the used method (e.g. in medicine or diagnostics), as well as in the quality of the produced NC, e.g. their purity and/or avoidance of agglomerates. Overall, I therefore recommend a fundamental revision of the work with a then new possible submission to Crystals.
More detailed comments are:
The general introduction to the subject of the present work is of limited conviction. The references listed (e.g. 2,3,4) are more related to niche applications of LN NC. This part should be significantly improved.
With respect to common applications of NCs e.g. in medicine or diagnostics, agglomeration of NCs during fabrication should be avoided if possible; however, the work does not address this aspect. Also, the later results just show a strong agglomeration, which clearly limits the practical use of the fabricated NCs. The authors should comment on this fact.
EDS is mentioned as a used investigation method, but the work does not show concrete results obtained with the help of EDS measurements. The previously defined goal of a high purity of the NC or its verification is therefore not pursued further in the work. It also remains unclear why the detection of Zr by means of EDS should be relevant here.
The preliminary investigations show a dominating influence of the morphology of the used Nb2O5 material on the produced NC (see e.g. Fig. 1). Unfortunately, however, the influence of the particle size of the ball-milled Nb2O5 powder, for example, on the NC size is then not investigated further.
In equation (2) an efficiency eta is defined, where here at first the ratio m_1,2 seems to be reversed, so that values >100% seem possible to the equation. Unfortunately, it remains unclear in the following what this quantity is to be used for.
It seems to make sense to define a parameter r for the Li/Nb ratio and to indicate this parameter later in the obtained measurements in order to improve the readability.
Figure 3 shows zero readings for NC particle sizes of 60nm and 100nm in all cases. It is therefore unclear why it is claimed that particles sizes "are in the range of 60-100nm".
In the caption of Figure 4 the obtained data is discussed again, thus just repeating what is already written in the text section.
The whole manuscript should be spelled checked in order to correct several errors (e.g. relevated -> revealed, secons-> second, stated-> started etc.).
All figures contain top headings with a description of the content, which should be deleted.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Manuscript No: crystals-2113273
Title: Formation of LiNbO3 nanocrystals by solvothermal method
Authors: Gabriella Dravecz , Tamás Kolonits and László Péter
A. Overview
1. In this manuscript the authors report experimental work on optimization of parameters of solvothermal synthesis of lithium niobate nanocrystals and its characterization.
2. The contents are expressed clearly; the manuscript is well organized and it is written in reasonable English.
Although, a careful reading of the text is needed - several typos and grammar issues.
3. The authors have acknowledged recent related research.
4. As long as my knowledge, the work presented is original.
B. Detailed analysis.
Abstract: Try to re-organize the ideas in each paragraph. State briefly what you did, how did you do it, the quantitative results you and the novelty of your work.
1. Introduction: provides an interesting approach to the subject and there are up to date references. Perhaps a bit too short – authors could provide a deeper insight in the field.
2. Materials and Methods : an accurate and detailed description of the material and methods used is presented
Quality of figures and graphs is not good. Keep Graphs in closed squares for the sake of clarity. Use the same layout for all figures and do not repeat information on figure that it is already in the legend.
C. Overall assessment
The work presented here is very interesting and has potential for further development in the field. In my opinion the manuscript can be published after minor corrections.
D. Review Criteria
1. Scope of Journal
Rating: Medium
2. Novelty and Impact
Rating: Medium
3. Technical Content
Rating: Medium
4. Presentation Quality
Rating: Medium
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
