Review Reports

Round 1

Reviewer 1 Report

The authors describe how they successfully growth single crystals of ADP (pure and l-lysine added),  obtained in a temperature controlled atmosphere using S-R method. 

 

Some pictures of the final grown crystals should be shown, since that is the main result of this investigation.

 

Unfortunately the characterisation methods, particularly, XRD, Single Crystal and Powder data, are poorly analysed and therefore is very difficult what type of crystal properties can be deduced from the experimental results.

(for instance, what are the intermolecular packing and interaction changes when the doping is present? That may be deduced from the single crystal diffraction data. The same can be said from the powder data patterns)

 

Al the discussion of the thermal behaviour is rather general and difficult to extract any firm conclusion.

 

The same can be said from the IR and Vis-UV spectra.

 

The EDAX characterization seems to detect the presence of C in the doped crystals.

 

The Second harmonic generation (SHG) results need a deeper discussion.

 

There are also several typos along the manuscript.

 

All together, my humbly advice is to make a full and deep revisión of the manuscript, both in formal and scientific grounds, to reconsider for publication.

 

 

Author Response

Comment 1: Some pictures of the final grown crystals should be shown, since that is the main result of this investigation.

Response 1: Authors are heartily thankful of the reviewer for recognizing our work and valuable suggestions to improve the quality of our research paper.

The Picture of grown crystal as well as growth setup is illustrated in figure 2.

Figure 2: Setup for crystal growth by SR method and the grown crystal

Location of Change Section: 3. Experimental procedure: 3.1. Crystal growth

Page No.9; Figure 2. (Highlighted by yellow color)

The corresponding change in revised manuscript: Yes

Comment 2: Unfortunately, the characterization methods, particularly, XRD, Single Crystal and Powder data, are poorly analyzed and therefore is very difficult what type of crystal properties can be deduced from the experimental results.

Response 2: The powder XRD and Single Crystal XRD characterizations are carried out to confirm the structure of grown crystals and impact of L-lysine molecule on structural variations of ADP crystal.

It is reported that the incorporation of doping molecule does not alters the tetragonal symmetry of ADP only slight reduction in lattice parameters and hence volume is noted. This happens when the rate of impurity molecule adsorption is fast compared to the rate of accumulation of the growth entities, it is also confirmed with increased rate of growth in dopped ADP crystals compared to pure crystal. 

Location of Change Section: 4. Result and Discussions: 4.1. Single Crystal X-Ray Diffraction analysis

Page No. 8; (Highlighted by yellow color)

The corresponding change in revised manuscript: Yes (Slight addition) 

Comment 3: The discussion of the thermal behaviour is rather general and difficult to extract any firm conclusion.

Response 3: We have performed thermal analysis to estimate thermal stability and decomposition temperature of the harvested crystals. It is found that on addition of L-lysine the thermal stability of grown crystals reduces by some degrees; for pure ADP it is 214 ºC, whereas for 201 ºC to 204 ºC for 1 and 0.5% of doping concentrations respectively. It is also noted that with increase in doping concentration thermal stability decreases. It may be due to decrease in bond strength and inclusion of defects in crystal on addition of l-lysine in ADP lattice.

Location of Change Section: 4. Result and Discussions: 4.5. Thermal Analysis

Page No. 11 & 13; (Highlighted by yellow color)

The corresponding change in revised manuscript: Yes (Slight addition)

Comment 4: Al the discussion of the IR and Vis-UV spectra is rather general and difficult to extract any firm conclusion.

Response 4: Added more detail discussion on IR and Vis-UV transmission spectra with finding of direct and indirect band gap energy. Also, Tauc’s plot for direct [figure 9 (a)] and indirect [figure 9 (b)] band gap is plotted.

Location of Change Section: 4. Result and Discussions: 4.6. UV-Vis-NIR analysis

Page No. 13, 14 & 15; (Highlighted by yellow color)

The corresponding change in revised manuscript: Yes

 

Comment 5: The EDAX characterization seems to detect the presence of C in the doped crystals.

