Peer review of: Hybrid plasmonic nano-emitters with controlled single quantum emitter positioning on the local (2020)

Reviewers' comments: 
Reviewer #1 (Remarks to the Author): 

The manuscript reports the fabrication of hybrid nanoemitters made of quantum dots distributed 
over metallic nanoparticles. The originality of the paper is to manage to control the position of the 
emitters in certain areas around the metallic nanoparticles. This is achieved by embedding the 
emitters in a polymer which is then illuminated by the local field around the particle. After 
development, the QDs remains only where the local field was larger than a polymerization 
threshold. As a result, the hybrid nanoparticle has non-isotropic absorption and emission 
properties. 

This is an interesting paper that I recommend for publication after revision. I have a number of 
remarks and questions. 

1. The main concern is to improve readability of the manuscript. 
a. It contains at least 15 acronyms (HPN, MNP, NE, LDOS, PL, GNC, ITO, CTAB, SEM, AFM, FDTD, 
PETA, 2PP, QD, TEM). I acknowledge that some of them are well known and that molecules need 
to be named. Nonetheless, 2PP, HPN, MNP, NE, GNC are not very helpful. It makes the reading 
difficult so that the number should be reduced. 
The manuscript reports the fabrication of hybrid nanoemitters made of quantum dots distributed 
over metallic nanoparticles. The originality of the paper is to manage to control the position of the 
emitters in certain areas around the metallic nanoparticles. This is achieved by embedding the 
emitters in a polymer which is then illuminated by the local field around the particle. After 
development, the QDs remains only where the local field was larger than a polymerization 
threshold. As a result, the hybrid nanoparticle has non-isotropic absorption and emission 
properties. 

This is an interesting paper that I recommend for publication after revision. I have a number of 
remarks and questions. 

1. The main concern is to improve readability of the manuscript. 
a. It contains at least 15 acronyms (HPN, MNP, NE, LDOS, PL, GNC, ITO, CTAB, SEM, AFM, FDTD, 
PETA, 2PP, QD, TEM). I acknowledge that some of them are well known and that molecules need 
to be named. Nonetheless, 2PP, HPN, MNP, NE, GNC makes the reading difficult so that the 
number should be reduced. 
b. I recommend to shorten the paper. Many details should be moved to methods or 
supplementary. 
c. There are sentences that should be corrected: 
The resulting polarization dependence of the photoluminescence has been analyzed and quantified 
on the bases new specific parameters whose use and definition 

Compared to the nanocube case, the dipolar near field distribution yields of 2PP process with 
reduced control over. 

2. The discussion of the parameter eta (eq. (4) ) is not convincing and should be better explained 
and demonstrated or removed. On one hand, Fig. (7) does not compare on the same graph this 
quantity with the data which are in Fig 3-4. There is only a trend agreement. On the other hand, 
the introduction of this quantity is not motivated. If it is expected that it varies like the signal, it 
should be derived starting from Eq. (1). 
The same remark appplies to delta’. It should be specified that max and min are defined when eta 
varies as a function of angle (presumably). It is unclear if the agreement between delta and delta’ 
is accidental or whether it is expected on the basis of some physical arguments. Without a physical 
argument predicting this behaviour, in my opinion, there are not enough evidences to draw any 
useful conclusion at this stage. 


Reviewer #2 (Remarks to the Author): 

The manuscript presents the preparation and characterization of hybrid light emitters based on 
plasmonic particles and quantum dots. The fabrication method is based on plasmon-enhanced two-
photon polymerization and enables the authors to position the quantum dots at different positions 
around the metal particles. For optical characterization, two quantities are defined: the spatial 
overlap integral between emitters and the plasmonic field, and an excitation polarization contrast. 

Positioning emitters near plasmonic particles is not novel, as the authors also acknowledge in the 
introduction. Several methods were developed over the years: chemical linking, AFM-based 
positioning, lithography methods, or DNA assembly (not cited by the authors). Part of the authors 
developed over the last decade methods based on photopolymerization. Compared to previous 
demonstrations based on photopolymerization, I am afraid that the work could be considered 
incremental. The possible novelty then focuses mostly on analyzing the spatial overlap integral for 
single nanoparticles, but still it does not provide new knowledge gain. There are no significant 
technical issues, but I believe that the article will not be influential enough in the (sub-)field to 
warrant publication in Nature Communications. 

The manuscript might benefit from attention to the following points: 
- Equation 1 seems to neglect Stokes shift (wavelength dependence of excitation and emission). 
- Please substantiate the claim that “the HPNs are stable over time. In particular, they do not 
suffer from photobleaching” with data. How long were the HPNs exposed to light to reach this 
conclusion? How? Please quantify it. 
- Can the authors at least estimate the number of quantum dots attached to each nanocube? 
- Figure 4b: please describe better the meaning of this image composition, with more accuracy, as 
it is open to interpretation. Is it precisely the same GNC that is covered with polymer in Figure 4a? 
It is strange to merge two SEM images instead of highlighting the profile of the GNC on the final 
nanostructure. 

Ps: There is an incomplete sentence: “Compared to the nanocube case, the dipolar near field 
distribution yields of 2PP process with reduced control over”.