Investigation on the Cu-Dopant-Induced Modulation Effect on the Optoelectronic Efficiency and the Stability of CsPbBr3 Perovskites
, Fangchao Liu 1, Hao Jiang 1, Jialin Wu 1, Qiuhong Huo 1, Zhongchen Wu 1,2, Wei-Yan Cong 1,* and Ying-Bo Lu 1,*Round 1
Reviewer 1 Report
In the review of research article titled: “Investigation on the Cu dopant induced modulation effect on the optoelectronic efficiency and the stability of CsPbBr3 perovskites” by Ma et al., have focused on the theoretical calculations of the material. CSPbBr3 is a versatile material and already many experimental and theoretical reports are present on the material regarding there multifunctional properties.
1. Works lacks the novelty and its description. What new or innovative have they performed in this study which is not reported before? Or this study has brought some improvements in the previous values?
2. In the last section sentence of the abstract authors report “suitable for the blue light 30
3. There exist several recent research articles which have reported better experimental performances, like (Nanomaterials 2022, 12, 3208).
4. LED applications”, have authors reported any study regarding the optical performance of the materials?
5. Energy states or DoS are not enough to describe the optical performances of the materials.
After a careful review, I suggest this study is not suitable to be published in present form, I advise the authors to perform some more measurements to make it more appealing and attractive for the readers.
English is good, I will suggest a careful revision of the manuscript to correct the little grammar mistakes.
Author Response
Comment 1): Works lacks the novelty and its description. What new or innovative have they performed in this study which is not reported before? Or this study has brought some improvements in the previous values?
Response 1): Through systematic first-principles calculations, we investigated the influence of Cu doping on the geometric structure and electronic properties of the perovskite crystal. These descriptions are added to the revised manuscript, which are highlighted in yellow on page 9.
Comment 2): In the last section sentence of the abstract authors report “suitable for the blue light 30
Comment 3): There exist several recent research articles which have reported better experimental performances, like (Nanomaterials 2022, 12, 3208).
Comment 4): LED applications”, have authors reported any study regarding the optical performance of the materials?
Response 2、3、4): I think the 2、3、4 suggestion seems to be a whole piece of advice. In Nawishta’s study, single-layer and multilayer CH3NH3PbIBr2 thin films were successfully grown, maintaining their perovskite structure, and exhibiting leaky ferroelectric behavior. The multilayered thin film showed sharper absorption peaks in the visible region and demonstrated a power conversion efficiency of 7.87% and fill factor of 72% when used as an absorber layer in a photoelectric cell, suggesting their potential for application in optoelectronic and photovoltaic devices.It is highlighted in yellow.
Comment 5): Energy states or DOS are not enough to describe the optical performances of the materials.
Response 5): Regarding this point, this is because the increase in the forbidden band width makes it more difficult for the electronic transition, and the transition becomes more difficult, which will further lead to a smaller probability of the electronic transition at the same energy, so that photons with higher energy can be screened out, that is to say In the range of visible light, only light with higher energy near the blue-violet side is easier to convert into electrons in perovskite, and when the photoelectric conversion process is reversed, it is easier to emit blue light when making LED light. The blue shift can provide an effective idea for us to find complementary blue-emitting LED materials . we have made relevant supplements on the seventh page of the article and highlighted them in yellow.
Reviewer 2 Report
The article considers the effect of adding a copper dopant to increase the optical properties and stability stability of CsPbX3 perovskites, which have great prospects for use as diode materials. In general, the presented work has great potential for practical application, and the data obtained can later be used as an addition to fundamental research aimed at studying the properties of perovskites. The presented results have a sufficient level of novelty, and the applied approaches and methods are fully justified. However, despite the high level of data presented, the article should be finalized taking into account the comments of the reviewer.
1. First of all, the authors of this article should reflect the reasons for choosing the addition of copper as a dopant to the composition of CsPbX3 perovskites, since a lot has been written about the addition and change in the properties of perovskites in this case.
2. When describing the structural parameters, in particular, the effect of copper on the compression of the orthorhombic metal octahedron CsPbBr3, the authors should pay attention not only to the positive effect of reducing the deformation stresses in the crystal lattice, but also to the opposite effect, since compression leads to the appearance of another type of deformation distortion in the structure.