Response 5: Yes, EDAX characterization is carried out to investigate about the crystal's precursor molecules. For doped crystals, the presence of C atom and its weight percentage confirms the incorporation of organic L-lysine in crystal matrix of ADP.

The corresponding change in revised manuscript: No

Comment 6: The Second harmonic generation (SHG) results need a deeper discussion.

Response 6: The depth of discussion on SHG is increased as per the suggestion. The role of different parameters contributing for enhanced SHG efficiency is explained. The detail process involved in Kurtz-Perry technique is elaborated for clear understanding.

Location of Change Section: 4. Result and Discussions: 4.8. SHG Analysis

Page No. 16 & 17; (Highlighted by yellow color)

The corresponding change in revised manuscript: Yes

Comment 7: The Second harmonic generation (SHG) results need a deeper discussion.

Response 7: There are also several typos along the manuscript.

Location of Change Section:

1. Introduction: Page No. 04; (Highlighted by yellow color)
2. Ammonium dihydrogen phosphate as an optical crystal: Page No. 05; (Highlighted by yellow color)

4.7. Vickers’s Microhardness Analysis: Page No. 16; (Highlighted by yellow color)

5. Conclusion: Page No. 17; (Highlighted by yellow color)

The corresponding change in revised manuscript: Yes

Reviewer 2 Report

The manuscript is interesting and well-written.

I have some comments:

 

1) The figures can be improved. For example, the plots in Figure 3 seem to be horizontally shrinked.

 

2) The font of the inset of figure 7 is very small.

 

3) The bibliography can be extended since the literature related to the field is vast.

 

4) Figure 7: The transmission close to 200 nm seems to show a systematic error. Does it make to show transmission in the UV above 6 eV?

Also around 800 nm there is a systematic error (change of detector?)

 

Author Response

Comment 1: The figures can be improved. For example, the plots in Figure 3 seem to be horizontally shrinked.

Response 1: Authors are heartily thankful of the reviewer for recognizing our work and valuable suggestions to improve the quality of our research paper.

Figure no. 8 is improved as per the suggestion. Figure 3 (now it is numbered as figure 4) the horizontal shrink is intentionally done as in the range 2300 cm^-1 to 3200 cm^-1, no peaks are observed for all the sample, so for better visibility that plane portion is hided.

The corresponding change in revised manuscript: No

Comment 2: The font of the inset of figure 7 (now it is numbered as figure 8) is very small.

Response 2: The all the font in above mentioned figure 7 (due to inclusion of one figure it is numbered as figure 8) corrected to visible size.

Location of Change Section: 4. Result and Discussions: 4.6. UV-Vis-NIR analysis

Page No. 14; (Highlighted by yellow color)

The corresponding change in revised manuscript: Yes

Comment 3: The bibliography can be extended since the literature related to the field is vast.

Response 3: As per the suggestion bibliography is extended from 52 references to 63 references.

Location of Change Section: References

Page No. 14; (Highlighted by yellow color)

The corresponding change in revised manuscript: Yes

Comment 4: The bibliography can be extended since the literature related to the field is vast.

Response 4: As per the suggestion bibliography is extended from 52 references to 63 references [Added references – 44, 45, 48, 49, 50, 51, 54, 57, 58, 59 & 61 ].

Location of Change Section: References

Page No. 19 & 20; (Highlighted by yellow color)

The corresponding change in revised manuscript: Yes

Comment 5: Figure 7 (now it is numbered as figure 8): The transmission close to 200 nm seems to show a systematic error. Does it make to show transmission in the UV above 6 eV? Also around 800 nm there is a systematic error (change of detector?)

Response 5: Probably it is not the reason, Figure 7 (now it is numbered as figure 8) shows the  variation in transmission percentage with wavelength for all the grown crystals. Above 800 nm, i.e. IR region the absorption of radiation by crystal increases and hence the slight depth in curve at this wavelength is observed.    

