Peer review of: Rapid and high-resolution patterning of microstructure and composition in organic semiconducto (2020)

Reviewers' Comments: 
 
Reviewer #1: 
Remarks to the Author: 
The authors reported organic molecular patterning concept using solution-processed ‘molecular 
gate’ interlayer between target layer and donor layer. The molecular gate serves as a 
semipermeable membrane which prevents uncontrolled diffusion of the functional compound in 
donor layer into the target layer, and only passes the diffusion of functional compound when 
suitable stimulus is applied, which is laser induced heat in this study. The demonstrated data show 
that this concept can change the local properties of target layer, such as crystallization, chain 
orientation, and doping. 
Although this manuscript proposes interesting approaches and results about organic material layer 
patterning using molecular gate concepts, the quality of this manuscript seems not suitable for 
publication in Nature Communications due to the following issues. 
 
1. The most critical issue is about the title and main storyline of manuscript. Authors emphasize 
that this method can combine the spatial resolution of photolithography and versatility of printing 
method. However, this method is fundamentally different from photolithography and printing 
method, therefore, that kind of comparison cannot be made reasonably. For the fabrication of 
various electronic devices, photolithography and printing are usually utilized to pattern target layer 
‘physically’ for the formation of desired shapes or structures, and this is one of the most important 
steps in the fabrication processes. For example, semiconducting layer of each unit channel in FET 
arrays or LED arrays should be physically separated from each other. However, the method 
proposed in this manuscript is just about changing local properties or components of target layer 
using selective diffusion of donor compound which can be considered as chemical patterning rather 
than physical patterning of target layer. For more certain comparison, this method can pattern the 
P3HT layer with selective dopant diffusion to have partially different conductivity area, however, 
P3HT layer itself cannot be patterned, while printing can make it possible. Due to this issue, 
current title and the direction of main storytelling which includes comparison between 
photolithography and printing should be revised to emphasize the novelty of chemical patterning. 
 
2. Due to the above issue, this method cannot have any novelty when considering conventional 
photolithography, printing, and LIFT methods which are usually used for fabrication of electronic 
devices. 

3. In the manuscript, it is written that small functional molecules of donor compounds are diffused 
through molecular gate by photo-induced thermal and solvent-vapor-based stimuli. However, in 
my opinion, it seems quite difficult to control pinpoint diffusion because heat and solvent-vapor 
spread easily and cannot be controlled minutely, which may cause inevitable unintended diffusion 
of small molecules into target layer. Although the authors proposed the power and moving speed 
of laser are the key parameter to control the diffusion, other parameters which may affect small 
molecule diffusion properties or techniques to prevent spread of heat and solvent-vapor should be 
proposed for fine and high-resolution patterning. 
 
4. In addition, the stability issue of the patterned layer should also be addressed. It seems that 
small molecules diffused into the target layer can be diffused to the non-patterned area of target 
layer after patterning process due to the external stimuli, such as heat, or the elapse of time. If 
diffused small molecules can spread into the other area of target layer after patterning, this 
method cannot be utilized. Therefore, I recommend authors add the stability data of the patterned 
layer. 
 
In my opinion, due to the above issues, this manuscript is not suitable for publication in Nature 
Communications. 
 
 

Reviewer #2: 
Remarks to the Author: 
Perevendentsev et al discuss a technique for the patterning of organic semiconductors. They 
propose a sequential solution-based deposition on a target semiconductor layer using an interlayer 
followed by a functional layer. Some points are noted below: 
1. While this appears to be a promising technique, the presentation of the basic concept and its 
application are somewhat difficult to follow. The authors have developed a strategy using 
terminology that is not easy to understand. The schematic shown in Figure 1 should better help in 
demonstrating the technique, perhaps with simple or complex features formed. With a scale bar of 
5 mm, it is unclear how this is a micropatterning approach. Importantly, it would be very helpful if 
the patterning demonstration of this technique could be clearer (other than Figure 4g, the claim of 
high-resolution patterning is not borne out). 
2. The authors discuss the potential issue of delamination of adjacent layers upon physical aging 
or flexure. However, in this work, they have merely speculated on the stability of their technique 
(e.g. “incorporation of donor compounds within the target film”). No experimental data has been 
provided to support their conjecture. Given that this is an important concern for such systems, the 
stability to either flexure or aging or both needs to be demonstrated. 
3. Can this technique be used on substrates other than ITO/glass as demonstrated? For translation 
to “roll-to-roll”, this discussion would be pertinent. 
4. Figure 6 is confusing. How were the “plausible extensions” determined? It is unclear how the 
technique is extensible to metamaterials for instance. 
5. What is the height of the features that can be formed? 
6. There is extensive discussion on the speed of this technique. However, in the absence of context 
or comparison to other methods, the advantage is not clear. By switching to electron beam or 
AFM, this will likely change (p. 23). 
7. There are also several works in the area of patterning various forms of organic electronics, 
including but not limited to conducting polymers. The authors should consider these to establish a 
clear context for this technique (ref 9 from Menard is a good start but is dated – several papers 
since then have advanced the field). This holds for many of the references cited which are from 
the previous decade. Given the sophistication of some of these reports, the advance of this work 
needs to be more clearly demonstrated. 
 
 
 
Reviewer #3: 
Remarks to the Author: 
In their manuscript the authors describe a process driven by laser light or solvent vapor jets to 
achieve local diffusion of functional small‐molecular compounds through a solution‐processed 
‘molecular gate’ interlayer. The authors show how this diffusion process can be used to pattern 
organic semiconductor thin films. The process can also be used for the diffusion of a functional 
donor compound by locally applying heat or solvent vapor to modify the conformation, orientation 
or crystallization of the polymer chains in the target films. Furthermore, local doping of the target 
films is also demonstrated with this process. The process described is novel, original in its 
implementation and clearly of interest to the organic electronic community. 
 
To strengthen their discussion the authors cold consider providing more details on patterning 
speeds vs. minimum feature size and since this technique is a serial patterning process how its 
write speed compares to parallel patterning processes such as photo-lithography. Since the 
process seems to be diffusion driven, then more details on the patterning speed in terms of 
diffusion lengths (and temperature) would be useful as well. Presenting these different parameters 
on a table would help to better understand the capabilities of the process and how it compares to 
other serial patterning or direct-write techniques.