3. The effect of strengthening the perovskite structure should be explained not only by the defect structure, but also by changes in the dislocation density.
4. The authors should pay more attention to the effect of adding copper on the luminescence of perovskites, since the following is not entirely clear from the presented data. In the case of adding copper, the authors point out the appearance of additional vacancies and defects, which, in turn, should adversely affect the change in the optical properties of perovskites due to changes in the refractive indices.
5. Authors should provide data from X-ray phase analysis or X-ray diffraction analysis in order to confirm changes in structural parameters.
Author Response
Comment 1): First of all, the authors of this article should reflect the reasons for choosing the addition of copper as a dopant to the composition of CsPbX3 perovskites, since a lot has been written about the addition and change in the properties of perovskites in this case.
Response 1): In fact, we are very cautious in selecting the doping elements. We have considered various different influencing factors and ultimately chosen a scheme that we believe may yield the most suitable and effective impact. Furthermore, researchers have made significant advancements in the field of Cu dop-ing in perovskite materials. This is attributed to the similarity in oxidation states be-tween Cu and Pb, with Cu exhibiting a considerably smaller atomic radius than Pb. Additionally, the electronegativity disparity between Cu and Br surpasses that of Pb and Br. As a result, numerous studies have been conducted to explore the effects of Cu doping on the optoelectronic properties of semiconductor materials.
Comment 2): When describing the structural parameters, in particular, the effect of copper on the compression of the orthorhombic metal octahedron CsPbBr3, the authors should pay attention not only to the positive effect of reducing the deformation stresses in the crystal lattice, but also to the opposite effect, since compression leads to the appearance of another type of deformation distortion in the structure.
Response 2): This is indeed an essential part that cannot be overlooked when discussing the scientific significance rigorously. We have provided supplementary explanations regarding the deformation and effects influenced in the opposite direction:In accordance with rigorous academic conventions, it is imperative to consider not only the beneficial impacts arising from doping-induced distortions. Evidently, when the Cu-Br bond length is reduced, it is observable that the bromine atom forming the Cu-Br bond experiences elongation due to its proximity to the surrounding lead bro-mide octahedra. However, the degree of deformation along this axis is not particularly substantial. Moreover, since it exclusively affects the nearest adjacent metal octahedra, its influence on the formation energy of bromine vacancy defects is comparatively negligible.
Comment 3): The effect of strengthening the perovskite structure should be explained not only by the defect structure, but also by changes in the dislocation density.
Response 3): From the perspective of dislocation structure, it is indeed possible to perform a theoretical analysis as well . From an alternative standpoint, the reduction in diameter of the dopant ions leads to the alleviation of lattice stress caused by distortion and compression between adjacent lattices. As a result, this release of lattice stress reduces the dislocation density within the crystal, ultimately promoting greater stability of the perovskite structure.
Comment 4): The authors should pay more attention to the effect of adding copper on the luminescence of perovskites, since the following is not entirely clear from the presented data. In the case of adding copper, the authors point out the appearance of additional vacancies and defects, which, in turn, should adversely affect the change in the optical properties of perovskites due to changes in the refractive indices.
Response 4): We have conducted calculations, discussions, and analyses on the influence of optical properties represented by refractive index on the optical characteristics.Cu doping increases the refractive index of the perovskite material, enhancing its interaction with light. This leads to reduced propagation velocity and increased opacity, impacting transparency and light utilization. The higher refractive index also increases astigmatism scattering, reducing optical uniformity and complicating light propagation. These changes affect the material's optical properties, potentially decreasing optoelectronic conversion efficiency. However, the refractive index change is relatively small. Cu doping effectively reduces defects, indicating its importance for improving photoelectric performance.
Comment 5): Authors should provide data from X-ray phase analysis or X-ray diffraction analysis in order to confirm changes in structural parameters.
Response 5): As reviewer suggested, XRD of CsPbBr3 before and after Cu doping are analyzed, which is highlighted in yellow on page 4.
Round 2
Reviewer 1 Report
Authors have revised the manuscript very well. I would like to see this article publish in present condition.
English is fine, just go through once again for minor adjustments.
Reviewer 2 Report
The authors answered all the questions, the article can be accepted.