The corresponding change in revised manuscript: No

Reviewer 3 Report

This manuscript dealt with the fabrication, electronic and optical characterizations of doped ADP specifically for second harmonic generation. 

It seems from the introduction in the beginning, the vision is very broad and the goals are ambitious. However, the experimental outcomes were not exciting. The optoelectronics applications are the main shoot if seen from the title. Instead of focusing on the electro-optical characterizations, the authors listed various chemical characterizations. After all in section 4.8, the SHG power was given with lots ambiguities. For example: to compare the SHG efficiencies, it is important to ensure the volume of the crystal, the excitation power of the pump light are on the same control level. An optical setup to measure this should be clearly shown. 

I think the optical part of this manuscript is a failure (at least in the manuscript presentation). Therefore. I am not able to recommend the publication at current status. 

 

Author Response

Comment 1: This manuscript dealt with the fabrication, electronic and optical characterizations of doped ADP specifically for second harmonic generation. It seems from the introduction in the beginning, the vision is very broad and the goals are ambitious. However, the experimental outcomes were not exciting. The optoelectronics applications are the main shoot if seen from the title. Instead of focusing on the electro-optical characterizations, the authors listed various chemical characterizations. After all in section 4.8, the SHG power was given with lots ambiguities. For example: to compare the SHG efficiencies, it is important to ensure the volume of the crystal, the excitation power of the pump light are on the same control level. An optical setup to measure this should be clearly shown. 

Response 1: Authors are heartily thankful of the reviewer for recognizing our work and valuable suggestions to improve the quality of our research paper.

As per the valued suggestions, the detail discussion is now added for linear and nonlinear optical behaviour of grown crystals and the attempt is made to put detail explanations for parameters responsible for enhanced SHG efficiency. The optical set-up needed to examine SHG efficiency and technique used (Kurtz and Perry technique) is elaborated in depth. While talking about the volume of the crystal, particle size of crushed power, and pumping radiation is mentioned, we have tried to keep all parameters constant for every sample test and ease of comparison.

The present study is expanded to other characterisations (structural, thermal and mechanical properties) as well to investigate the other important parameters for device fabrication. Keeping main focus to optical parameter, the detail study is subjected for only linear and non-linear optical behaviour of grown crystals.

Location of Change Section: 4. Result and Discussions: 4.6. UV-Vis-NIR analysis & 4.8. SHG Analysis

Page No. 13, 14, 15, 16 & 17; (Highlighted by yellow color)

The corresponding change in revised manuscript: Yes

Round 2

Reviewer 1 Report

The manuscript has been improved and the concerns were addressed.

Still, the text needs a final revision to eliminate some typos.

Further, one convincing explanation must be given for the apparent contradiction of the XRD results 'In ADP crystal, addition of l-lysine causes decrease in lattice parameters' and volume and the DTA results 'Hence, DTA curve reveals that thermal stability of the l-lysine:ADP crystals is slightly hindered in comparison to pure ADP crystal'

How can intermolecular packing interactions explain both effects?

Once these final corrections and questions are solved, the manuscript may be accepted. 

Author Response

Reviewer 1:

Comment 1: The manuscript has been improved and the concerns were addressed. Still, the text needs a final revision to eliminate some typos.

Response 1: Authors are heartily thankful to the reviewer for recognizing our work and for valuable suggestions to improve the quality of our research paper.

The complete write-up is checked with the premium version of Grammarly software. Some of the typos have been identified and corrected. ADP: Lysine, 1.5-fold; (NH₃⁺).

Location of Change Section: Abstract; and 2. Ammonium dihydrogen phosphate as an optical crystal

Page No.1 and 5; (Highlighted by green color)

The corresponding change in the revised manuscript: Yes

Comment 2: Further, one convincing explanation must be given for the apparent contradiction of the XRD results 'In ADP crystal, addition of l-lysine causes a decrease in lattice parameters' and volume and the DTA results 'Hence, DTA curve reveals that thermal stability of the l-lysine: ADP crystals is slightly hindered in comparison to pure ADP crystal’.

How can intermolecular packing interactions explain both effects?

Response 2: The incorporation of L-lysine molecule in ADP crystal matrix may leads to an increase in bond order, which is inversely proportional to the bond length. Also, the enhanced growth rate of doped crystals due to the fast absorption rate of impurity molecule may incorporate defects with in. The inclusion of defects and decreased in bond length leads to decrease in thermal stability.

Location of Change Section: 4. Result and Discussions: 4.5. Thermal Analysis

Page No. 13; (Highlighted by green color)

The corresponding change in the revised manuscript: Yes

Reviewer 2 Report

The authors have worked a lot to improve the manuscript.

I am glad that the manuscript has been improved.

I have increased the evaluation of the quality of presentation.

I suggest to accept the manuscript for publication.

Author Response

Reviewer 2

Comment 1: The authors have worked a lot to improve the manuscript. I am glad that the manuscript has been improved. I have increased the evaluation of the quality of the presentation. I suggest accepting the manuscript for publication.

Response 1: Authors are heartily thankful to the reviewer for recognizing our work and considering the paper in its current format.

Reviewer 3 Report

(1) Why is there Sustainability 2022, 14, x FOR PEER REVIEW in the manuscript? The journal is Electrochem. 

(2) In section "4.8 . SHG Analysis", the author Should be responsible for the sincerity of the testing results. The authors used a lot of ambiguous words in this section. for example,

"The whole setup and all the related parameters were set to alike setting for all samples, to attain relative comparison of SHG efficiency."  

"Second harmonic generation (SHG) is nothing but the nonlinear optical phenomenon, where interaction of photon with non-linear material facilitates same frequency photon to effectually combined and produce a photon with twofold the frequency and half the wavelength of the original photons"

It is recommended the authors use more professional description to improve the interest to the readers.

 

Author Response

Reviewer 3:

Comment 1: Why is there Sustainability 2022, 14, x FOR PEER REVIEW in the manuscript? The journal is Electrochem. 

Response 1: Authors are heartily thankful to the reviewer for recognizing our work and for valuable suggestions to improve the quality of our research paper.

Thank you for pointing it out “Sustainability 2022, 14, x FOR PEER REVIEW” in the header of the manuscript. But we have submitted our paper in Electrochem journal format, which we have downloaded from the journal website. We have deleted it. 

Location of Change: Header of each page.

The corresponding change in revised manuscript: Yes

Comment 2: In section "4.8. SHG Analysis", the author Should be responsible for the sincerity of the testing results. The authors used a lot of ambiguous words in this section. for example,

"The whole setup and all the related parameters were set to alike setting for all samples, to attain relative comparison of SHG efficiency."  

"Second harmonic generation (SHG) is nothing but the nonlinear optical phenomenon, where interaction of photon with non-linear material facilitates same frequency photon to effectually combined and produce a photon with twofold the frequency and half the wavelength of the original photons"

It is recommended the authors use more professional description to improve the interest to the readers.

Response 2: The whole setup for SHG Analysis was explain in detail in section “3.3. Characterization”. So, in order to avoid repetation it is not mention in detail again in "4.8. SHG Analysis".

It is mentioned as,

“The Kurtz and Perry powder method was implemented to investigate the grown crystals' second harmonic generation [34]. A Q-switched Nd: YAG laser operating at a wavelength of 1064 nm, with incoming pulse energy of 1.9 mJ/pulse, pulse width of 8 ns, and repetitive rate of 10 Hz, was used to perform the SHG analysis on the salts of pure and l-lysine added ADP.”

The statement,

 "Second harmonic generation (SHG) is nothing but the nonlinear optical phenomenon, where interaction of photon with non-linear material facilitates same frequency photon to effectually combined and produce a photon with twofold the frequency and half the wavelength of the original photons."

This statement is mentioned with the intension to define about the SHG property only, rest of specific detail discussion is provided further about effect of L-lysine molecule doping on SHG efficiency of ADP crystal.

The corresponding change in revised manuscript: No